ISL28274, ISL28474
®
Data Sheet
May 14, 2009
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
consists 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-to-rail. 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.
FN6345.3
Features
• Combination of IN-AMP and OP-AMP in a Single Package
• 120µA Supply Current for ISL28274
• Input Offset Voltage IN-AMP 500µV Max
• Input Offset Voltage OP-AMP 225µV 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 available (RoHS Compliant)
Applications
• 4mA to 20mA Loops
• Industrial Process Control
• Medical Instrumentation
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.
Ordering Information
PART NUMBER
(Note)
PART
MARKING
PACKAGE
(Pb-Free)
PKG.
DWG. #
ISL28274FAZ*
28274 FAZ
16 Ld QSOP
MDP0040
ISL28474FAZ*
ISL28474 FAZ
24 Ld QSOP
MDP0040
*Add “-T7” suffix for tape and reel. Please refer to TB347 for details
on reel specifications
NOTE: These Intersil Pb-free plastic packaged products employ
special Pb-free material sets, molding compounds/die attach
materials, and 100% matte tin plate plus anneal (e3 termination
finish, which is 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 © Intersil Americas Inc. 2006, 2007, 2009. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
ISL28274, ISL28474
Pinout
ISL28474
(24 LD QSOP)
TOP VIEW
ISL28274
(16 LD QSOP)
TOP VIEW
16 V+
IA OUT_1 1
24 IA OUT_2
IA OUT 2
15 OUT
IA FB+_1 2
23 IA FB+_2
IA FB+ 3
14 NC
IA FB-_1 3
13 NC
IA IN-_1 4
21 IA IN-_2
IA IN- 5
12 IN-
IA IN+_1 5
20 IA IN+_2
IA IN+ 6
11 IN+
DNC 6
DNC
10 DNC
+ -
- +
7
V- 8
9 NC
IA = INSTRUMENTATION
AMPLIFIER
+ B
= INSTRUMENTATION
AMPLIFIER
= PRECISION AMPLIFIER
V+ 7
18 V-
DNC 8
17 DNC
IN+_1 9
16 IN+_2
IN-_1 10
15 IN-_2
NC 11
B
B
14 NC
13 OUT_2
OUT_1 12
IA = INSTRUMENTATION
AMPLIFIER
A
+ + -
A
22 IA FB-_2
19 DNC
+ -
B
A
- +
A
+ -
IA FB- 4
A
- +
NC 1
B
2
= INSTRUMENTATION
AMPLIFIER
= PRECISION AMPLIFIER
FN6345.3
May 14, 2009
+ -
ISL28274, ISL28474
Absolute Maximum Ratings (TA = +25°C)
Thermal Information
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5V
Supply Turn-On Voltage Slew Rate . . . . . . . . . . . . . . . . . . . . . 1V/µs
Input Current (IN, FB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mA
Differential Input Voltage (IN, FB) . . . . . . . . . . . . . . . . . . . . . . . 0.5V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . V- - 0.5V to V+ + 0.5V
ESD Rating
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3kV
Machine Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300V
Thermal Resistance (Typical Note 1)
θJA (°C/W)
16 Ld QSOP Package . . . . . . . . . . . . . . . . . . . . . . .
112
24 Ld QSOP Package . . . . . . . . . . . . . . . . . . . . . . .
88
Output Short-Circuit Duration . . . . . . . . . . . . . . . . . . . . . . .Indefinite
Ambient Operating Temperature Range . . . . . . . . .-40°C to +125°C
Storage Temperature Range . . . . . . . . . . . . . . . . . .-65°C to +150°C
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . +125°C
Pb-Free Reflow Profile. . . . . . . . . . . . . . . . . . . . . . . . .see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and
result in failures not covered by warranty.
NOTES:
1. θJA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
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
PARAMETER
VOS
TCVOS
IOS
INSTRUMENTATION AMPLIFIER “A” V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise
specified. For ISL28274 ONLY. Boldface limits apply over the operating temperature range, -40°C to +125°C,
temperature data established by characterization.
