EVALUATION KIT
19-1230; Rev 2a; 6/97
AVAILABLE
1GHz, Low-Pow er, SOT23, Current-Feedback Amplifiers with Shutdown
MAX4223–MAX4228
General Description Features
The MAX4223–MAX4228 current-feedback amplifiers combine ultra-high-speed performance, low distortion, and excellent video specifications with low-power oper- ation. The MAX4223/MAX4224/MAX4226/MAX4228
have a shutdown feature that reduces power-supply current to 350µA and places the outputs into a high- impedance state. These devices operate with dual sup- plies ranging from ± 2.85V to ± 5.5V and provide a typical output drive current of 80mA. The MAX4223/ MAX4225/MAX4226 are optimized for a closed-loop gain of +1 (0dB) or more and have a -3dB bandwidth of 1GHz, while the MAX4224/MAX4227/MAX4228 are compensated for a closed-loop gain of +2 (6dB) or more, and have a -3dB bandwidth of 600MHz (1.2GHz gain-bandwidth product).
The MAX4223–MAX4228 are ideal for professional video applications, with differential gain and phase errors of 0.01% and 0.02°, 0.1dB gain flatness of 300MHz, and a 1100V/µs slew rate. Total harmonic distortion (THD) of
-60dBc (10MHz) and an 8ns settling time to 0.1% suit these devices for driving high-speed analog-to-digital inputs or for data-communications applications. The low- power shutdown mode on the MAX4223/MAX4224/ MAX4226/MAX4228 makes them suitable for portable and battery-powered applications. Their high output impedance in shutdown mode is excellent for multiplex- ing applications.
Ultra-High Speed and Fast Settling Time: 1GHz -3dB Bandwidth (MAX4223, Gain = +1)
600MHz -3dB Bandwidth (MAX4224, Gain = +2) 1700V/µs Slew Rate (MAX4224)
5ns Settling Time to 0.1% (MAX4224)
Excellent Video Specifications (MAX4223): Gain Flatness of 0.1dB to 300MHz 0.01%/0.02° DG/DP Errors
Low Distortion:
-60dBc THD (fc = 10MHz)
42dBm Third-Order Intercept (f = 30MHz)
6.0mA Quiescent Supply Current (per amplifier)
Shutdown Mode:
350µA Supply Current (per amplifier) 100k Output Impedance
High Output Drive Capability: 80mA Output Current
Drives up to 4 Back-Terminated 75 Loads to
±2.5V while Maintaining Excellent Differential Gain/Phase Characteristics
Available in Tiny 6-Pin SOT23 and 10-Pin µMAX Packages
The single MAX4223/MAX4224 are available in space- Ordering Information
PART | TEMP. RANGE | PIN- PACKAGE | SOT TOP MARK | |
MAX4223EUT-T | -40°C to | +85°C | 6 SOT23 | AAAD |
MAX4223ESA | -40°C to | +85°C | 8 SO | — |
saving 6-pin SOT23 packages. All devices are available
in the extended -40°C to +85°C temperature range.
Applications
ADC Input Buffers Data Communications
Video Cameras Video Line Drivers
Video Switches Video Multiplexing
Video Editors XDSL Drivers
Ordering Information continued at end of data sheet.
RF Receivers Differential Line Drivers Selector Guide
PART | MIN. GAIN | AMPS PER PKG. | SHUT- DOWN MODE | PIN- PACKAGE |
MAX4223 | 1 | 1 | Yes | 6 SOT23, 8 SO |
MAX4224 | 2 | 1 | Yes | 6 SOT23, 8 SO |
MAX4225 | 1 | 2 | No | 8 SO |
MAX4226 | 1 | 2 | Yes | 10 µMAX, 14 SO |
MAX4227 | 2 | 2 | No | 8 SO |
MAX4228 | 2 | 2 | Yes | 10 µMAX, 14 SO |
Pin Configurations
TOPVIEW OUT 1 6 VCC VEE 2 5 SHDN IN+ 3 4 IN- Pin Configurations MAX4223 continued at end MAX4224 of data sheet. SOT23-6 |
Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 For small orders, phone 408-737-7600 ext. 3468.
