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ISL28274, ISL28474
Data Sheet December 13, 2006 FN6345.0
Micropower, Single Supply, Rail-to-Rail Input-Output Instrumentation Amplifier and Precision Operational Amplifier
The ISL28274 is a combination of a micropower instrumentation amplifier (Amp A) with a low power precision amplifier (Amp B) in a single package. The ISL28474 consist of two micropower instrumentation amplifiers (Amp A) and two low power precision amplifiers (Amp B) in a single package. The amplifiers are optimized for operation at 2.4V to 5V single supplies. Inputs and outputs can operate rail-torail. As with all instrumentation amplifiers, a pair of inputs provide a high common-mode rejection and are completely independent from a pair of feedback terminals. The feedback terminals allow zero input to be translated to any output offset, including ground. A feedback divider controls the overall gain of the amplifier. The additional precision amplifier can be used to generate higher gain, with smaller feedback resistors or used to generate a reference voltage. The instrumentation amp (Amp A) is compensated for a gain of 100 or more and the precision amp (Amp B) is unity gain stable. Both amplifiers have PMOS inputs that provide less than 30pA input bias currents. The amplifiers can be operated from one lithium cell or two Ni-Cd batteries. The amplifiers input range goes from below ground to slightly above positive rail. The output stage swings completely to ground or positive supply - no pull-up or pull-down resistors are needed.
Features
* Combination of IN-AMP and OP-AMP in a single package * 120A supply current for ISL28274 * Input Offset Voltage IN-AMP 400V max * Input Offset Voltage OP-AMP 225V max * 30pA max input bias current * 100dB CMRR and PSRR * Single supply operation of 2.4V to 5.0V * Ground Sensing * Input voltage range is rail-to-rail and output swings rail-to-rail * Pb-free plus anneal available (RoHS compliant)
Applications
* 4-20mA loops * Industrial Process Control * Medical Instrumentations
Ordering Information
PART NUMBER (Note) ISL28274FAZ PART MARKING 28274FAZ QTY. PER PACKAGE TUBE/REEL (Pb-Free) 97/Tube PKG. DWG. #
16 Ld QSOP MDP0040
ISL28274FAZ-T7 28274FAZ Coming Soon ISL28474FAZ ISL28474FAZ
7" 16 Ld QSOP MDP0040 (1000 pcs) Tape & Reel 55 /Tube 24 Ld QSOP MDP0040
Coming Soon ISL28474FAZ 7" 24 Ld QSOP MDP0040 ISL28474FAZ-T7 (1000 pcs) Tape & Reel NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright (c) Intersil Americas Inc. 2006. All Rights Reserved. All other trademarks mentioned are the property of their respective owners.
ISL28274, ISL28474 Pinout
ISL28274 (16 LD QSOP) TOP VIEW
NC 1 IA OUT 2 IA FB+ 3 -+ +IA FB- 4 IA IN- 5 IA IN+ 6 IA EN 7 V- 8 A B 16 V+ 15 OUT 14 NC 13 NC 12 IN11 IN+ 10 EN 9 NC IA OUT_1 1 IA FB+_1 2 -+ +IA FB-_1 3 IA IN-_1 4 IA IN+_1 5 IA EN_1 6 V+ 7 EN_1 8 IN+_1 9 IN-_1 10 NC 11 OUT_1 12 B -+ +B A A
ISL28474 (16 LD QSOP) TOP VIEW
24 IA OUT_2 23 IA FB+_2 22 IA FB-_2 21 IA IN-_2 20 IA IN+_2 19 IA EN_2 18 V17 EN_2 16 IN+_2 15 IN-_2 14 NC 13 OUT_2
IA = Instrumentation Amplifier ++B A = Instrumentation Amplifier = Precision Amplifier
IA = Instrumentation Amplifier +A = Instrumentation Amplifier = Precision Amplifier
2
+-
B
FN6345.0 December 13, 2006
ISL28274, ISL28474
Absolute Maximum Ratings (TA = +25C)
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5V Supply Turn On Voltage Slew Rate . . . . . . . . . . . . . . . . . . . . . 1V/s Input Current (IN, FB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mA Differential Input Voltage (IN, FB) . . . . . . . . . . . . . . . . . . . . . . . 0.5V Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . V- - 0.5V to V+ + 0.5V ESD tolerance, Human Body Model . . . . . . . . . . . . . . . . . . . . . .3kV ESD tolerance, Machine Model . . . . . . . . . . . . . . . . . . . . . . . . .300V