DESCRIPTION
Input Offset Voltage
MIN
(Note 2)
CONDITIONS
MAX
(Note 2)
UNIT
ISL28274
-400
-750
35
400
750
µV
ISL28474
-500
-750
35
500
750
µV
Input Offset Voltage
Temperature Coefficient
Temperature = -40°C to +125°C
3
Input Offset Current
between IN+ and IN-, and
between FB+ and FB-
(see Figure 43 for extended temperature range)
-40°C to +85°C
IB
Input Bias Current (IN+, IN- (see Figures 35 and 36 for extended temperature range)
FB+, and FB- terminals)
-40°C to +85°C
eN
Input Noise Voltage
iN
TYP
µV/°C
-30
-80
±5
30
80
pA
-30
-80
±10
30
80
pA
f = 0.1Hz to 10Hz
6
µVP-P
Input Noise Voltage Density fo = 1kHz
78
nV/√Hz
Input Noise Current Density fo = 1kHz
0.19
pA/√Hz
1
GΩ
RIN
Input Resistance
VIN
Input Voltage Range
V+ = 2.4V to 5.0V
0
CMRR
Common Mode Rejection
Ratio
VCM = 0V to 5V
80
75
100
dB
PSRR
Power Supply Rejection
Ratio
V+ = 2.4V to 5V
80
75
100
dB
EG
Gain Error
RL = 100kΩ to 2.5V
-0.2
%
SR
Slew Rate
RL = 1kΩ to VCM
GBWP
Gain Bandwidth Product
3
VOUT = 10mVP-P; RL = 10kΩ
V+
V
ISL28274
0.40
0.35
0.5
0.65
0.70
V/µs
ISL28474
0.40
0.35
0.5
0.7
0.75
V/µs
6
MHz
FN6345.3
May 14, 2009
ISL28274, ISL28474
Electrical Specifications
PARAMETER
VOS
OPERATIONAL AMPLIFIER “B” V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified.
For ISL28274 ONLY. Boldface limits apply over the operating temperature range, -40°C to +125°C.
DESCRIPTION
MIN
(Note 2)
CONDITIONS
Input Offset Voltage
-225
-450
TYP
±20
MAX
(Note 2)
225
450
UNIT
µV
ΔV OS
-----------------ΔTime
Long Term Input Offset Voltage
Stability
1.2
µV/Mo
ΔV OS
---------------ΔT
Input Offset Drift vs Temperature
2.2
µV/°C
Input Offset Current
(see Figure 45 for extended temperature range)
-40°C to +85°C
-30
-80
±5
30
80
pA
IB
Input Bias Current
(see Figures 39 and 40 for extended temperature range)
-40°C to +85°C
-30
-80
±10
30
80
pA
eN
Input Noise Voltage Peak-to-Peak f = 0.1Hz to 10Hz
5.4
µVP-P
Input Noise Voltage Density
fO = 1kHz
50
nV/√Hz
Input Noise Current Density
fO = 1kHz
0.14
pA/√Hz
CMIR
Input Voltage Range
Guaranteed by CMRR test
0
CMRR
Common-Mode Rejection Ratio
VCM = 0V to 5V
80
75
100
dB
PSRR
Power Supply Rejection Ratio
V+ = 2.4V to 5V
85
80
105
dB
AVOL
Large Signal Voltage Gain
VO = 0.5V to 4.5V, RL = 100kΩ
200
190
300
V/mV
Slew Rate
RL = 1kΩ to VCM
0.12
0.09
±0.14
Gain Bandwidth Product
VOUT = 10mVP-P; RL = 10kΩ
IOS
iN
SR
GBW
Electrical Specifications
V
0.16
0.21
V/µs
300
kHz
COMMON ELECTRICAL SPECIFICATIONS V+ = 5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise
specified. For ISL28274 ONLY. Boldface limits apply over the operating temperature range, -40°C to +125°C.