Supply Voltage (VCC to VEE) ..................................................12V Analog Input Voltage .......................(VEE - 0.3V) to (VCC + 0.3V) Analog Input Current ........................................................±25mA SHDN Input Voltage.........................(VEE - 0.3V) to (VCC + 0.3V)
Short-Circuit Duration
OUT to GND ...........................................................Continuous
OUT to VCC or VEE............................................................5sec
Continuous Power Dissipation (TA = +70°C)
6-Pin SOT23 (derate 7.1mW/°C above +70°C).............571mW
8-Pin SO (derate 5.9mW/°C above +70°C)...................471mW
10-Pin µMAX (derate 5.6mW/°C above +70°C) ............444mW
14-Pin SO (derate 8.3mW/°C above +70°C).................667mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
(VCC = +5V, VEE = -5V, SHDN = 5V, VCM = 0V, RL = , TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER | SYMBOL | CONDITIONS | MIN | TYP | MAX | UNITS | |
Input Offset Voltage | VOS | TA = +25°C | MAX4223/MAX4224 | ±0.5 | ±4 | mV | |
MAX4225–MAX4228 | ±0.5 | ±5 | |||||
TA = TMIN to TMAX | MAX4223/MAX4224 | ±6 | |||||
MAX4225–MAX4228 | ±7 | ||||||
Input Offset Voltage Drift | TCVOS | ±2 | µV/°C | ||||
Input Bias Current (Positive Input) | IB+ | TA = +25°C | ±2 | ±10 | µA | ||
TA = TMIN to TMAX | ±15 | ||||||
Input Bias Current (Negative Input) | IB- | TA = +25°C | MAX4223/MAX4224 | ±4 | ±20 | µA | |
MAX4225–MAX4228 | ±4 | ±25 | |||||
TA = TMIN to TMAX | MAX4223/MAX4224 | ±30 | |||||
MAX4225–MAX4228 | ±35 | ||||||
Input Resistance (Positive Input) | RIN+ | 700 | k | ||||
Input Resistance (Negative Input) | RIN- | 45 | | ||||
Input Common-Mode Voltage Range | VCM | Inferred from CMRR test | ±2.5 | ±3.2 | V | ||
Common-Mode Rejection Ratio | CMRR | VCM = ±2.5V | TA = +25°C | 55 | 61 | dB | |
TA = TMIN to TMAX | 50 | ||||||
Operating Supply Voltage Range | VCC/VEE | Inferred from PSRR test | ±2.85 | ±5.5 | V | ||
Power-Supply Rejection Ratio | PSRR | VCC = 2.85V to 5.5V, VEE = -2.85V to -5.5V | TA = +25°C | 68 | 74 | dB | |
TA = TMIN to TMAX | 63 | ||||||
Quiescent Supply Current (per Amplifier) | ISY | Normal mode (SHDN = 5V) | 6.0 | 9.0 | mA | ||
Shutdown mode (SHDN = 0V) | 0.35 | 0.55 | |||||
Open-Loop Transresistance | TR | VOUT = ±2.5V | RL = | 0.7 | 1.5 | M | |
RL = 50 | 0.3 | 0.8 | |||||
Output Voltage Swing | VOUT | RL = 50 | ±2.5 | ±2.8 | V | ||
Output Current (Note 2) | IOUT | VOUT = ±2.5V | 60 | 80 | mA | ||
Short-Circuit Output Current | ISC | RL = short to ground | 140 | mA | |||
SHDN Logic Low | VIL | 0.8 | V | ||||
SHDN Logic High | VIH | 2.0 | V |
(VCC = +5V, VEE = -5V, SHDN = 5V, VCM = 0V, RL = , TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER | SYMBOL | CONDITIONS | MIN TYP MAX | UNITS |
SHDN Input Current | IIL/IIH | SHDN = 0V or 5V | 25 70 | µA |
Shutdown Mode Output Impedance | SHDN = 0V, VOUT = -2.5V to +2.5V (Note 3) | 10 100 | k |
(VCC = +5V, VEE = -5V, SHDN = 5V, VCM = 0V, AV = +1V/V for MAX4223/MAX4225/MAX4226, AV = +2V/V for MAX4224/MAX4227/
MAX4228, RL = 100, TA = +25°C, unless otherwise noted.) (Note 4)
PARAMETER | SYMBOL | CONDITIONS | MIN | TYP | MAX | UNITS | ||
-3dB Small-Signal Bandwidth (Note 5) | BW | VOUT = 20mVp-p | MAX4223/5/6 | 750 | 1000 | MHz | ||
MAX4224/7/8 | 325 | 600 | ||||||
Bandwidth for ±0.1dB Gain Flatness (Note 5) | BW0.1dB | VOUT = 20mVp-p | MAX4223/5/6 | 100 | 300 | MHz | ||
MAX4224/7/8 | 60 | 200 | ||||||
Gain Peaking | MAX4223/5/6 | 1.5 | dB | |||||
MAX4224/7/8 | 0.1 | |||||||
Large-Signal Bandwidth | BWLS | VOUT = 2Vp-p | MAX4223/5/6 | 250 | MHz | |||
MAX4224/7/8 | 330 | |||||||
Slew Rate (Note 5) | SR | VOUT = 4V step | Rising edge | MAX4223/5/6 | 850 | 1100 | V/µs | |
MAX4224/7/8 | 1400 | 1700 | ||||||
Falling edge | MAX4223/5/6 | 625 | 800 | |||||
MAX4224/7/8 | 1100 | 1400 | ||||||
Settling Time to 0.1% | tS | VOUT = 2V step | MAX4223/5/6 | 8 | ns | |||
MAX4224/7/8 | 5 | |||||||
Rise and Fall Time | tr, tf | VOUT = 2V step | MAX4223/5/6 | 1.5 | ns | |||
MAX4224/7/8 | 1.0 | |||||||
Off Isolation | SHDN = 0V, f = 10MHz, MAX4223/4/6/8 | 65 | dB | |||||
Crosstalk | XTALK | f = 30MHz, RS = 50 | MAX4225/6 | -68 | dB | |||
MAX4227/8 | -72 | |||||||
Turn-On Time from Shutdown | tON | MAX4223/4/6/8 | 2 | µs | ||||
Turn-Off Time to Shutdown | tOFF | MAX4223/4/6/8 | 300 | ns | ||||
Power-Up Time | tUP | VCC, VEE = 0V to ±5V step | 100 | ns | ||||
Differential Gain Error | DG | RL = 150 (Note 6) | MAX4223/5/6 | 0.01 | % | |||
MAX4224/7/8 | 0.02 | |||||||
Differential Phase Error | DP | RL = 150 (Note 6) | MAX4223/5/6 | 0.02 | degrees | |||
MAX4224/7/8 | 0.01 | |||||||
Total Harmonic Distortion | THD | VOUT = 2Vp-p, fC = 10MHz | RL = 100 | MAX4223/5/6 | -60 | dBc | ||
MAX4224/7/8 | -61 | |||||||
RL = 1k | MAX4223/5/6 | -65 | ||||||
MAX4224/7/8 | -78 |
(VCC = +5V, VEE = -5V, SHDN = 5V, VCM = 0V, AV = +1V/V for MAX4223/MAX4225/MAX4226, AV = +2V/V for MAX4224/MAX4227/
MAX4228, RL = 100, TA = +25°C, unless otherwise noted.) (Note 4)
PARAMETER | SYMBOL | CONDITIONS | MIN TYP MAX | UNITS | |
Output Impedance | ZOUT | f = 10kHz | 2 | | |
Third-Order Intercept | IP3 | f = 30kHz fz = 30.1MHz | MAX4223/5/6 | 42 | dBm |
MAX4224/7/8 | 36 | ||||
Spurious-Free Dynamic Range | SFDR | f = 10kHz | MAX4223/5/6 | -61 | dB |
MAX4224/7/8 | -62 | ||||
1dB Gain Compression | f = 10kHz | 20 | dBm | ||
Input Noise Voltage Density | en | f = 10kHz | 2 | nV/Hz | |
Input Noise Current Density | in+, in- | f = 10kHz | IN+ | 3 | pA/Hz |
IN- | 20 | ||||
Input Capacitance (Note 7) | CIN | SO-8, SO-14 packages | Pin to pin | 0.3 | pF |
Pin to GND | 1.0 | ||||
SOT23-6, 10-pin µMAX packages | Pin to pin | 0.3 | |||
Pin to GND | 0.8 |
Note 1: The MAX422_EUT is 100% production tested at TA = +25°C. Specifications over temperature limits are guaranteed by design.