Thermal Information
Thermal Resistance JA (C/W) 16 Ld QSOP Package . . . . . . . . . . . . . . . . . . . . . . . 112 24 Ld QSOP Package . . . . . . . . . . . . . . . . . . . . . . . 88 Output Short-Circuit Duration . . . . . . . . . . . . . . . . . . . . . . .Indefinite Ambient Operating Temperature Range . . . . . . . . .-40C to +125C Storage Temperature Range . . . . . . . . . . . . . . . . . .-65C to +150C Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . +125C
CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA
Electrical Specifications
INSTRUMENTATION AMPLIFIER "A" V+ = +5V, VS- = GND, VCM = 1/2VS+ TA = +25C, unless otherwise specified. For ISL28274 ONLY. Boldface limits apply over the operating temperature range, -40C to +125C. CONDITIONS MIN 400 -750 Temperature = -40C to +125C (see Figure 44 for extended temperature range) -40C to +85C -30 -80 -30 -80 TYP 35 0.7
5
PARAMETER VOS TCVOS IOS IB
DESCRIPTION Input Offset Voltage Input Offset Voltage Temperature Coefficient Input Offset Current between IN+ and IN-, and between FB+ and FB-
MAX 400 750
UNIT V V/C
30 80 30 80
pA pA
Input Bias Current (IN+, IN-, FB+, and (see Figure 36 and 37 for extended temperature FB- terminals) range) -40C to +85C Input Noise Voltage Input Noise Voltage Density f = 0.1Hz to 10Hz fo = 1kHz fo = 1kHz
10
eN
0.75 210 0.65 1
VP-P nV/Hz pA/Hz G V+ V dB dB % 0.65 0.70 V/s MHz
iN RIN VIN CMRR PSRR EG SR GBWP
Input Noise Current Density Input Resistance Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Gain Error Slew Rate Gain Bandwidth Product
V+ = 2.4V to 5.0V VCM = 0V to 5V V+ = 2.4V to 5V RL = 100k to 2.5V RL = 1k to GND
0 80 75 80 75 100 100 -0.2 0.40 0.35 0.5 2.5
Electrical Specifications
OPERATIONAL AMPLIFIER "B" VS+ = +5V, VS- = GND, VCM = 1/2VS+ TA = +25C, unless otherwise specified. For ISL28274 ONLY. Boldface limits apply over the operating temperature range, -40C to +125C. CONDITIONS MIN -225 -450 TYP
20
PARAMETER VOS V OS -----------------Time V OS --------------T IOS
DESCRIPTION Input Offset Voltage Long Term Input Offset Voltage Stability Input Offset Drift vs Temperature Input Offset Current
MAX 225 450
UNIT V V/Mo V/C
1.2 2.2 (see Figure 46 for extended temperature range) -40C to +85C -30 -80
5
30 80
pA
3
FN6345.0 December 13, 2006
ISL28274, ISL28474
Electrical Specifications
OPERATIONAL AMPLIFIER "B" VS+ = +5V, VS- = GND, VCM = 1/2VS+ TA = +25C, unless otherwise specified. For ISL28274 ONLY. Boldface limits apply over the operating temperature range, -40C to +125C. (Continued) CONDITIONS (see Figure 40 and 41for extended temperature range) -40C to +85C f = 0.1Hz to 10Hz fO = 1kHz fO = 1kHz Guaranteed by CMRR test VCM = 0V to 5V V+ = 2.4V to 5V VO = 0.5V to 4.5V, RL = 100k 0 80 75 85 80 200 190 0.12 0.09 100 105 300
0.14
PARAMETER IB
DESCRIPTION Input Bias Current
MIN -30 -80
TYP
10
MAX 30 80
UNIT pA
eN
Input Noise Voltage Peak-to-Peak Input Noise Voltage Density
5.4 50 0.14 5
VPP nV/Hz pA/Hz V dB dB V/mV 0.16 0.21 V/s kHz
iN CMIR CMRR PSRR AVOL SR GBW
Input Noise Current Density Input Voltage Range Common-Mode Rejection Ratio Power Supply Rejection Ratio Large Signal Voltage Gain Slew Rate Gain Bandwidth Product
300
Electrical Specifications