PARAMETER
DESCRIPTION
VOUT
Maximum Output Voltage Swing
CONDITIONS
MIN
(Note 2)
Output low, RL = 100kΩ to VCM
Output low, RL = 1kΩ to VCM
IS,ON
5
Supply Current
TYP
MAX
(Note 2)
UNIT
3
6
30
mV
130
175
225
mV
Output high, RL = 100kΩ to VCM
4.990
4.97
4.996
V
Output high, RL = 1kΩ to VCM
4.800
4.750
4.880
V
ISL28274 All channels
120
156
175
µA
ISL28474 All channels
240
315
350
µA
ISC+
Short Circuit Sourcing Capability
RL = 10Ω to VCM
28
24
31
mA
ISC-
Short Circuit Sinking Capability
RL = 10Ω to VCM
24
20
26
mA
V+
Minimum Supply Voltage
2.4
V
NOTE:
2. Parts are 100% tested at +25°C. Over temperature limits established by characterization and are not production tested.
4
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
90
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified.
90
COMMON-MODE INPUT = V+
COMMON-MODE INPUT = 1/2V+
GAIN = 10,000
GAIN = 10,000
80
80
70
GAIN = 5,000
GAIN = 2,000
GAIN (dB)
GAIN (dB)
GAIN = 5,000
GAIN = 1,000
60
GAIN = 500
50
GAIN = 100
10
GAIN = 1,000
60
GAIN = 500
GAIN = 200
GAIN = 100
40
30
1
GAIN = 2,000
50
GAIN = 200
40
70
100
1k
10k
FREQUENCY (Hz)
100k
30
1M
1
FIGURE 1. AMPLIFIER “A” (IN-AMP) FREQUENCY
RESPONSE vs CLOSED LOOP GAIN
10
100
1k
10k
FREQUENCY (Hz)
100k
FIGURE 2. AMPLIFIER “A” (IN-AMP) FREQUENCY
RESPONSE vs CLOSED LOOP GAIN, VCM = 1/2V+
45
90
COMMON-MODE INPUT = VM +10mV
GAIN = 10,000
40
GAIN = 5,000
35
V+ = 5V
80
70
30
GAIN = 2,000
GAIN (dB)
GAIN (dB)
1M
GAIN = 1,000
60
GAIN = 500
50
40
V+ = 2.4V
25
20
GAIN = 200
15
GAIN = 100
10
AV = 100
RL = 10kΩ
CL = 10pF
RF/RG = 100
RF = 10kΩ
RG = 100Ω
5
30
1
10
100
1k
10k
FREQUENCY (Hz)
100k
0
1M
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
FIGURE 4. AMPLIFIER “A” (IN-AMP) FREQUENCY
RESPONSE vs SUPPLY VOLTAGE
FIGURE 3. AMPLIFIER “A” (IN-AMP) FREQUENCY
RESPONSE vs CLOSED LOOP GAIN
50
120
2200pF
100
45
35
30
25
820pF
AV = 100
R = 10kΩ
CL = 10pF
RF/RG = 100
RF = 10kΩ
RG = 100Ω
10
100
80
CMRR (dB)
GAIN (dB)
1200pF
40
56pF
60
AV = 100
40
20
1k
10k
100k
FREQUENCY (Hz)
FIGURE 5. AMPLIFIER “A” (IN-AMP) FREQUENCY
RESPONSE vs CLOAD
5
1M
0
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
FIGURE 6. AMPLIFIER “A” (IN-AMP) CMRR vs FREQUENCY
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
700
INPUT VOLTAGE NOISE (nV/√Hz)
