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EVALUATION KIT AVAILABLE
The MAX40242 provides a combination of high voltage, low noise, low input bias current in a dual channel and features rail-to-rail at the output.
This dual amplifier operates over a wide supply voltage range from a single 2.7V to 20V supply or split ±1.35V to ±10V supplies and consumes only 1.2mA quiescent supply current per channel.
The MAX40242 is a unity-gain stable amplifier with a gain-bandwidth product of 10MHz. The device outputs drive up to 200pF load capacitor without any external isolation resistor compensation.
The MAX40242 is available in 8-thin wafer-level packages (WLPs) and is rated for operation over the
-40°C to +125°C automotive temperature range.
Chemical Sensor Interface
Photodiode Sensor Interface
Medical Pulse Oximetry
Industrial: Process and Control
Precision Instrumentation
2.7V to 20V Single Supply or ±1.35V to ±10V Dual Supplies
2pA (Max) Input Bias Current
5nV/√Hz Input Voltage Noise
10MHz Bandwidth
8V/µs Slew Rate
Rail-to-Rail Output
Integrated EMI Filters
1.2mA Supply Current per Amplifier
Tiny, 0.85mm x 1.65mm 8-WLP
Ordering Information appears at end of data sheet.
VDD
PHOTODIODE
IN-
OUT
PHOTODIODE
IN+
IN-
REF
OUT
IN+
MAX40242
REF
19-100357 Rev 0; 6/18
Supply Voltage (VDD to VSS) ................................-0.3V to +22V
All Other Pins ................................ (VSS - 0.3V) to (VDD + 0.3V)
Short-Circuit Duration to VDD or VSS...................................... 1s
Continuous Input Current (Any Pins) ...............................±20mA
Differential Input Voltage ...................................................... ±6V
Continuous Power Dissipation (TA = +70°C)
8-THIN WLP (derate 11.4mW/°C above +70°C) .........912mW
Operating Temperature Range......................... -40°C to +125°C Junction Temperature ...................................................... +150°C
Storage Temperature Range ............................ -65°C to +150°C
Lead Temperature (soldering, 10s) ................................. +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.
8-THIN WLP
Junction-to-Ambient Thermal Resistance (θJA) .....87.71°C/W
Junction-to-Case Thermal Resistance (θJC) ..............NA°C/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
(VDD = 10V, VSS = 0V, VIN+ = VIN- = VDD/2, RL = 10kΩ to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER | SYMBOL | CONDITIONS | MIN | TYP | MAX | UNITS | |
POWER SUPPLY | |||||||
Supply Voltage Range | VDD | Guaranteed by PSRR | 2.7 | 20 | V | ||
Power-Supply Rejection Ratio | PSRR | VDD = 2.7V to 20V, VCM = 0V | TA = +25ºC | 106 130 | dB | ||
-40ºC ≤ TA ≤ +125ºC | 100 | ||||||
Quiescent Current Per Amplifier | IDD | RLOAD = infinity | TA = +25ºC | 1.2 | 1.6 | mA | |
-40ºC ≤ TA ≤ +125ºC | 1.8 | ||||||
Power-Up Time | tON | RLOAD = 10kΩ to VDD/2, CLOAD = 20pF, VOUT reaches VDD/2 to 1% | 20 | µs | |||
DC CHARACTERISTICS | |||||||
Input Common-Mode Range | VCM | Guaranteed by CMRR test | VSS - 0.05 | VDD - 1.5 | V | ||