COMMON ELECTRICAL SPECIFICATIONS V+ = 5V, V- = GND, VCM = 1/2VS+ TA = 25C, unless otherwise specified.For ISL28274 ONLY. Boldface limits apply over the operating temperature range, -40C to +125C. CONDITIONS Output low, RL = 100k Output low, RL = 1k Output high, RL = 100k Output high, RL = 1k 4.990 4.97 4.800 4.750 MIN TYP 3 130 4.996 4.880 120 240 4 8 28 25 24 20 2.4 2 0.8 VEN = 5V VEN = 0V 0.8 0 26 1 1.3 50 100 31 26 7 9 156 175 MAX 6 30 175 225 UNIT mV mV V V A A A A mA mA V V V A A
PARAMETER VOUT
DESCRIPTION Maximum Output Voltage Swing
IS,ON
Supply Current, Enabled
ISL28274 All channels enabled ISL28474 All channels enabled
IS,OFF
Supply Current, Disabled
ISL28274 All channels enabled ISL28474 All channels enabled
ISC+ ISCVS VINH VINL IENH IENL
Short Circuit Sourcing Capability Short Circuit Sinking Capability Minimum Supply Voltage Enable Pin High Level Enable Pin Low Level Enable Pin Input Current Enable Pin Input Current
RL = 10 RL = 10
4
FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves
90 GAIN = 10,000 80 GAIN = 5,000 GAIN (dB) 70 60 50 40 30 1 10 100 1k 10k FREQUENCY (Hz) 100k 1M GAIN (dB) GAIN = 2,000 GAIN = 1,000 GAIN = 500 GAIN = 200 GAIN = 100 40 30 1 10 100 1k 10k FREQUENCY (Hz) 100k 1M 80 GAIN = 5,000 70 60 50 GAIN = 2,000 GAIN = 1,000 GAIN = 500 GAIN = 200 GAIN = 100 COMMON-MODE INPUT = V+ 90 GAIN = 10,000 COMMON-MODE INPUT = 1/2V+
FIGURE 1. AMPLIFIER "A"(INAMP) FREQUENCY RESPONSE vs CLOSED LOOP GAIN
FIGURE 2. AMPLIFIER "A"(INAMP) FREQUENCY RESPONSE vs CLOSED LOOP GAIN. VCM = 1/2V+
90 80
45
COMMON-MODE INPUT = VM +10mV GAIN = 10,000
GAIN = 5,000
40 35 30 GAIN (dB)
VS = 5V
GAIN (dB)
70 60 50 40 30 1
GAIN = 2,000 GAIN = 1,000 GAIN = 500 GAIN = 200 GAIN = 100
25 20 15 10 5 0 AV = 100 RL = 10k CL = 10pF RF/RG = 100 RF = 10k RG = 100 10 100 1k 10k
VS = 2.4V
10
100 1k 10k FREQUENCY (Hz)
100k
1M
100k
1M
FREQUENCY (Hz)
FIGURE 3. AMPLIFIER "A"(INAMP) FREQUENCY RESPONSE vs CLOSED LOOP GAIN
FIGURE 4. AMPLIFIER "A"(INAMP) FREQUENCY RESPONSE vs SUPPLY VOLTAGE
50
120 100 2200pF CMRR (dB) 1200pF 80 60 AV = 100 40 56pF 20 0 10
45
GAIN (dB)
40 820pF AV = 100 R = 10k CL = 10pF RF/RG = 100 RF = 10k RG = 100 10 100 1k 10k 100k FREQUENCY (Hz)
35
30
25
1M
100
1k
10k
100k
1M
FREQUENCY (Hz)
FIGURE 5. AMPLIFIER "A"(INAMP) FREQUENCY RESPONSE vs CLOAD
FIGURE 6. AMPLIFIER "A"(INAMP) CMRR vs FREQUENCY
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FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
120 INPUT VOLTAGE NOISE (nV/Hz) 100 80 PSRR (dB) PSRR+ 60 40 AV = 100 20 0 10 100 1k 10k 100k 1M FREQUENCY (Hz) PSRR700 600 500 400 300 200 100 0 1 10 100 1k 10k 100k FREQUENCY (Hz) AV = 100
FIGURE 7. AMPLIFIER "A"(INAMP) PSRR vs FREQUENCY
FIGURE 8. AMPLIFIER "A"(INAMP) INPUT VOLTAGE NOISE SPECTRAL DENSITY
2.0 1.8 CURRENT NOISE (pA/Hz) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 1 10 100 1k 10k 100k TIME (1s/DIV) AV = 100 VOLTAGE NOISE (2V/DIV)
FREQUENCY (Hz)
FIGURE 9. AMPLIFIER "A"(INAMP) INPUT CURRENT NOISE SPECTRAL DENSITY
FIGURE 10. AMPLIFIER "A"(INAMP) 0.1 Hz TO 10Hz INPUT VOLTAGE NOISE
+1 0 -1 -2 GAIN (dB) -3 -4 -5 V OUT = 50mVp-p AV = 1 -6 CL = 3pF -7 RF=0/RG = INF 8 1k 10k 100k FREQUENCY (Hz) 1M 5M VS = 2.5V RL = 10k VS = 2.5V RL = 1k VS = 1.2V RL = 1k GAIN (dB) VS = 1.2V RL = 10k
45 40 35 30 25 20 15 10 5 0 100 1k 10k FREQUENCY (Hz) 100k 1M AV = 100 RL = 10k CL = 3pF RF = 100k RG = 1k VS = 2.5V VS = 1.2V
VS = 1.0V
FIGURE 11. AMPLIFIER "B" (OP-AMP) FREQUENCY RESPONSE vs SUPPLY VOLTAGE
FIGURE 12. AMPLIFIER "B" (OP-AMP) FREQUENCY RESPONSE vs SUPPLY VOLTAGE
6
FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
100 INPUT OFFSET VOLTAGE (V) VCM = VDD/2 INPUT OFFSET VOLTAGE (V) 80 60 40 20 0 -20 -40 -60 -80 -100 0 1 2 3 OUTPUT VOLTAGE (V) 4 5 VDD = 2.5V VDD = 5V 0