Note 2: Absolute Maximum Power Dissipation must be observed.
Note 3: Does not include impedance of external feedback resistor network.
Note 4: AC specifications shown are with optimal values of RF and RG. These values vary for product and package type, and are tabulated in the Applications Information section of this data sheet.
Note 5: The AC specifications shown are not measured in a production test environment. The minimum AC specifications given are based on the combination of worst-case design simulations along with a sample characterization of units. These minimum specifications are for design guidance only and are not intended to guarantee AC performance (see AC Testing/ Performance). For 100% testing of these parameters, contact the factory.
Note 6: Input Test Signal: 3.58MHz sine wave of amplitude 40IRE superimposed on a linear ramp (0IRE to 100IRE). IRE is a unit of video signal amplitude developed by the International Radio Engineers. 140IRE = 1V.
Note 7: Assumes printed circuit board layout similar to that of Maxim’s evaluation kit.
(VCC = +5V, VEE = -5V, RL = 100, TA = +25°C, unless otherwise noted.)
MAX4223
SMALL-SIGNALGAIN vs. FREQUENCY (AVCL= +1)
MAX4223-01
VIN=20mVp-p | |||||||||||||
S | O- | 8PAC | K | AG | E | ||||||||
R | F= | 560 | | ||||||||||
SOT2 | 3- | 6 | |||||||||||
RF= | 47 | 0 | |||||||||||
4
3
2
1
GAIN(dB)
0
-1
-2
-3
-4
-5
-6
MAX4223
SMALL-SIGNALGAIN vs. FREQUENCY (AVCL= +2/+5)
VIN=20mVp-p
MAX4223-02
4
3
Ω
00
/V
=2
2V
G
AV=+
RF=R
NORMALIZEDGAIN(dB)
2
1
0
-1
V/V
0
+5
10
-2 AV=
25
G=
R
-3 RF=
-4
-5
-6
MAX4223/MAX4225/MAX4226 LARGE-SIGNALGAIN vs. FREQUENCY
(AVCL= +1)
MAX4223-03
4
3 AV=+1V/V RF=560
2 VOUT=2Vp-p
1
GAIN(dB)
0
-1
-2
-3
-4
-5
-6
1 10
100 1000
1 10
100 1000
1 10
100 1000
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, RL = 100, TA = +25°C, unless otherwise noted.)
MAX4224
SMALL-SIGNALGAIN vs. FREQUENCY (AVCL= +2)
VIN=20mVp-p
MAX4223-04
4
3
NORMALIZEDGAIN(dB)
2
1
0
-1
E
G
ACKA
O-
S
-2
=470
8P
RG
F=
R
-3
GE
CKA
PA
3-6
T2
SO
-4
0
47
G=
=R
RF
-5
-6
MAX4224
SMALL-SIGNALGAIN vs. FREQUENCY (AVCL= +5/+10)
Vp-p
0m
=2
N
VI
MAX4223-05
4
/V
+5V
L=
VC
A
3
0
NORMALIZEDGAIN(dB)
2 RF=24
1 RG=62
0
-1
-2 AVCL=+10V/V RF=130
-3 RG=15
-4
-5
-6
MAX4224/MAX4227/MAX4228 LARGE-SIGNALGAIN vs. FREQUENCY
(AVCL= +2)
MAX4223-06
4
AVCL=+2V/V
3 RF=RG=470
NORMALIZEDGAIN(dB)
2 VOUT=2Vp-p 1
0
-1
-2
-3
-4
-5
-6
1 10
100 1000
1 10
100 1000
1 10
100 1000
FREQUENCY(MHz)
MAX4225/MAX4226
SMALL-SIGNALGAIN vs. FREQUENCY (AVCL= +1)
MAX4223-07
4
VIN=20mVp-p
3
0.4
0.3
FREQUENCY(MHz)
MAX4225/MAX4226
GAIN MATCHINGvs. FREQUENCY (AVCL= +1)
VIN=2OmVp-p
FREQUENCY(MHz)
MAX4227/MAX4228
SMALL-SIGNALGAIN vs. FREQUENCY (AVCL= +2)
MAX4223-08
MAX4223-09
4
VIN=20mVp-p
3
AVCL=+1V/V
2 RF=560
1
GAIN(dB)
0
-1
-2
-3
-4
-5
-6
1 10
100 1000
0.2
0.1
GAIN(dB)
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
AVCL=+1V/V RF=560
1
AMPLIFIERA
AMPLIFIERB
10 100
AVCL=+2V/V
NORMALIZEDGAIN(dB)
2 RF=RG=470
1
0
-1
-2
-3
-4
-5
-6
1 10
100 1000
0.4
0.3
NORMALIZEDGAIN(dB)
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
FREQUENCY(MHz)
MAX4227/MAX4228
GAIN MATCHINGvs. FREQUENCY (AVCL= +2)
VIN=20mVp-p AVCL=+2V/V RF=RG=470
0
MAX4223-10
-10
-20
CROSSTALK(dB)
-30
-40
-50
-60
-70
-80
-90
-100
FREQUENCY(MHz)
MAX4225/MAX4226 CROSSTALK vs. FREQUENCY
RS=50 VOUT=2Vp-p
0
MAX4223-11
-10
-20
CROSSTALK(dB)
-30
-40
-50
-60
-70
-80
-90
-100
FREQUENCY(MHz)
MAX4223-12
MAX4227/MAX4228 CROSSTALK vs. FREQUENCY
RS=50 VOUT=2Vp-p
0.1 1
10 100
1 10
100 1000
1 10
100 1000
FREQUENCY(MHz)
FREQUENCY(MHz)
FREQUENCY(MHz)
PSRR(dB)
(VCC = +5V, VEE = -5V, RL = 100, TA = +25°C, unless otherwise noted.)