Common-Mode Rejection Ratio | CMRR | VCM = VSS - 0.05V to VDD - 1.5V | TA = +25ºC | 94 111 | dB | ||
-40ºC ≤ TA ≤ +125ºC | 90 | ||||||
Input Offset Voltage | VOS | TA = +25ºC | 50 | 600 | µV | ||
-40ºC ≤ TA ≤ +125ºC | 800 | ||||||
Input Offset Voltage Drift (Note 3) | TC VOS | 0.25 | 2.5 | µV/ºC | |||
Input Bias Current (Note 3) | IB | TA = +25ºC | 0.02 2 | pA | |||
-40ºC ≤ TA ≤ +85ºC | 15 | ||||||
-40ºC ≤ TA ≤ +125ºC | 75 |
(VDD = 10V, VSS = 0V, VIN+ = VIN- = VDD/2, RL = 10kΩ to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER | SYMBOL | CONDITIONS | MIN TYP MAX | UNITS | |
Input Offset Current (Note 3) | IOS | TA = +25°C | 0.04 1 | pA | |
-40°C ≤ TA ≤ +85°C | 10 | ||||
-40°C ≤ TA ≤ +125°C | 25 | ||||
Open Loop Gain | AVOL | 250mV ≤ VOUT ≤ VDD - 250mV | TA = +25°C | 134 145 | dB |
-40°C ≤ TA ≤ +125°C | 129 | ||||
Input Resistance | RIN | Differential | 50 | MΩ | |
Common mode | 200 | ||||
Output Short-Circuit Current (Note 3) | To VDD or VSS | Noncontinuous (1s) | 95 | mA | |
Output Voltage Low | VOL | VOUT - VSS, RLOAD = 10KΩ to VDD/2, TA = +25°C | 11 15 | mV | |
VOUT - VSS, RLOAD = 10KΩ to VDD/2, -40°C < TA < 125°C | 25 | ||||
VOUT - VSS, RLOAD = 2KΩ to VDD/2, TA = +25°C | 47 60 | ||||
VOUT - VSS, RLOAD = 2KΩ to VDD/2, -40°C < TA < 125°C | 85 | ||||
Output Voltage High | VOH | VOUT - VSS, RLOAD = 10KΩ to VDD/2, TA = +25°C | 20 26 | mV | |
VOUT - VSS, RLOAD = 10KΩ to VDD/2, -40°C < TA < 125°C | 37 | ||||
VOUT - VSS, RLOAD = 2KΩ to VDD/2, TA = +25°C | 80 100 | ||||
VOUT - VSS, RLOAD = 2KΩ to VDD/2, -40°C < TA < 125°C | 135 | ||||
AC CHARACTERISTICS | |||||
Input Voltage-Noise Density | en | f = 1kHz | 5 | nV/√Hz | |
Input Voltage Noise | 0.1Hz ≤ f ≤ 10Hz | 1.6 | µVP-P | ||
Input Current-Noise Density | IN | f = 1kHz | 0.3 | pA/√Hz | |
Input Capacitance | CIN | 4 | pF | ||
Gain-Bandwidth Product | GBW | 10 | MHz | ||
Phase Margin | PM | CLOAD = 20pF | 60 | ° | |
Slew Rate | SR | AV = 1V/V, VOUT = 2VP-P, 10% to 90% | 8 | V/µs | |
Large-Signal Bandwidth | BW | RLOAD = 10KΩ to VDD/2, CLOAD = 20pF, AV = 1V/V | 1 | MHz | |
Capacitive Loading | CLOAD | No sustained oscillation, AV = 1V/V | 200 | pF | |
Crosstalk | XT | RLOAD = 2KΩ to VDD/2, CLOAD = 20pF, VOUT = 5VP-P, f = 100kHz | -98 | dB |
(VDD = 10V, VSS = 0V, VIN+ = VIN- = VDD/2, RL = 10kΩ to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER | SYMBOL | CONDITIONS | MIN TYP MAX | UNITS | |
Total Harmonic Distortion Plus Noise | THD+N | VOUT = 2VP-P, AV = +1V/V | f = 1kHz | -124 | dB |
f = 20kHz | -100 | ||||
EMI Rejection Ratio | EMIRR | VRF_PEAK = 100mV | f = 400MHz | 35 | dB |
f = 800MHz | 40 | ||||
f = 1800MHz | 50 | ||||
f = 2400MHz | 57 | ||||
Settling Time | To 0.1%, VOUT = 2V step, AV = -1V/V | 2 | µs |
Note 2: All devices are production tested at TA = +25°C. Specifications over temperature are guaranteed by design.
Note 3: Guaranteed by design.
(VDD = 10V, VSS = 0V, outputs have RL = 10kΩ to VDD/2. TA = +25°C, unless otherwise specified.)