120
100
PSRR (dB)
80
PSRR+
60
PSRR-
40
AV = 100
20
600
500
400
300
AV = 100
200
100
0
0
10
100
1k
10k
100k
1
1M
10
100
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
FIGURE 8. AMPLIFIER “A” (IN-AMP) INPUT VOLTAGE NOISE
SPECTRAL DENSITY
FIGURE 7. AMPLIFIER “A” (IN-AMP) PSRR vs FREQUENCY
2.0
VOLTAGE NOISE (2µV/DIV)
CURRENT NOISE (pA/√Hz)
1.8
1.6
1.4
1.2
1.0
0.8
AV = 100
0.6
0.4
0.2
0.0
1
10
100
1k
10k
100k
TIME (1s/DIV)
FREQUENCY (Hz)
FIGURE 10. AMPLIFIER “A” (IN-AMP) 0.1Hz TO 10Hz INPUT
VOLTAGE NOISE
FIGURE 9. AMPLIFIER “A” (IN-AMP) INPUT CURRENT
NOISE SPECTRAL DENSITY
45
+1
0
40
GAIN (dB)
-2
V+, V- = ±2.5V
RL = 10k
-3
-4
V+, V- = ±1.2V
RL = 1k
35
V+, V- = ±1.2V
RL = 10k
-5
VOUT = 50mVP-P
-6 AV = 1
CL = 3pF
-7 RF = 0/RG = INF
8
1k
30
GAIN (dB)
V+, V- = ±2.5V
RL = 1k
-1
V+, V- = ±2.5V
25
V+, V- = ±1.2V
20
15
10
5
AV = 100
RL = 10kΩ
CL = 3pF
RF = 100kΩ
RG = 1kΩ
V+, V- = ±1.0V
0
10k
100k
1M
FREQUENCY (Hz)
FIGURE 11. AMPLIFIER “B” (OP-AMP) FREQUENCY
RESPONSE vs SUPPLY VOLTAGE
6
5M
100
1k
10k
100k
1M
FREQUENCY (Hz)
FIGURE 12. AMPLIFIER “B” (OP-AMP) FREQUENCY
RESPONSE vs SUPPLY VOLTAGE
FN6345.3
May 14, 2009
ISL28274, ISL28474
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
80
600
60
400
40
I-BIAS (pA)
100
800
VOS (µV)
1000
200
0
-200
-400
-800
-1000
-1
0
1
2
3
VCM (V)
20
0
-20
-40
V+ = 5V
RL = OPEN
RF = 100k, RG = 100
AV = +1000
-600
V+ = 5V
RL = OPEN
RF= 100k, RG = 100
AV = +1000
-60
-80
4
5
-100
-1
6
FIGURE 13. INPUT OFFSET VOLTAGE vs COMMON MODE
INPUT VOLTAGE
0
1
2
3
VCM (V)
4
5
FIGURE 14. INPUT BIAS CURRENT vs COMMON-MODE
INPUT VOLTAGE
120
80
100
80
40
80
200
150
0
-40
0
GAIN (dB)
PHASE (°)
GAIN (dB)
PHASE
40
-80
-40
-80
1
10
1k
100
10k
100k
1M
50
40
0
20
GAIN
-100
-20
10
-120
10M
100
-10
V+, V- = ±2.5VDC
VSOURCE = 1VP-P
RL = 10kΩ
-20
CMRR (dB)
PSRR (dB)
0
PSRR -
-50
-60
PSRR +
-30
-40
-50
-60
-70
-70
-80
-80
-90
-90
-100
-100
100
-150
1M
10
-30
10
100k
FIGURE 16. AMPLIFIER “B” (OP AMP) AVOL vs FREQUENCY
@ 1kΩ LOAD
V+ = 5VDC
VSOURCE = 1VP-P
RL = 10kΩ
AV = +1
-40
10k
1k
FREQUENCY (Hz)
10
-20
-50
0
FIGURE 15. AMPLIFIER “B” (OP AMP) AVOL vs FREQUENCY
@ 100kΩ LOAD
-10
100
60
FREQUENCY (Hz)
0
6
PHASE (°)
Typical Performance Curves
1k
10k
100k
1M
TEMPERATURE (°C)
FIGURE 17. AMPLIFIER “B” (OP AMP) PSRR vs FREQUENCY