10
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
MAX4223/MAX4225/MAX4226 POWER-SUPPLY REJECTIONRATIO
vs. FREQUENCY (AVCL= +1)
AVCL=+1V/V RF=560
VCC
VEE
10
MAX4223-13
0
-10
-20
PSRR(dB)
-30
-40
-50
-60
-70
-80
-90
MAX4224/MAX4227/MAX4228 POWER-SUPPLY REJECTIONRATIO
vs. FREQUENCY (AVCL= +2)
AVCL=+2V/V RF=RG=470
VCC
VEE
100
MAX4223-14
OUTPUTIMPEDANCE( )
10
1
0.1
0.01
OUTPUT IMPEDANCE vs. FREQUENCY
MAX4223-15
MAX4223/5/6 AVCL=+1V/V RF=560
MAX4224/7/8 AVCL=+2V/V RF=RG=470
0.01
0.1
1 10 100
FREQUENCY(MHz)
0.01
0.1
1 10 100
FREQUENCY(MHz)
0.01 0.1 1 10 100
FREQUENCY(MHz)
SHUTDOWNMODEOUTPUTISOLATION(dB)
20
0
-20
SHUTDOWN MODEOUTPUT ISOLATION vs. FREQUENCY
MAX4223-16
MAX4223/5/6 AVCL=+1V/V
-30
-40
MAX4223/MAX4225/MAX4226 TOTALHARMONICDISTORTION vs. FREQUENCY (RL = 150)
AVCL=+1V/V RL=150 RF=560
-30
MAX4223-17
-40
MAX4223/MAX4225/MAX4226 TOTALHARMONICDISTORTION vs. FREQUENCY (RL = 1k)
MAX4223-18
AVCL=+1V/V
RL=1k RF=560
-40
-60
-80
-100
RF=560
MAX4224/7/8
-50
THD(dBc)
-60
VOUT=2Vp-p
THD
-50
THD(dBc)
-60
-70
VOUT=2Vp-p
THD
-120
-140
-160
-180
AVCL=+2V/V RF=RG=470
-70
-80
-90
2NDHARMONIC
3RDHARMONIC
-80
-90
-100
2NDHARMONIC 3RDHARMONIC
0.01
0.1 1
10 100
1000
0.1 1
10 100
0.1 1
10 100
-30
-40
THD(dBc)
-50
-60
-70
FREQUENCY(MHz)
MAX4224/MAX4227/MAX4228 TOTALHARMONICDISTORTION vs. FREQUENCY (RL = 150)
D
T
H
-30
MAX4223-19
-40
-50
THD(dBc)
-60
-70
-80
FREQUENCY(MHz)
MAX4224/MAX4227/MAX4228 TOTALHARMONICDISTORTION vs. FREQUENCY (RL = 1k)
THD
2NDHARMONIC
FREQUENCY(MHz)
TWO-TONE THIRD-ORDER INTERCEPT vs. FREQUENCY
MAX4223-20
MAX4223-21
55
THIRD-ORDERINTERCEPT(dBm)
50
45
40 MAX4224/7/8
35
30
-80
2NDHARMONIC
3RDHARMONIC
-90
MAX4223/5/6
3RDHARMONIC
25
-90
0.1 1
10 100
-100
0.1 1
10 100
20
10 20
30 40
50 60 70 80 90 100
(VCC = +5V, VEE = -5V, RL = 100, TA = +25°C, unless otherwise noted.)