INPUT OFFSET VOLTAGE HISTOGRAM
35 toc01
INPUT OFFSET VOLTAGE DRIFT HISTOGRAM
35 toc02
1800
SUPPLY CURRENT PER AMPLIFIER vs. TEMPERATURE
toc03
HISTOGRAM
30
OCCURRENCE N (%)
25
20
15
10
5
HISTOGRAM
30
OCCURRENCE N (%)
25
20
15
10
5
1500
SUPPLY CURRENT PER AMPLIFIER (μA)
1200
900
600
300
VIN = VDD/2 NO LOAD
VDD = 10V
VDD = 20V
VDD = 15V
VDD = 5.5V
VDD = 2.7V
0
-200 -150 -100 -50 0 50 100 150 200
INPUT OFFSET VOLTAGE (μV)
0
-500 -400 -300 -200 -100 0 100 200 300 400 500
INPUT OFFSET VOLTAGE DRIFT (nV/°C)
0
-50 -25 0 25 50 75 100 125 150
TEMPERATURE (°C)
10
0
INPUT OFFSET VOLTAGE (μV)
-10
-20
-30
-40
-50
-60
-70
INPUT OFFSET VOLTAGE
vs. INPUT COMMON-MODE VOLTAGE vs. TEMPERATURE
VIN = VDD/2 RLOAD = 10k to VDD/2
TA = -40°C
TA = +25°C
TA = +85°C
toc04
600
INPUT BIAS CURRENT (pA)
400
200
0
INPUT BIAS CURRENT(IB+)
vs. INPUT COMMON MODE VOLTAGE vs. TEMPERATURE
TA = +125°C
TA = +85°C
TA = 25°C
toc05
INPUT BIAS CURRENT (pA)
600
400
200
0
INPUT BIAS CURRENT(IB-)
vs. INPUT COMMON MODE VOLTAGE vs. TEMPERATURE
TA = 125°C
TA = 85°C
TA = +25°C
toc06
-80
-90
TA = +125°C
-1 1 3 5 7 9
INPUT COMMON-MODE VOLTAGE (V)
-200
0 2 4 6 8 10
INPUT COMMON MODE VOLTAGE VCM (V)
-200
0 2 4 6 8 10
INPUT COMMON MODE VOLTAGE VCM (V)
COMMON-MODE REJECTION RATIO (dB)
140
120
100
80
60
40
20
COMMON-MODE REJECTION RATIO vs. TEMPERATURE
toc07
POWER-SUPPLY REJECTION RATIO (dB)
150
130
110
90
70
50
POWER-SUPPLY REJECTION RATIO vs. TEMPERATURE
toc08
0
-50 -25 0 25 50 75 100 125
TEMPERATURE (°C)
30
-50 -25 0 25 50 75 100 125
TEMPERATURE (°C)
(VDD = 10V, VSS = 0V, outputs have RL = 10kΩ to VDD/2. TA = +25°C, unless otherwise specified.)
140
AC COMMON MODE REJECTION RATIO vs. FREQUENCY
toc09
AC POWER SUPPLY REJECTION RATIO (dB)
140
AC PSRR
vs. FREQUENCY
toc10
140
AV = 10V/V
GAIN AND PHASE vs. FREQUENCY (RL= 10kΩ)
toc11
250
120
AC CMRR (dB)
100
80
60
40
20
0
120
100
80
60
40
20
120
100
GAIN (dB)
80
60
40
20
0
-20
PHASE CURVE IS REFERRED TO DEGREE UNITS ON AXIS FAR RIGHT
PHASE GAIN
200
150
100
50
0
-50
-100
-150
-200
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 1E+8 FREQUENCY (Hz)
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 1E+8 FREQUENCY (Hz)
0.01 0.1 1 10 100 1000 10000 100000
FREQUENCY (kHz) Thousands
10
SMALL SIGNAL RESPONSEL (dB)
5
0
-5
-10
-15
-20
SMALL-SIGNAL RESPONSE vs. FREQUENCY
VIN = 100mVP-P | |||||||||||||||||
toc12
10
LARGE SIGNAL RESPONSE (dB)
5
0
-5
-10
-15
-20
LARGE-SIGNAL RESPONSE vs. FREQUENCY
VIN = 2VP-P | |||||||||||||||||||
toc13
INPUT VOLTAGE-NOISE DENSITY vs. FREQUENCY
50
INPUT VOLTAGE-NOISE DENSITY (nV/√Hz)
45
40
35
30
25
20
15
10
5
0
toc14
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 1E+8 FREQUENCY (Hz)
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 1E+8 FREQUENCY (Hz)
10 100 1000 10000 100000
FREQUENCY (Hz)
INPUT VOLTAGE NOISE 0.1Hz TO 10Hz NOISE
INPUT CURRENT-NOISE DENSITY vs. FREQUENCY
2.E-6
2.E-6
1.E-6
5.E-7
VOLTS
0.E+0
-5.E-7
-1.E-6
-2.E-6
-2.E-6
toc15
eN = 21.1621µVP-P
0 4 8 12 16 20 24 28 32
4s/div
2
INPUT CURRENT-NOISE DENSITY (pA/√Hz)
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
toc16
10 100 1000 10000 100000
FREQUENCY (Hz)
(VDD = 10V, VSS = 0V, outputs have RL = 10kΩ to VDD/2. TA = +25°C, unless otherwise specified.)