7
10
100
1k
10k
100k
1M
TEMPERATURE (°C)
FIGURE 18. AMPLIFIER “B” (OP AMP) CMRR vs FREQUENCY
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
2.56
5
V+ = 5VDC
VOUT = 2VP-P
RL = 1kΩ
AV = -2
VIN
2.54
4
3
VOUT
2.50
VOLTS (V)
VOLTS (V)
2.52
2.48
V+ = 5VDC
VOUT = 0.1VP-P
2.46
2.42
2
4
6
8
10
VIN
0
AV = +1
0
2
1
RL = 1kΩ
2.44
12
14
16
18
-1
20
0
50
100
150
TIME (µs)
TIME (µs)
200
250
FIGURE 20. AMPLIFIER “B” (OP AMP) LARGE SIGNAL
TRANSIENT RESPONSE
FIGURE 19. AMPLIFIER “B” (OP AMP) SMALL SIGNAL
TRANSIENT RESPONSE
1k
VOLTAGE NOISE (nV/√Hz)
10.00
CURRENT NOISE (pA/√Hz)
VOUT
1.00
0.10
100
10
1
0.01
1
10
100
1k
10k
1
100k
10
100
FIGURE 22. AMPLIFIER “B” (OP AMP) VOLTAGE NOISE vs
FREQUENCY
6
V+ = 5V
VIN
5
VOLTS (V)
VOLTAGE NOISE (1µV/DIV)
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
FIGURE 21. AMPLIFIER “B” (OP AMP) CURRENT NOISE vs
FREQUENCY
10k
1k
4
100K
VS+
100K
3
DUT
+
VOUT
1K
VS -
Function
Generator
33140A
2
1
5.4µVP-P
0
TIME (1s/DIV)
FIGURE 23. AMPLIFIER “B” (OP AMP) 0.1Hz TO 10Hz INPUT
VOLTAGE NOISE
8
0
50
100
150
200
TIME (ms)
FIGURE 24. AMPLIFIER “B” (OP AMP) INPUT VOLTAGE SWING
ABOVE THE V+ SUPPLY
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
155
1V/DIV
SUPPLY CURRENT (µA)
AV = -1
VIN = 200mVP-P
V+ = 5V
V- = 0V
EN
INPUT
135
115
95
0
55
35
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VOUT
0.1V/DIV
75
0
SUPPLY VOLTAGE (V)
10µs/DIV
FIGURE 25. SUPPLY CURRENT vs SUPPLY VOLTAGE
170
FIGURE 26. AMPLIFIER “B” (OP AMP) TO OUTPUT DELAY
TIME
-4.0
n = 100
n = 100
160
MAX
-4.5
MAX
140
CURRENT (µA)
CURRENT (µA)
150
MEDIAN
130
120
110
100
80
-40
-20
0
20
40
60
80
100
-6.5
-40
120
TEMPERATURE (°C)
-20
0
20
40
60
80
100
120
FIGURE 28. DISABLED NEGATIVE SUPPLY CURRENT vs
TEMPERATURE, V+, V- = ±2.5V, RL = INF
40
50
n = 100
MIN
n = 100
MIN
20
0
0
-50
IA FB- IBIAS (pA)
IA FB+ IBIAS (pA)
MIN
TEMPERATURE (°C)
FIGURE 27. TOTAL SUPPLY CURRENT vs TEMPERATURE,
V+, V- = ±2.5V, RL = INF
-100
-150
MEDIAN
-200
-20
-40
-60
-80
MEDIAN
-100
-120
-250
-300
-40
-5.5
-6.0
MIN
90
MEDIAN
-5.0
MAX
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 29. IBIAS (IA FB+) vs TEMPERATURE, V+, V- = ±2.5V
9
MAX
-140
-160
-40
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 30. IBIAS (IA FB-) vs TEMPERATURE, V+, V- = ±2.5V.