+100mV INPUT
-100mV
+100mV OUTPUT
-100mV
MAX4223/MAX4225/MAX4226 SMALL-SIGNAL PULSERESPONSE
(AVCL= +1)
MAX4223-22
GND
GND
+100mV INPUT
-100mV
+100mV OUTPUT
-100mV
MAX4223/MAX4225/MAX4226 SMALL-SIGNAL PULSERESPONSE
(AVCL= +1, CL= 25pF)
MAX4223-23
GND
GND
+50mV INPUT
-50mV
+100mV OUTPUT
-100mV
MAX4224/MAX4227/MAX4228 SMALL-SIGNAL PULSERESPONSE
(AVCL= +2)
MAX4223-24
GND
GND
TIME(10ns/div)
TIME(10ns/div)
TIME(10ns/div)
MAX4224/MAX4227/MAX4228 SMALL-SIGNAL PULSERESPONSE
(AVCL= +2, CL= 10pF)
MAX4223-25
MAX4223/MAX4225/MAX4226 LARGE-SIGNAL PULSERESPONSE
(AVCL= +1)
MAX4223-26
MAX4223/MAX4225/MAX4226 LARGE-SIGNAL PULSERESPONSE
(AVCL= +1, CL= 25pF)
MAX4223-27
+50mV INPUT
-50mV
GND
+2V INPUT
-2V
GND
+2V INPUT
-2V
GND
+100mV OUTPUT
-100mV
GND
+2V OUTPUT
-2V
+2V GND OUTPUT
-2V
GND
TIME(10ns/div)
TIME(10ns/div)
TIME(10ns/div)
MAX4224/MAX4227/MAX4228 LARGE-SIGNAL PULSERESPONSE
(AVCL= +2)
MAX4223-28
MAX4224/MAX4227/MAX4228 LARGE-SIGNAL PULSERESPONSE
(AVCL= +2,CL = 10pF)
MAX4223-29
MAX4224/MAX4227/MAX4228 LARGE-SIGNAL PULSERESPONSE
(AVCL= +5)
MAX4223-30
+1V INPUT
-1V
GND
+1V INPUT
-1V
GND
+400mV INPUT
-400mV
GND
+2V OUTPUT
-2V
GND
+2V OUTPUT
-2V
+2V GND OUTPUT
-2V
GND
TIME(10ns/div)
TIME(10ns/div)
TIME(10ns/div)
CURRENT(mA)
(VCC = +5V, VEE = -5V, RL = 100, TA = +25°C, unless otherwise noted.)
POWER-SUPPLY CURRENT PERAMPLIFIER vs. TEMPERATURE
MAX4223-31
8 5
7
NORMAL 4
6 MODE
CURRENT( A)
5 3
4
3 2
2
SHUTDOWN 1
1 MODE
0 0
MAX4223-32
INPUT BIASCURRENT vs. TEMPERATURE
IB-
170
CURRENT(mA)
160
150
140
130
120
MAX4223-33
SHORT-CIRCUITOUTPUT CURRENT vs. TEMPERATURE
SINKING | |||||
SOURCING | |||||
IB+
-50
-25 0
25 50 75 100
-50
-25 0
25 50 75 100
-50
-25 0
25 50 75 100
TEMPERATURE(°C)
POSITIVEOUTPUT SWING vs. TEMPERATURE
MAX4223-34
RL=OPEN | |||||
RL=50 | |||||
4.5
POSITIVEOUTPUTSWING(V)
4.0
3.5
3.0
2.5
2.0
1.5
TEMPERATURE(°C)
-1.0
NEGATIVEOUTPUTSWING(V)
-1.5
-2.0
-2.5
-3.0
-3.5
-4.0
TEMPERATURE(°C)
MAX4223-35
RL=50 | |||||
RL=OPEN | |||||
NEGATIVEOUTPUT SWING vs. TEMPERATURE
1.0
-50
-25
0 25
50 75 100
-4.5
-50
-25
0 25
50 75 100
TEMPERATURE(°C) TEMPERATURE(°C)
PIN | NAME | FUNCTION FUNCTION | ||||
MAX4223/MAX4224 | MAX4225 MAX4227 | MAX4226/MAX4228 | ||||
SOT23 | SO | SO | µMAX | SO | ||
— | 1, 5 | — | — | 5, 7, 8, 10 | N.C. | No Connect. Not internally connected. Tie to GND for optimum AC performance. |
1 | 6 | — | — | — | OUT | Amplifier Output |
2 | 4 | 4 | 4 | 4 | VEE | Negative Power-Supply Voltage. Connect to -5V. |
3 | 3 | — | — | — | IN+ | Amplifier Noninverting Input |
4 | 2 | — | — | — | IN- | Amplifier Inverting Input |
5 | 8 | — | — | — | SHDN | Amplifier Shutdown. Connect to +5V for normal operation. Connect to GND for low- power shutdown. |
6 | 7 | 8 | 10 | 14 | VCC | Positive Power-Supply Voltage. Connect to +5V. |
— | — | 1 | 1 | 1 | OUTA | Amplifier A Output |
— | — | 2 | 2 | 2 | INA- | Amplifier A Inverting Input |
— | — | 3 | 3 | 3 | INA+ | Amplifier A Noninverting Input |
— | — | 5 | 7 | 11 | INB+ | Amplifier B Noninverting Input |
— | — | 6 | 8 | 12 | INB- | Amplifier B Inverting Input |
— | — | 7 | 9 | 13 | OUTB | Amplifier B Output |
— | — | — | 5 | 6 | SHDNA | Amplifier A Shutdown Input. Connect to +5V for normal operation. Connect to GND for low-power shutdown mode. |
— | — | — | 6 | 9 | SHDNB | Amplifier B Shutdown Input. Connect to +5V for normal operation. Connect to GND for low-power shutdown mode. |
RG RF IN- RIN- TZ OUT +1 +1 IN+ MAX4223 VIN MAX4224 MAX4225 MAX4226 MAX4227 MAX4228 |
The MAX4223–MAX4228 are ultra-high-speed, low- power, current-feedback amplifiers featuring -3dB bandwidths up to 1GHz, 0.1dB gain flatness up to 300MHz, and very low differential gain and phase errors of 0.01% and 0.02°, respectively. These devices operate on dual ± 5V or ± 3V power supplies and require only 6mA of supply current per amplifier. The MAX4223/MAX4225/MAX4226 are optimized for closed-loop gains of +1 (0dB) or more and have -3dB bandwidths of 1GHz. The MAX4224/MAX4227/ MAX4228 are optimized for closed-loop gains of +2 (6dB) or more, and have -3dB bandwidths of 600MHz (1.2GHz gain-bandwidth product).
The current-mode feedback topology of these ampli- fiers allows them to achieve slew rates of up to 1700V/µs with corresponding large signal bandwidths up to 330MHz. Each device in this family has an output that is capable of driving a minimum of 60mA of output current to ±2.5V.