OUTPUT VOLTAGE HIGH VOH (VDD - VOUT) (mV)
1000
OUTPUT VOTLAGE HIGH
vs. OUTPUT SOURCE CURRENT
toc17
OUTPUT VOLTAGE LOW VOL (VOUT - VSS) (mV)
600
OUTPUT VOTLAGE LOW vs. OUTPUT SINK CURRENT
TA = 125°C
toc18
SMALL-SIGNAL RESPONSE vs. TIME
toc19
750
500
TA = 85°C TA = 125°C
500
400
300
TA = 85°C
VIN
50mV/div
250
0
TA = -40°C
TA = 25°C
200
100
0
TA = -40°C
TA = 25°C
VOUT
50mV/div
0 4 8 12 16 20
SOURCE CURRENT (mA)
0 4 8 12 16 20
SINK CURRENT (mA)
LARGE-SIGNAL RESPONSE vs. TIME
toc20
VIN
100
80
STABILITY
vs. CAPACITIVE LOAD AND RESISTIVE LOAD
STABLE
toc21
VOUTN VINSIDE
VBACKUP
1V/div
60
RESISTIVE LOAD (k)
UNSTABLE
40
1μs/div
VOUT
1V/div
20
0
10 100 1000 10000
CAPACITIVE LOAD (pF)
100
STABILITY
vs. CAPACITIVE LOAD AND ISOLATION RESISTOR toc22
ISOLATION RESISTANCE RISO ()
10
UNSTABLE
1
0.1
STABLE
0.01
100 1000 10000 100000
CAPACITIVE LOAD (pF)
(VDD = 10V, VSS = 0V, outputs have RL = 10kΩ to VDD/2. TA = +25°C, unless otherwise specified.)
2VP-P INPUT
TOTAL HARMONIC DISTORTION+NOISE vs. FREQUENCY
TOTAL HARMONIC DISTORTION+NOISE vs. INPUT FREQUENCY
TOTAL HARMONIC DISTORTION + NOISE (dB)
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
toc24
0
TOTAL HARMONIC DISTORTION + NOISE (dB)
-20
-40
-60
-80
-100
-120
RLOAD
vs. AMPLITUDE
= 10k
1kHz INPUT FREQUENCY
20kHz INPUT FREQUENCY
toc25
10 100 1000 10000 100000
FREQUENCY (Hz)
0 2 4 6 8 10
FREQUENCY (Hz)
CROSSTALK vs. FREQUENCY
0
toc26
100
EMIRR
vs. FREQUENCY
toc27
EMI REJECTION RATIO (dB)
-20 80
CROSSTALK (dB)
-40
60
-60
40
-80
-100 20
-120
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 1E+8 FREQUENCY (Hz)
0
10 100 1000 10000
FREQEUNCY (MHz)
+
1
2
3
4
A
INA-
OUTA
OUTB
INB-
MAX40242
B
INA+
VDD
VSS
INB+
WLP
BUMP (WLP) | NAME | FUNCTION |
A1 | INA- | Channel A Negative Input |
A2 | OUTA | Channel A Output |
A3 | OUTB | Channel B Output |
A4 | INB- | Channel B Negative Input |
B1 | INA+ | Channel A Positive Input |
B2 | VDD | Positive Supply Voltage |
B3 | VSS | Negative Supply Voltage. Connect VSS to ground if single supply is used. |
B4 | INB+ | Channel B Positive Input |
Combining high input impedance, low input bias current, wide bandwidth, and fast settling time, the MAX40242 is an ideal amplifier for driving precision analog-to-digital inputs and buffering digital-to-analog converter outputs.