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
25
50
n = 100
n = 100
0
IA FB- IBIAS (pA)
IA FB+ IBIAS (pA)
-25
MIN
-75
-125
-175
MEDIAN
-225
-275
-40
0
20
40
60
80
-100
MEDIAN
-150
MAX
-200
MAX
-20
MIN
-50
100
-250
-40
120
-20
0
50
120
n = 100
MEDIAN
IA IN- IBIAS (pA)
IA IN+ IBIAS (pA)
100
0
MIN
-150
-200
-250
MAX
-300
-20
0
20
40
60
80
-50
MIN
-100
-150
MEDIAN
-200
MAX
-250
100
-300
-40
120
-20
0
TEMPERATURE (°C)
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 34. IBIAS (IA IN-) vs TEMPERATURE, V+, V- = ±2.5V
FIGURE 33. IBIAS (IA IN+) vs TEMPERATURE, V+, V- = ±2.5V
50
50
n = 100
n = 100
0
-50
MIN
-100
-150
MEDIAN
-200
MAX
-250
-20
0
20
40
60
80
100
-50
MIN
-100
MEDIAN
-150
MAX
-200
120
TEMPERATURE (°C)
FIGURE 35. IBIAS (IA IN+) vs TEMPERATURE, V+, V- = ±1.2V
10
IA IN- IBIAS (pA)
0
OU
IA IN+ IBIAS (pA)
80
50
-100
-300
-40
60
n = 100
0
-350
-40
40
FIGURE 32. IBIAS (IA FB-) vs TEMPERATURE, V+, V- = ±1.2V
FIGURE 31. IBIAS (IA FB+) vs TEMPERATURE, V+, V- = ±1.2V
-50
20
TEMPERATURE (°C)
TEMPERATURE (°C)
-250
-40
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 36. IBIAS (IA IN-) vs TEMPERATURE, V+, V- = ±1.2V
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
50
30
n = 100
n = 100
10
0
-10
MIN
IN- IBIAS (pA)
IN+ IBIAS (pA)
-50
-100
MEDIAN
-150
-50
MIN
-70
-90
MEDIAN
-110
MAX
-200
-30
MAX
-130
-250
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
100
-150
-40
120
-20
0
20
40
60
80
100
FIGURE 37. IBIAS (IN+) vs TEMPERATURE, V+, V- = ±2.5V
FIGURE 38. IBIAS (IN-) vs TEMPERATURE, V+, V- = ±2.5V
40
40
n = 100
n = 100
-10
-10
MIN
IN- IBIAS (pA)
IN+ IBIAS (pA)
-60
-110
-160
MEDIAN
-210
-60
MIN
-110
MEDIAN
MAX
-160
-210
MAX
-260
-310
-40
-260
-20
0
20
40
60
80
100
-310
-40
120
-20
0
TEMPERATURE (°C)
FIGURE 39. IBIAS (IN+) vs TEMPERATURE, V+, V- = ±1.2V
MAX
100
120
50
n = 100
20.0
20
40
60
80
TEMPERATURE (°C)
FIGURE 40. IBIAS (IN-) vs TEMPERATURE, V+, V- = ±1.2V
40.0
n = 100
40
30
-20.0
IA IOS (pA)
0.0
IA IOS (pA)
120
TEMPERATURE (°C)
MIN
-40.0
MEDIAN
-60.0
-80.0
20
10
MAX
0
-10
-20
-100.0
-30
-120.0
-40
-140.0
-40
-50
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 41. IA INPUT OFFSET CURRENT vs TEMPERATURE,
V+, V- = ±2.5V
11
MEDIAN
MIN
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 42. IA INPUT OFFSET CURRENT vs TEMPERATURE,
V+, V- = ±1.2V
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
100
40
n = 100
n = 100
MAX
20
MAX
50
0
-20
IOS (pA)
IOS (pA)
0
-50
-40
-60
MEDIAN
-100
-80
-100
-150
MEDIAN
MIN
-120
-200
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
MIN
IA VOS (µV)
IA VOS (µV)
-200
MEDIAN
-600
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
n = 100
200
0
-200
100
-800
-40
120
MEDIAN
MAX
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 46. IA INPUT OFFSET VOLTAGE vs TEMPERATURE
V+, V- = ±1.2V
500
n = 100
400
300
n = 100
MIN
300
MIN
200
200
100
100
VOS (µV)
VOS (µV)
80
MIN
-600
MAX
FIGURE 45. IA INPUT OFFSET VOLTAGE vs TEMPERATURE,
V+, V- = ±2.5V
0
MEDIAN
0
-100
MEDIAN
-200
-300
-300
MAX
-400
-500
-40
60
-400
-400
-200
40
400
0
-100
20
600
200