Theory of Operation Since the MAX4223–MAX4228 are current-feedback amplifiers, their open-loop transfer function is expressed as a transimpedance:
Figure 1. Current-Feedback Amplifier
Low-Power Shutdown Mode
VOUT
IIN
or TZ
The MAX4223/MAX4224/MAX4226/MAX4228 have a
shutdown mode that is activated by driving the SHDN
input low. When powered from ±5V supplies, the SHDN
The frequency behavior of this open-loop transimped- ance is similar to the open-loop gain of a voltage-feed- back amplifier. That is, it has a large DC value and decreases at approximately 6dB per octave.
Analyzing the current-feedback amplifier in a gain con- figuration (Figure 1) yields the following transfer func- tion:
input is compatible with TTL logic. Placing the amplifier in shutdown mode reduces quiescent supply current to 350µA typical, and puts the amplifier output into a high- impedance state (100k typical). This feature allows these devices to be used as multiplexers in wideband systems. To implement the mux function, the outputs of multiple amplifiers can be tied together, and only the amplifier with the selected input will be enabled. All of
VOUT VIN
G x
TZS
TZS G x RIN
RF
RF
the other amplifiers will be placed in the low-power shutdown mode, with their high output impedance pre- senting very little load to the active amplifier output. For gains of +2 or greater, the feedback network imped-
where G AV
1 . RG
ance of all the amplifiers used in a mux application must be considered when calculating the total load on the active amplifier output.
At low gains, (G x RIN-) << RF . Therefore, unlike tradi-
tional voltage-feedback amplifiers, the closed-loop bandwidth is essentially independent of the closed- loop gain. Note also that at low frequencies, TZ >> [(G x RIN-) + RF], so that:
Layout and Power-Supply Bypassing The MAX4223–MAX4228 have an extremely high band- width, and consequently require careful board layout,
VOUT
VIN
G 1 RF
RG
including the possible use of constant-impedance microstrip or stripline techniques.
To realize the full AC performance of these high-speed amplifiers, pay careful attention to power-supply bypassing and board layout. The PC board should have at least two layers: a signal and power layer on one side and a large, low-impedance ground plane on the other. The ground plane should be as free of voids as possible, with one exception: the inverting input pin (IN-) should have as low a capacitance to ground as possible. This means that there should be no ground plane under IN- or under the components (RF and RG) connected to it. With multilayer boards, locate the ground plane on a layer that incorporates no signal or power traces.
Whether or not a constant-impedance board is used, it is best to observe the following guidelines when designing the board:
Do not use wire-wrapped boards (they are too inductive) or breadboards (they are too capacitive).
Do not use IC sockets. IC sockets increase reac- tance.
Keep signal lines as short and straight as possible. Do not make 90° turns; round all corners.
Observe high-frequency bypassing techniques to maintain the amplifier’s accuracy and stability.
In general, surface-mount components have shorter bodies and lower parasitic reactance, giving better high-frequency performance than through-hole com- ponents.
The bypass capacitors should include a 10nF ceramic, surface-mount capacitor between each supply pin and the ground plane, located as close to the package as possible. Optionally, place a 10µF tantalum capacitor at the power-supply pins’ point of entry to the PC board to ensure the integrity of incoming supplies. The power- supply trace should lead directly from the tantalum capacitor to the VCC and VEE pins. To minimize para- sitic inductance, keep PC traces short and use surface- mount components. The N.C. pins should be connected to a common ground plane on the PC board to minimize parasitic coupling.
If input termination resistors and output back-termina- tion resistors are used, they should be surface-mount types, and should be placed as close to the IC pins as possible. Tie all N.C. pins to the ground plane to mini- mize parasitic coupling.
Choosing Feedback and Gain Resistors As with all current-feedback amplifiers, the frequency response of these devices depends critically on the value of the feedback resistor RF. RF combines with an internal compensation capacitor to form the dominant pole in the feedback loop. Reducing RF’s value increases the pole frequency and the -3dB bandwidth, but also increases peaking due to interaction with other nondominant poles. Increasing RF’s value reduces peaking and bandwidth.
Table 1 shows optimal values for the feedback resistor (RF) and gain-setting resistor (RG) for the MAX4223– MAX4228. Note that the MAX4224/MAX4227/MAX4228
offer superior AC performance for all gains except unity gain (0dB). These values provide optimal AC response using surface-mount resistors and good layout tech- niques. Maxim’s high-speed amplifier evaluation kits provide practical examples of such layout techniques.
Stray capacitance at IN- causes feedback resistor decoupling and produces peaking in the frequency- response curve. Keep the capacitance at IN- as low as possible by using surface-mount resistors and by avoiding the use of a ground plane beneath or beside these resistors and the IN- pin. Some capacitance is unavoidable; if necessary, its effects can be counter- acted by adjusting RF. Use 1% resistors to maintain consistency over a wide range of production lots.
GAIN (V/V) | GAIN (dB) | RF () | RG () | -3dB BW (MHz) | 0.1dB BW (MHz) |
MAX4223/MAX4225/MAX4226 | |||||
1 | 0 | 560* | Open | 1000 | 300 |
2 | 6 | 200 | 200 | 380 | 115 |
5 | 14 | 100 | 25 | 235 | 65 |
MAX4224/MAX4227/MAX4228 | |||||
2 | 6 | 470 | 470 | 600 | 200 |
5 | 14 | 240 | 62 | 400 | 90 |
10 | 20 | 130 | 15 | 195 | 35 |
*For the MAX4223EUT, this optimal value is 470.