Input Bias Current
The MAX40242 features a high-impedance CMOS input stage and a special ESD structure that allows low input bias current operation at low-input, common-mode voltages. Low input bias current is useful when interfacing with high-ohmic or capacitive sensors and is beneficial for designing transimpedance amplifiers for photodiode sensors. This makes the device ideal for ground- referenced medical and industrial sensor applications.
Integrated EMI Filter
Electromagnetic interference (EMI) noise occurs at higher frequency that results in malfunction or degradation of electrical equipment.
The MAX40242 has an input EMI filter to avoid the output from getting affected by radio frequency interference. The EMI filter, composed of passive devices, presents significant higher impedance to higher frequencies.
High Supply Voltage Range
The device features 1.2mA current consumption per channel and a voltage supply range from either 2.7V to 20V single supply or ±1.35V to ±10V split supply.
High-Impedance Sensor Application
High impedance sources like pH sensor, photodiodes in applications require negligible input leakage currents to the input transimpedance/buffer structure. The MAX40242 benefits with clean and precise signal conditioning due to its input structure.
The device interfaces to both current-output sensors (photodiodes) (Figure 1), and high-impedance voltage sources (piezoelectric sensors). For current output sensors, a transimpedance amplifier is the most noise- efficient method for converting the input signal to a voltage. High-value feedback resistors are commonly chosen to create large gains, while feedback capaci- tors help stabilize the amplifier by cancelling any poles introduced in the feedback loop by the highly capacitive sensor or cabling. A combination of low-current noise and low-voltage noise is important for these applications. Take care to calibrate out photodiode dark current if DC accuracy is important. The high bandwidth and slew rate also allow AC signal processing in certain medical photodiode sensor applications such as pulse-oximetry. For voltage-output sensors, a noninverting amplifier is typically used to buffer and/or apply a small gain to the
input voltage signal. Due to the extremely high imped- ance of the sensor output, a low input bias current with minimal temperature variation is very important for these applications.
Transimpedance Amplifier
As shown in Figure 1, the noninverting pin is biased at 2V with C2 added to bypass high-frequency noise. This bias voltage to reverse biases the photodiode D1 at 2V which is often enough to minimize the capacitance across the junction. Hence, the reverse current (IR) produced by the photodiode as light photons are incident on it, a proportional voltage is produced at the output of the amplifier by the given relation:
VOUT IR R1
The addition of C1 is to compensate for the instability caused due to the additional capacitance at the input (junction capacitance Cj and input capacitance of the op amp CIN), which results in loss of phase margin. More information about stabilizing the transimpedance amplifier can be found in Application Note 5129: Stabilize Your Transimpedance Amplifier.
R1 100kΩ
+5V
MAX40242
5V
D1
R2 30kΩ
R3 20kΩ
C2 10nF
Figure 1. High-Impedance Source/Sensor Preamp Application
PART | TEMP RANGE | PIN- PACKAGE | TOP MARK |
MAX40242ANA+ | -40ºC to +125ºC | 8-THIN WLP | +AAN |
+Denotes lead(Pb)-free/RoHS-compliant package.
PROCESS: BiCMOS
PACKAGE TYPE | PACKAGE CODE | OUTLINE NO. | LAND PATTERN NO. |
8-THIN WLP | N80D1+1 | 21-100280 | Apps Note 1891 |
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
REVISION NUMBER | REVISION DATE | DESCRIPTION | PAGES CHANGED |
0 | 6/18 | Initial release | — |
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
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