-20
VOS, V
-40
-60
-80
-100 0 1 2 3 4 5 COMMON-MODE INPUT VOLTAGE (V)
FIGURE 13. AMPLIFIER "B" (OP-AMP) INPUT OFFSET VOLTAGE vs OUTPUT VOLTAGE
FIGURE 14. AMPLIFIER "B" (OP-AMP) INPUT OFFSET VOLTAGE vs COMMON-MODE INPUT VOLTAGE
120
80
100 80 PHASE () PHASE GAIN (dB) 60 40
200 150 100 50 0 PHASE () 1M
80 GAIN (dB)
40
40
0
0
-40
20 0 -20 10
GAIN
-50 -100 -150 1M
-40
-80
-80 1 10 100 1k 10k 100k 1M FREQUENCY (Hz)
-120 10M
100
1k
10k
100k
FREQUENCY (Hz)
FIGURE 15. AMPLIFIER "B" (OP-AMP) AVOL vs FREQUENCY @ 100k LOAD
FIGURE 16. AMPLIFIER "B" (OP-AMP) AVOL vs FREQUENCY @ 1k LOAD
10 0 -10 -20 -30 -40 PSRR (dB) -50 -60 -70 -80 -90 -100 10 100 1k 10k 100k 1M TEMPERATURE (C) PSRR + PSRR VS = 5VDC VSOURCE = 1Vp-p RL = 10k AV = +1 CMRR (dB)
10 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 10 100 1k 10k 100k VS = 2.5VDC VSOURCE = 1Vp-p RL = 10k
TEMPERATURE (C)
FIGURE 17. AMPLIFIER "B" (OP-AMP) PSRR vs FREQUENCY
FIGURE 18. AMPLIFIER "B" (OP-AMP) CMRR vs FREQUENCY
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FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
2.56 2.54 2.52 VOLTS (V) 2.50 2.48 2.46 2.44 2.42 0 2 4 6 8 10 12 TIME (s) 14 16 18 20 0 50 100 150 TIME (s) 200 250 VS = 5VDC VOUT = 0.1Vp-p RL = 1k AV = +1 0 VOUT VOLTS (V) 3.0 2.0 1.0 VIN VIN 4.0 5.0 VS = 5VDC VOUT = 2Vp-p RL = 1k AV = -2 VOUT
FIGURE 19. AMPLIFIER "B" (OP-AMP) SMALL SIGNAL TRANSIENT RESPONSE
FIGURE 20. AMPLIFIER "B" (OP-AMP) LARGE SIGNAL TRANSIENT RESPONSE
10.00
1k VOLTAGE NOISE (nV/Hz)
CURRENT NOISE (pA/Hz)
1.00
100
0.10
10
0.01 1 10 100 1k 10k 100k FREQUENCY (Hz)
1 1 10 100 1k 10k 100k FREQUENCY (Hz)
FIGURE 21. AMPLIFIER "B" (OP-AMP) CURRENT NOISE vs FREQUENCY
FIGURE 22. AMPLIFIER "B" (OP-AMP) VOLTAGE NOISE vs FREQUENCY
6 VIN 5 VOLTAGE NOISE (1V/DIV) 4
100K
VS +
V+ = 5V
VOLTS (V)
3 2 1
100K
DUT +
VS -
1K
Function Generator 33140A
VOUT
5.4VP-P
0 0 TIME (1s/DIV) 50 100 TIME (ms) 150 200
FIGURE 23. AMPLIFIER "B" (OP-AMP) 0.1Hz TO 10Hz INPUT VOLTAGE NOISE
FIGURE 24. AMPLIFIER "B" (OP-AMP) INPUT VOLTAGE SWING ABOVE THE V+ SUPPLY
8
FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
155 135 115 95 75 55 35 2 2.5 3 3.5 4 4.5 5 5.5 SUPPLY VOLTAGE (V) 0.1V/DIV 0 VOUT 1V/DIV EN INPUT AV = -1 VIN = 200mVp-p V+ = 5V V- = 0V
SUPPLY CURRENT (A)
0 10s/DIV
FIGURE 25. SUPPLY CURRENT vs SUPPLY VOLTAGE
FIGURE 26. AMPLIFIER "B" (OP-AMP) ENABLE TO OUTPUT DELAY TIME
170 160 150 CURRENT (A) 140 130 120 110 100 90
n = 100
5.0 MAX 4.8 4.6 MEDIAN CURRENT (A) 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 -40 MIN -20 0 20 40 60 80 100 120 MEDIAN n = 100 MAX
MIN
80 -40
-20
0
20
40
60
80
100
120
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 27. TOTAL SUPPLY CURRENT vs TEMPERATURE VS = 2.5V ENABLED. RL = INF
FIGURE 28. DISABLED POSITIVE SUPPLY CURRENT vs TEMPERATURE VS = 2.5V. RL = INF
-4.0 n = 100 MAX -4.5 IA FB+ IBIAS (pA) CURRENT (A) -5.0 -5.5 -6.0 -6.5 -40 MEDIAN
50 MIN 0 -50 -100 -150 -200 -250 40 60 80 100 120 -300 -40 -20 0 20 40 60 80 MEDIAN MAX n = 100
MIN
-20
0
20
100
120
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 29. DISABLED NEGATIVE SUPPLY CURRENT vs TEMPERATURE VS = 2.5V. RL = INF
FIGURE 30. I BIAS (IA FB+) vs TEMPERATURE VS = 2.5V.
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FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
40 20 0 IA FB- IBIAS (pA) -20 -40 -60 -80 -100 -120 -140 -160 -40 -20 0 20 40 60 80 MEDIAN MAX IA FB+ IBIAS (pA) MIN n = 100 -25 -75 -125 -175 -225 -275 -40 MEDIAN MAX -20 0 20 40 60 80 100 120 MIN 25 n = 100
100
120
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 31. I BIAS (IA FB-) vs TEMPERATURE VS = 2.5V.