RG RF IN- IB- OUT VOUT IB+ IN+ MAX4223 MAX4224 RS MAX4225 □ MAX4226 MAX4227 MAX4228 |
DC and Noise Errors The MAX4223–MAX4228 output offset voltage, VOUT (Figure 2), can be calculated with the following equation:
VOUT
VOS x 1 RF/RG IB x RS
where:
x 1
RF
RG
IB x RF
VOS = input offset voltage (in volts)
1 + RF / RG = amplifier closed-loop gain (dimensionless) IB+ = input bias current (in amps)
IB- = inverting input bias current (in amps) RG = gain-setting resistor (in )
RF = feedback resistor (in ) RS = source resistor (in )
The following equation represents output noise density:
Figure 2. Output Offset Voltage
enOUT
1
RF x RG
With a 600MHz system bandwidth, this calculates to 250µVRMS (approximately 1.5mVp-p, using the six- sigma calculation).
where:
n S n
F G n
Communication Systems Nonlinearities of components used in a communication system produce distortion of the desired output signal.
in = input noise current density (in pA/Hz) en = input noise voltage density (in nV/Hz)
The MAX4223–MAX4228 have a very low, 2nV/Hz noise voltage. The current noise at the noninverting input (in+) is 3pA/Hz, and the current noise at the inverting input (in-) is 20pA/Hz.
An example of DC-error calculations, using the MAX4224 typical data and the typical operating circuit with RF = RG = 470 (RF RG = 235) and RS = 50, gives:
VOUT = [5 x 10-4 x (1 + 1)] + [2 x 10-6 x 50 x (1 + 1)] +
[4 x 10-6 x 470]
VOUT = 3.1mV
Calculating total output noise in a similar manner yields the following:
Intermodulation distortion (IMD) is the distortion that results from the mixing of two input signals of different frequencies in a nonlinear system. In addition to the input signal frequencies, the resulting output signal contains new frequency components that represent the sum and difference products of the two input frequen- cies. If the two input signals are relatively close in fre- quency, the third-order sum and difference products will fall close to the frequency of the desired output and will therefore be very difficult to filter. The third-order intercept (IP3) is defined as the power level at which the amplitude of the largest third-order product is equal to the power level of the desired output signal. Higher third-order intercept points correspond to better lineari- ty of the amplifier. The MAX4223–MAX4228 have a typi- cal IP3 value of 42dBm, making them excellent choices for use in communications systems.
enOUT
1 1 x
3
x 1012
x 50 2
ADC Input Buffers Input buffer amplifiers can be a source of significant errors in high-speed ADC applications. The input buffer is usually required to rapidly charge and discharge the
12
2
9 2
ADC’s input, which is often capacitive (see the section
enOUT
20 x 10
10.2nV / Hz
x 235 2
x 10
Driving Capacitive Loads). In addition, a high-speed ADC’s input impedance often changes very rapidly during the conversion cycle, requiring an amplifier with
very low output impedance at high frequencies to main- tain measurement accuracy. The combination of high speed, fast slew rate, low noise, and low distortion makes the MAX4223–MAX4228 ideally suited for use as buffer amplifiers in high-speed ADC applications.
Video Line Driver The MAX4223–MAX4228 are optimized to drive coaxial transmission lines when the cable is terminated at both ends, as shown in Figure 3. Note that cable frequency response may cause variations in the signal’s flatness.
Driving Capacitive Loads A correctly terminated transmission line is purely resis- tive and presents no capacitive load to the amplifier. Although the MAX4223–MAX4228 are optimized for AC performance and are not designed to drive highly capacitive loads, they are capable of driving up to 25 pF without excessive ringing. Reactive loads decrease phase margin and may produce excessive ringing and oscillation (see Typical Operating Characteristics). Figure 4’s circuit reduces the effect of large capacitive loads. The small (usually 5 to 20) isolation resistor RISO, placed before the reactive load, prevents ringing and oscillation at the expense of a
small gain error. At higher capacitive loads, AC perfor- mance is limited by the interaction of load capacitance with the isolation resistor.
Maxim’s High-Speed Evaluation Board Layout
Figures 7 and 8 show a suggested layout for Maxim’s high-speed, single-amplifier evaluation boards. These boards were developed using the techniques described above. The smallest available surface-mount resistors were used for the feedback and back-termination resis- tors to minimize the distance from the IC to these resis- tors, thus reducing the capacitance associated with longer lead lengths.
SMA connectors were used for best high-frequency performance. Because distances are extremely short, performance is unaffected by the fact that inputs and outputs do not match a 50 line. However, in applica- tions that require lead lengths greater than 1/4 of the wavelength of the highest frequency of interest, con- stant-impedance traces should be used.
Fully assembled evaluation boards are available for the MAX4223 in an SO-8 package.
RG RF IN- RT 75 75 CABLE OUT 75 CABLE IN+ RT MAX4223 75 RT MAX4224 75 MAX4225 □ MAX4226 □ MAX4227 MAX4228 |
RG RF IN- OUT RISO IN+ CL RL MAX4223 MAX4224 MAX4225 MAX4226 MAX4227 MAX4228 |
Figure 3. Video Line Driver
Figure 4. Using an Isolation Resistor (RISO) for High Capacitive Loads
MAX4223-fig5a
AC Testing/Performance AC specifications on high-speed amplifiers are usually guaranteed without 100% production testing. Since these high-speed devices are sensitive to external par- asitics introduced when automatic handling equipment is used, it is impractical to guarantee AC parameters through volume production testing. These parasitics are greatly reduced when using the recommended PC board layout (like the Maxim evaluation kit). Characterizing the part in this way more accurately rep- resents the amplifier’s true AC performance. Some
manufacturers guarantee AC specifications without clearly stating how this guarantee is made. The MAX4223–MAX4228 AC specifications are derived from worst-case design simulations combined with a sample characterization of 100 units. The AC perfor- mance distributions along with the worst-case simula- tion limits are shown in Figures 5 and 6. These distributions are repeatable provided that proper board layout and power-supply bypassing are used (see Layout and Power-Supply Bypassing section).