400
0
800
n = 100
400
500
-20
FIGURE 44. INPUT OFFSET CURRENT vs TEMPERATURE,
V+, V- = ±1.2V
600
-800
-40
MIN
TEMPERATURE (°C)
FIGURE 43. INPUT OFFSET CURRENT vs TEMPERATURE,
V+, V- = ±2.5V
800
-1400
-40
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 47. INPUT OFFSET VOLTAGE vs TEMPERATURE,
V+, V- = ±2.5V
12
MAX
-400
-500
-40
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 48. INPUT OFFSET VOLTAGE vs TEMPERATURE,
V+, V- = ±1.2V
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
140
145
n = 100
n = 100
135
130
CMRR (dB)
MIN
125
IA CMRR (dB)
MIN
115
MEDIAN
105
120
110
MEDIAN
100
95
MAX
90
85
75
-40
MAX
-20
0
20
40
60
80
100
80
-40
120
-20
0
20
TEMPERATURE (°C)
155
n = 100
145
120
n = 100
125
115
MEDIAN
105
MIN
135
PSRR (dB)
IA PSRR (dB)
MIN
95
125
115
MEDIAN
105
95
MAX
85
MAX
85
-20
0
20
40
60
80
100
75
-40
120
-20
0
TEMPERATURE (°C)
4.910
4.9975
MIN
MIN
IA VOUT (V)
4.890
4.880
MEDIAN
4.9970
4.9965
4.9960
MEDIAN
MAX
MAX
4.9955
4.850
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 53. IA VOUT HIGH vs TEMPERATURE, RL = 1k,
V+, V- = ±2.5V
13
120
n = 100
4.900
-20
100
4.9980
n = 100
4.860
20
40
60
80
TEMPERATURE (°C)
FIGURE 52. PSRR vs TEMPERATURE, V+, V- = ±2.5V
FIGURE 51. IA PSRR vs TEMPERATURE, V+, V- = ±2.5V
IA VOUT (V)
100
145
135
4.840
-40
80
FIGURE 50. CMRR vs TEMPERATURE, VCM = +2.5V TO -2.5V
155
4.870
60
TEMPERATURE (°C)
FIGURE 49. IA CMRR vs TEMPERATURE,
VCM = +2.5V TO -2.5V
75
-40
40
4.9950
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 54. IA VOUT HIGH vs TEMPERATURE, RL = 100k,
V+, V- = ±2.5V
FN6345.3
May 14, 2009
ISL28274, ISL28474
Typical Performance Curves
170
V+ = +5V, V- = GND, VCM = 1/2V+, TA = +25°C, unless otherwise specified. (Continued)
6.5
n = 100
n = 100
160
6.0
MIN
IA VOUT (mV)
IA VOUT (mV)
150
140
130
MEDIAN
120
5.5
MIN
5.0
MEDIAN
4.5
110
MAX
100
90
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
100
3.5
-40
120
FIGURE 55. IA VOUT LOW vs TEMPERATURE, RL = 1k,
V+, V- = ±2.5V
0
20
40
60
80
TEMPERATURE (°C)
100
120
4.9986
n = 100
n = 100
4.9984
4.900
4.9982
MIN
MIN
4.9980
VOUT (V)
4.890
VOUT (V)
-20
FIGURE 56. IA VOUT LOW vs TEMPERATURE, RL = 100k,
V+, V- = ±2.5V
4.910
4.880
4.870
MAX
4.0
MEDIAN
4.9978
4.9976
4.9974
MEDIAN
4.9972
MAX
4.9970
MAX
4.860
4.9968
4.850
-40
-20
0
20
40
60
80
100
120
4.9966
-40
-20
0
TEMPERATURE (°C)
FIGURE 57. VOUT HIGH vs TEMPERATURE, RL = 1k,
V+, V- = ±2.5V
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 58. VOUT HIGH vs TEMPERATURE, RL = 100k,
V+, V- = ±2.5V
170
n = 100
4.4
160
MIN
4.0
140
130
VOUT (mV)
VOUT (mV)
4.2
MIN
150
MEDIAN
120
MAX
110
3.8
3.6
MEDIAN
3.4
MAX
3.2
100
90
-40
n = 100
-20
0
20
40
60
80
100
TEMPERATURE (°C)
FIGURE 59. VOUT LOW vs TEMPERATURE, RL = 1k,
V+, V- = ±2.5V
14
120
3.0
-40
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 60. VOUT LOW vs TEMPERATURE RL = 100k, V+, V= ±2.5V
FN6345.3
May 14, 2009
ISL28274, ISL28474
Pin Descriptions
ISL28274
ISL28474
(16 LD QSOP) (24 LD QSOP)
1, 9, 13, 14
EQUIVALENT
CIRCUIT
DESCRIPTION
11, 14
NC
IA OUT
IA OUT_1
IA OUT_2
Circuit 2