FIGURE 32. I BIAS (IA FB+) vs TEMPERATURE VS = 1.2V
50 n = 100 0 IA FB- IBIAS (pA) -50 -100 -150 MAX -200 -250 -40 MIN IA IN+ IBIAS (pA)
50 0 -50 -100 -150 -200 -250 -300 -20 0 20 40 60 80 100 120 -350 -40 -20 0 20 40 60 80 MAX MEDIAN MIN n = 100
MEDIAN
100
120
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 33. I BIAS (IA FB-) vs TEMPERATURE VS = 1.2V
FIGURE 34. I BIAS (IA IN+) vs TEMPERATURE VS = 2.5V
50 n = 100 0 MIN IA IN+ IBIAS (pA) IA IN- IBIAS (pA) -50 -100 -150 MEDIAN -200 -250 -300 -40 -20 0 20 40 60 80 MAX
50 n = 100 0 -50 -100 -150 MEDIAN -200 -250 120 -300 -40 -20 0 20 40 60 80 MAX MIN
100
100
120
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 35. I BIAS (IA IN-) vs TEMPERATURE VS = 2.5V
FIGURE 36. I BIAS (IA IN+) vs TEMPERATURE VS = 1.2V
10
FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
50 n = 100 0 IA IN- IBIAS (pA) IN+ IBIAS (pA) -50 -100 -150 -200 -250 -40 MEDIAN MAX 0 -50 -100 -150 -200 -250 -40 MEDIAN MAX 50 n = 100
MIN
MIN
OU
-20
0
20
40
60
80
100
120
-20
0
TEMPERATURE (C)
20 40 60 80 TEMPERATURE (C)
100
120
FIGURE 37. I BIAS (IA IN-) vs TEMPERATURE VS = 1.2V
FIGURE 38. I BIAS(IN+) vs TEMPERATURE VS = 2.5V
30 10 -10 IN+ IBIAS (pA) IN- IBIAS (pA) -30 -50 -70 -90 -110 -130 -150 -40 -20 0 20 40 60 80 100 120 MEDIAN MAX MIN n = 100
40 n = 100 -10 -60 -110 -160 -210 -260 -310 -40 -20 0 20 40 60 MAX MEDIAN MIN
80
100
120
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 39. I BIAS(IN-) vs TEMPERATURE VS = 2.5V
FIGURE 40. I BIAS(IN+) vs TEMPERATURE VS = 1.2V
40 n = 100 -10 -60 IN- IBIAS (pA) -110 -160 -210 -260 -310 -40 -20 0 20 40 60 80 TEMPERATURE (C) 100 120 MIN MEDIAN MAX IA IOS (pA)
40.0 MAX 20.0 0.0 -20.0 -40.0 -60.0 -80.0 -100.0 -120.0 -140.0 -40 -20 0 20 40 60 80 TEMPERATURE (C) 100 120 MEDIAN MIN n = 100
FIGURE 41. I BIAS(IN-) vs TEMPERATURE VS = 1.2V
FIGURE 42. IA INPUT OFFSET CURRENT vs TEMPERATURE VS = 2.5V
11
FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
50 40 30 IA IOS (pA) 20 MAX IOS (pA) 10 0 -10 -20 -30 -40 -50 -40 -20 0 20 40 60 80 MEDIAN MIN 100 120 -200 -40 -20 0 20 40 60 80 TEMPERATURE (C) 100 120 n = 100 50 0 -50 -100 -150 MEDIAN MIN MAX 100 n = 100
TEMPERATURE (C)
FIGURE 43. IA INPUT OFFSET CURRENT vs TEMPERATURE VS = 1.2V
FIGURE 44. INPUT OFFSET CURRENT vs TEMPERATURE VS = 2.5V
40 MAX 20 0 IA VOS (V) -20 IOS (pA) -40 -60 -80 -100 -120 -1400 -40 -20 0 20 40 60 80 MEDIAN MIN 100 120 n = 100
800 600 400 200 0 -200 -400 -600 -800 -40 -20 0 MAX 20 40 60 80 TEMPERATURE (C) MEDIAN
n = 100 MIN
100
120
TEMPERATURE (C)
FIGURE 45. INPUT OFFSET CURRENT vs TEMPERATURE VS = 1.2V
800 600 400 IA VOS (V) MIN
FIGURE 46. IA INPUT OFFSET VOLTAGE vs TEMPERATURE VS = 2.5V
500 400 300 200 VOS (V) 100 0 -100 -200 -300 MEDIAN
n = 100
n = 100 MIN
200 0 -200 -400 -600 -800 -40 -20 0 MAX 20 40 60 80 TEMPERATURE (C) 100 120 MEDIAN
-400 -500 -40 -20 0
MAX 20 40 60 80 TEMPERATURE (C) 100 120
FIGURE 47. IA INPUT OFFSET VOLTAGE vs TEMPERATURE VS = 1.2V
FIGURE 48. INPUT OFFSET VOLTAGE vs TEMPERATURE VS = 2.5V
12
FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
500 400 300 200 VOS (V) 100 0 -100 -200 -300 -400 -500 -40 -20 0 MAX 20 40 60 80 TEMPERATURE (C) 100 120 MEDIAN n = 100 MIN IA CMRR (dB) 145 n = 100 135 125 115 MEDIAN 105 95 85 75 -40 MAX -20 0 20 40 60 80 100 120 TEMPERATURE (C) MIN
FIGURE 49. INPUT OFFSET VOLTAGE vs TEMPERATURE VS = 1.2V
FIGURE 50. IA CMRR vs TEMPERATURE VCM = +2.5V TO -2.5V
140 n = 100 130 120 110 100 90 80 -40 MAX MIN
155 n = 100 145 135 MIN
CMRR (dB)
IA PSRR (dB)
125 115 105 95 85 MAX MEDIAN
MEDIAN
-20
0
20
40
60
80
100
120
75 -40
-20
0
20
40
60
80
100
120
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 51. CMRR vs TEMPERATURE VCM = +2.5V TO -2.5V
FIGURE 52. IA PSRR vs TEMPERATURE VS = 2.5V
4.910 155 145 135 PSRR (dB) 125 115 105 95 85 75 -40 -20 0 20 40 60 80 TEMPERATURE (C) 100 120 MAX MEDIAN MIN IA VOUT (V) n = 100 4.900 MIN 4.890 4.880 4.870 4.860 4.850 4.840 -40 -20 0 20 40 60 80 100 120 MEDIAN MAX n = 100
TEMPERATURE (C)
FIGURE 53. PSRR vs TEMPERATURE VS = 2.5V
FIGURE 54. IA VOUT HIGH vs TEMPERATURE RL = 1k. VS = 2.5V