50
100UNITS
NUMBEROFUNITS
40
30 SIMULATION LOWERLIMIT
20
50
MAX4223-fig5b
100UNITS
NUMBEROFUNITS
40
30 SIMULATION LOWERLIMIT
20
10 10
0–600
650–700
750–800
850–900
950–1000
1050–1100
1150–1200
1250–1300
1350–1400
1450–1500
0–60
80–100
120–140
160–180
200–220
240–260
280–300
320–340
360–380
400–420
0 0
-3dBBANDWIDTH(MHz) ±0.1dBBANDWIDTH(MHz)
MAX4223-fig5c
Figure 5a. MAX4223 -3dB Bandwidth Distribution
Figure 5b. MAX4223 ±0.1dB Bandwidth Distribution
50
100UNITS
NUMBEROFUNITS
40
30 SIMULATION LOWERLIMIT
20
50
MAX4223-fig5d
100UNITS
NUMBEROFUNITS
40
30 SIMULATION LOWERLIMIT
20
10 10
0–800
825–850
875–900
925–950
975–1000
1025–1050
1075–1100
1125–1150
1175–1200
1225–1250
0–500
525–550
575–600
625–650
675–700
725–750
775–800
825–850
875–900
925–950
0 0
RISING-EDGESLEWRATE(V/s)
Figure 5c. MAX4223 Rising-Edge Slew-Rate Distribution
FALLING-EDGESLEWRATE(V/ s)
Figure 5d. MAX4223 Falling-Edge Slew-Rate Distribution
MAX4223-fig6a
MAX4223-fig6b
100UNITS | ||||||||||||||
SIMULATION LOWERLIMIT | ||||||||||||||
50 50
100UNITS
NUMBEROFUNITS
NUMBEROFUNITS
40 40
30 SIMULATION 30
LOWERLIMIT
20 20
10 10
0–200
250–300
350–400
450–500
550–600
650–700
750–800
850–900
950–1000
1050–1100
0–40
60–80
100–120
140–160
180–200
220–240
260–280
300–320
340–360
380–400
0 0
-3dBBANDWIDTH(MHz) ±0.1dBBANDWIDTH(MHz)
MAX4223-fig6c
Figure 6a. MAX4224 -3dB Bandwidth Distribution
Figure 6b. MAX4224 ±0.1dB Bandwidth Distribution
50
100UNITS
NUMBEROFUNITS
40
30 SIMULATION LOWERLIMIT
20
50
MAX4223-fig6d
100UNITS
NUMBEROFUNITS
40
30 SIMULATION LOWERLIMIT
20
10 10
0–1400
1425–1450
1475–1500
1525–1550
1575–1600
1625–1650
1675–1700
1725–1750
1775–1800
1825–1850
0–1100
1125–1150
1175–1200
1225–1250
1275–1300
1325–1350
1375–1400
1425–1450
1475–1500
1525–1550
0 0
RISING-EDGESLEWRATE(V/s)
Figure 6c. MAX4224 Rising-Edge Slew-Rate Distribution
FALLING-EDGESLEWRATE(V/ s)
Figure 6d. MAX4224 Falling-Edge Slew-Rate Distribution
Figure 7a. Maxim SOT23 High-Speed Evaluation Board Component Placement Guide—Component Side
Figure 7b. Maxim SOT23 High-Speed Evaluation Board PC Board Layout—Component Side
Figure 7c. Maxim SOT23 High-Speed Evaluation Board PC Board Layout—Back Side
Figure 8a. Maxim SO-8 High-Speed Evaluation Board Component Placement Guide—Component Side
Figure 8b. Maxim SO-8 High-Speed Evaluation Board PC Board Layout—Component Side
Figure 8c. Maxim SO-8 High-Speed Evaluation Board PC Board Layout—Back Side
14 VCC
13 OUTB
12 INB-
11 INB+
10 N.C.
9 SHDNB
8 N.C.
OUTA 1
INA- 2
INA+ 3
VEE 4
N.C. 5 SHDNA 6
N.C. 7
MAX
TOPVIEW
MAX4223 MAX4224
MAX4225 MAX4227
N.C. 1
8 SHDN
OUTA 1
8 VCC
IN- 2
7 VCC
INA- 2
7 OUTB
IN+ 3
6 OUT
INA+ 3
6 INB-
VEE 4
5 N.C.
VEE 4
5 INB+
SO
SO
MAX4226 MAX4228
MAX4226 MAX4228
OUTA 1
INA- 2
INA+ 3
VEE 4
SHDNA 5
10 VCC
9 OUTB
8 INB-
7 INB+
6 SHDNB
SO
_Ordering Infor mation (continued)
PART | TEMP. RANGE | PIN- PACKAGE | SOT TOP MARK | |
MAX4224EUT-T | -40°C to | +85°C | 6 SOT23 | AAAE |
MAX4224ESA | -40°C to | +85°C | 8 SO | — |
MAX4225ESA | -40°C to | +85°C | 8 SO | — |
MAX4226EUB | -40°C to | +85°C | 10 µMAX | — |
MAX4226ESD | -40°C to | +85°C | 14 SO | — |
MAX4227ESA | -40°C to | +85°C | 8 SO | — |
MAX4228EUB | -40°C to | +85°C | 10 µMAX | — |
MAX4228ESD | -40°C to | +85°C | 14 SO | — |
MAX4223/MAX4224 TRANSISTOR COUNT: 87 MAX4225–MAX4228 TRANSISTOR COUNT: 171 SUBSTRATE CONNECTED TO VEE
MAX4223–MAX4228
10LUMAXB.EPS
Package Infor mation
6LSOT.EPS
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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