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FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
4.9980 n = 100 4.9975 MIN IA VOUT (mV) IA VOUT (V) 4.9970 4.9965 4.9960 4.9955 4.9950 -40 MEDIAN MAX 160 150 140 130 120 110 100 -20 0 20 40 60 80 TEMPERATURE (C) 100 120 90 -40 -20 0 MAX MEDIAN MIN 170 n = 100
20 40 60 80 TEMPERATURE (C)
100
120
FIGURE 55. IA VOUT HIGH vs TEMPERATURE RL = 100k. VS = 2.5V
FIGURE 56. IA VOUT LOW vs TEMPERATURE RL = 1k. VS = 2.5V
6.5 n = 100 6.0 IA VOUT (mV) 5.5 5.0 4.5 4.0 3.5 -40 MAX MIN VOUT (V)
4.910 n = 100 4.900 MIN 4.890 4.880 4.870 4.860 4.850 -40 MEDIAN
MEDIAN
MAX
-20
0
20 40 60 80 TEMPERATURE (C)
100
120
-20
0
20
40
60
80
100
120
TEMPERATURE (C)
FIGURE 57. IA VOUT LOW vs TEMPERATURE RL = 100k. VS = 2.5V
FIGURE 58. VOUT HIGH vs TEMPERATURE RL = 1k. VS = 2.5V
4.9986 4.9984 4.9982 4.9980 VOUT (V) 4.9978 4.9976 4.9974 4.9972 4.9970 4.9968 4.9966 -40 -20 0 20 40 60 80 TEMPERATURE (C) 100 120 MAX MEDIAN VOUT (mV) MIN n = 100
170 n = 100 160 150 140 130 120 110 100 90 -40 -20 0 20 40 60 80 100 120 MAX MEDIAN MIN
TEMPERATURE (C)
FIGURE 59. VOUT HIGH vs TEMPERATURE RL = 100k. VS = 2.5V
FIGURE 60. VOUT LOW vs TEMPERATURE RL = 1k. VS = 2.5V
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FN6345.0 December 13, 2006
ISL28274, ISL28474 Typical Performance Curves (Continued)
4.4 4.2 MIN 4.0 VOUT (mV) 3.8 3.6 3.4 3.2 3.0 -40 -20 0 20 MAX MEDIAN n = 100
40
60
80
100
120
TEMPERATURE (C)
FIGURE 61. VOUT LOW vs TEMPERATURE RL = 100k. VS = 2.5V
Pin Descriptions
ISL28274 ISL28474 (16 LD QSOP) (24 LD QSOP) 1, 9, 13, 14 11, 14 2 1, 24 3 2, 23 4 3, 22 5 4, 21 6 5, 20 7 6, 19 8 10 8, 17 11 9, 16 12 10, 15 15 12, 13 16 7 18 IA OUT IA OUT_1/2 IA FB+ IA FB+_1/2 IA FBIA FB-_1/2 IA INIA IN-_1/2 IA IN+ IA IN+_1/2 IA EN IA EN_1/2 VEN EN 1/2 IN+ IN+ 1/2 ININ- 1/2 OUT OUT 1/2 V+ Circuit 3 Circuit 1 Circuit 1 Circuit 1 Circuit 1 Circuit 2 Circuit 4 Circuit 2 Circuit 1 Circuit 1 Circuit 3 Circuit 4 Instrumentation Amplifier output Instrumentation Amplifier Feedback from non-inverting output Instrumentation Amplifier Feedback from inverting output Instrumentation Amplifier inverting input Instrumentation Amplifier non-inverting input Instrumentation Amplifier enable pin internal pull-down; Logic "1" selects the disabled state; Logic "0" selects the enabled state. Negative power supply Amplifier enable pin with internal pull-down; Logic "1" selects the disabled state; Logic "0" selects the enabled state. Amplifier non-inverting input Amplifier inverting input Amplifier output Positive power supply PIN NAME NC EQUIVALENT CIRCUIT No internal connection DESCRIPTION
IA = Instrumentation Amplifier
V+ INLOGIC PIN VCIRCUIT 2 CIRCUIT 3 V+ V+ OUT VVCIRCUIT 4 V+
CAPACITIVELY COUPLED ESD CLAMP
IN+ V-
CIRCUIT 1
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FN6345.0 December 13, 2006
ISL28274, ISL28474 Description of Operation and Application Information
Product Description
The ISL28274 and ISL28474 provide both a micropower instrumentation amplifier (Amp A) and a low power precision amplifier (Amp B) in the same package. The amplifiers deliver rail-to-rail input amplification and rail-to-rail output swing on a single 2.4V to 5V supply. They also deliver excellent DC and AC specifications while consuming only 60A typical supply current per amplifier. Because the instrumentation amplifiers provide an independent pair of feedback terminals to set the gain and to adjust the output level, the in-amp achieve high common-mode rejection ratio regardless of the tolerance of the gain setting resistors. The instrumentation amplifier is internally compensated for a minimum closed loop gain of 100 or greater. An EN pin is used to reduce power consumption, typically 4A for the ISL28274 and 8A for the ISL28474, while both amplifiers are disabled. The user has independent control of each amplifier via separate EN pins. of the ISL28274 in-amp is to maintain the differential voltage across FB+ and FB- equal to IN+ and IN-; (FB+ - FB-) = (IN+ - IN-). Consequently, the transfer function can be derived. The gain is set by two external resistors, the feedback resistor RF, and the gain resistor RG.
2.4V to 5V 16 VIN/2 6 IN+ 5 INVIN/2 3 FB+ VCM 4 FB+ ISL28274 + 8 VS7 VS+ EN 2 EN_BAR
Amp "A"
VOUT
RG
RF
FIGURE 62. GAIN IS BY EXTERNAL RESISTORS RF AND RG
Input Protection
The input and feedback terminals have internal ESD protection diodes to both positive and negative supply rails, limiting the input voltage to within one diode drop beyond the supply rails. If overdriving the inputs is necessary, the external input current must never exceed 5mA. External series resistor may be used as a protection to limit excessive external voltage and current from damaging the inputs.
RF VOUT = 1 + ------- VIN R G
In Figure 62, the FB+ pin and one end of resistor RG are connected to GND. With this configuration, the above gain equation is only true for a positive swing in VIN; negative input swings will be ignored and the output will be at ground.
Reference Connection
Unlike a three-opamp instrumentation amplifier, a finite series resistance seen at the REF terminal does not degrade the high CMRR performance eliminating the need for an additional external buffer amplifier. Figure 63 uses the FB+ pin to provide a high impedance REF terminal.
2.4V to 5V 16 VIN/2 6 IN+ 5 INVIN/2 3 FB+ VCM 2.9V to 5V R1 REF R2 RG RF 4 FB+ ISL28274 + 8 VS7 VS+ EN 2 EN_BAR
Input Stage and Input Voltage Range
The input terminals (IN+ and IN-) of both amplifiers "A" and amp "B" are single differential pair P-MOSFET devices aided by an Input Range Enhancement Circuit to increase the headroom of operation of the common-mode input voltage. The feedback terminals (FB+ and FB-) of amplifier "A" also have a similar topology. As a result, the input common-mode voltage range is rail-to-rail. These amps are able to handle input voltages that are at or slightly beyond the supply and ground making them well suited for single 5V or 3.3V low voltage supply systems. There is no need then to move the common-mode input to achieve symmetrical input voltage.
Amp "A"
VOUT
Output Stage and Output Voltage Range
A pair of complementary MOSFET devices drives the output VOUT to within a few mV of the supply rails. At a 100k load, the PMOS sources current and pulls the output up to 4mV below the positive supply, while the NMOS sinks current and pulls the output down to 3mV above the negative supply, or ground in the case of a single supply operation. The current sinking and sourcing capability of the ISL28274 are internally limited to 31mA.
FIGURE 63. GAIN SETTING AND REFERENCE CONNECTION RF RF VOUT = 1 + ------- ( VIN ) + 1 + ------- ( VREF ) R G R G
Gain Setting of Instrumentation amp "A"
VIN, the potential difference across IN+ and IN-, is replicated (less the input offset voltage) across FB+ and FB-. The goal 16
FN6345.0 December 13, 2006
ISL28274, ISL28474
The FB+ pin is used as a REF terminal to center or to adjust the output. Because the FB+ pin is a high impedance input, an economical resistor divider can be used to set the voltage at the REF terminal without degrading or affecting the CMRR performance. Any voltage applied to the REF terminal will shift VOUT by VREF times the closed loop gain, which is set by resistors RF and RG as shown in Figure 63. The FB+ pin can also be connected to the other end of resistor, RG. See Figure 64. Keeping the basic concept that the in-amps maintain constant differential voltage across the input terminals and feedback terminals (IN+ - IN- = FB+ - FB-), the transfer function of Figure 64 can be derived.
2.4V to 5V 16 VIN/2 6 IN+ 5 INVIN/2 3 FB+ VCM 4 FB+ ISL28274 + 8 7 VS+ EN 2 EN_BAR
amplifiers will power down when EN bar is pulled above 2V, and will power on when EN bar is pulled below 0.8V.
Using Only the Instrumentation Amplifier
If the application only requires the instrumentation amp, the user must configure the unused Opamp to prevent it from oscillating. The unused Opamp will oscillate if the input and output pins are floating. This will result in higher than expected supply currents and possible noise injection into the in-amp. The proper way to prevent this oscillation is to short the output to the negative input and ground the positive input (as shown in Figure 65).
+
Amp "A"
VOUT
FIGURE 65. PREVENTING OSCILLATIONS IN UNUSED CHANNELS
Proper Layout Maximizes Performance
VS-
RG VREF
RF
FIGURE 64. REFERENCE CONNECTION WITH AN AVAILABLE VREF RF VOUT = 1 + ------- ( VIN ) + ( VREF ) R G
A finite resistance Rs in series with the VREF source, adds an output offset of VIN*(RS/RG). As the series resistance Rs approaches zero, the gain equation is simplified to the above equation for Figure 64. VOUT is simply shifted by an amount VREF.
To achieve the maximum performance of the high input impedance and low offset voltage, care should be taken in the circuit board layout. The PC board surface must remain clean and free of moisture to avoid leakage currents between adjacent traces. Surface coating of the circuit board will reduce surface moisture and provide a humidity barrier, reducing parasitic resistance on the board. When input leakage current is a concern, the use of guard rings around the amplifier inputs will further reduce leakage currents. Figure 66 shows a guard ring example for a unity gain amplifier that uses the low impedance amplifier output at the same voltage as the high impedance input to eliminate surface leakage. The guard ring does not need to be a specific width, but it should form a continuous loop around both inputs. For further reduction of leakage currents, components can be mounted to the PC board using Teflon standoff insulators.
HIGH IMPEDANCE INPUT IN V+ 1/2 ISL28274 1/4 ISL28474
External Resistor Mismatches
Because of the independent pair of feedback terminals provided by the ISL28274, the CMRR is not degraded by any resistor mismatches. Hence, unlike a three opamp and especially a two opamp in-amp, the ISL28274 reduce the cost of external components by allowing the use of 1% or more tolerance resistors without sacrificing CMRR performance. The ISL28274 CMRR will be 100dB regardless of the tolerance of the resistors used.
FIGURE 66. GUARD RING EXAMPLE FOR UNITY GAIN AMPLIFIER
Disable/Power-Down
The ISL28274 Amplifiers "A" and "B" can be powered down reducing the supply current to typically 4A. When disabled, the output is in a high impedance state. The active low EN bar pin has an internal pull down and hence can be left floating and the in-amp and Opamp enabled by default. When the EN bar is connected to an external logic, the
Current Limiting
The ISL28274 has no internal current-limiting circuitry. If the output is shorted, it is possible to exceed the Absolute Maximum Rating for output current or power dissipation, potentially resulting in the destruction of the device.
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FN6345.0 December 13, 2006
ISL28274, ISL28474
Power Dissipation
It is possible to exceed the +150C maximum junction temperatures under certain load and power-supply conditions. It is therefore important to calculate the maximum junction temperature (TJMAX) for all applications to determine if power supply voltages, load conditions, or package type need to be modified to remain in the safe operating area. These parameters are related in Equation 1:
T JMAX = T MAX + ( JA xPD MAXTOTAL ) (EQ. 1)
where: * PDMAXTOTAL is the sum of the maximum power dissipation of each amplifier in the package (PDMAX) * PDMAX for each amplifier can be calculated as shown in Equation 2:
V OUTMAX PD MAX = 2*V S x I SMAX + ( V S - V OUTMAX ) x --------------------------RL (EQ. 2)
where: * TMAX = Maximum ambient temperature * JA = Thermal resistance of the package * PDMAX = Maximum power dissipation of 1 amplifier * VS = Supply voltage * IMAX = Maximum supply current of 1 amplifier * VOUTMAX = Maximum output voltage swing of the application * RL = Load resistance
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FN6345.0 December 13, 2006
ISL28274, ISL28474 Quarter Size Outline Plastic Packages Family (QSOP)
A D N (N/2)+1
MDP0040
QUARTER SIZE OUTLINE PLASTIC PACKAGES FAMILY SYMBOL QSOP16 QSOP24 QSOP28 TOLERANCE NOTES A
PIN #1 I.D. MARK
0.068 0.006 0.056 0.010 0.008 0.193 0.236 0.154 0.025 0.025 0.041 16
0.068 0.006 0.056 0.010 0.008 0.341 0.236 0.154 0.025 0.025 0.041 24
0.068 0.006 0.056 0.010 0.008 0.390 0.236 0.154 0.025 0.025 0.041 28
Max. 0.002 0.004 0.002 0.001 0.004 0.008 0.004 Basic 0.009 Basic Reference
1, 3 2, 3 Rev. E 3/01
A1 A2 b c
E
E1
1 B 0.010 CAB
(N/2)
D E E1
e C SEATING PLANE 0.004 C 0.007 CAB b
H
e L L1 N NOTES:
L1 A c SEE DETAIL "X"
1. Plastic or metal protrusions of 0.006" maximum per side are not included. 2. Plastic interlead protrusions of 0.010" maximum per side are not included. 3. Dimensions "D" and "E1" are measured at Datum Plane "H". 4. Dimensioning and tolerancing per ASME Y14.5M-1994.
0.010 A2 GAUGE PLANE L 44 DETAIL X
A1
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation's quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com 19
FN6345.0 December 13, 2006

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