Instrumentation Amplifier output
1, 24
IA FB+
IA FB+_1
IA FB+_2
Circuit 1
Instrumentation Amplifier Feedback from non-inverting output
2, 23
IA FBIA FB-_1
IA FB-_2
Circuit 1
Instrumentation Amplifier Feedback from inverting output
3, 22
IA INIA IN-_1
IA IN-_2
Circuit 1
Instrumentation Amplifier inverting input
4, 21
IA IN+
IA IN+_1
IA IN+_2
Circuit 1
Instrumentation Amplifier non-inverting input
5, 20
6, 19
DNC
2
3
4
5
6
7
PIN NAME
No internal connection
Do Not Connect, Internal connection - Must be left floating
8
18
V-
10
8, 17
DNC
IN+
IN+ 1
IN+ 2
Circuit 1
Amplifier non-inverting input
9, 16
ININ- 1
IN- 2
Circuit 1
Amplifier inverting input
10, 15
OUT
OUT 1
OUT 2
Circuit 2
Amplifier output
12, 13
7
V+
Circuit 3
Positive power supply
11
12
15
16
Circuit 3
Negative power supply
Do Not Connect, Internal connection - Must be left floating
IA = Instrumentation Amplifier
V+
IN-
V+
V-
V-
VCIRCUIT 2
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
60µA 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
15
CAPACITIVELY
COUPLED
ESD CLAMP
OUT
IN+
CIRCUIT 1
V+
CIRCUIT 3
level, the in-amp achieves 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.
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. An external
series resistor may be used as a protection to limit excessive
external voltage and current from damaging the inputs.
FN6345.3
May 14, 2009
ISL28274, ISL28474
Input Stage and Input Voltage Range
Reference Connection
The input terminals (IN+ and IN-) of both amplifiers “A” and
“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.
Unlike a three-op amp 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 62 uses the FB+
pin to provide a high impedance REF terminal.
A pair of complementary MOSFET devices drives the output
VOUT to within a few mV of the supply rails. At a 100kΩ 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.
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
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
6 IN+
5 INVIN/2
3 FB+
VCM
4 FB-
7
AMP “A”
V+
+
-
ISL28274
2
VOUT
+
-
16
VIN/2
6 IN+
5 IN-
7
V+
+
AMP “A”
-
VIN/2
3 FB+
VCM
Output Stage and Output Voltage Range
VIN/2
2.4V TO 5V
4 FB-
2.4V to 5V
ISL28274
2
VOUT
+
-
V8
R1
REF
R2
RG
RF
FIGURE 62. GAIN SETTING AND REFERENCE CONNECTION
RF ⎞
RF ⎞
⎛
⎛
VOUT = ⎜ 1 + --------⎟ ( VIN ) + ⎜ 1 + --------⎟ ( VREF )
R G⎠
R G⎠
⎝
⎝
(EQ. 2)
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 62.
The FB+ pin can also be connected to the other end of resistor,
RG. See Figure 63. 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 63 can be derived.
V-
2.4V TO 5V
8
16
VIN/2
RG
6 IN+
RF
5 INVIN/2
3 FB+
FIGURE 61. GAIN IS BY EXTERNAL RESISTORS RF AND RG
VCM
4 FB-
7
V+
+
-
ISL28274
AMP “A”
2
VOUT
+
-
V8
RF ⎞
⎛
VOUT = ⎜ 1 + --------⎟ VIN
R G⎠
⎝
(EQ. 1)
RG
In Figure 61, the FB+ pin and one end of resistor RG are
connected to GND. With this configuration, Equation 1 is
only true for a positive swing in VIN; negative input swings
will be ignored and the output will be at ground.
16
RF
VREF
FIGURE 63. REFERENCE CONNECTION WITH AN AVAILABLE
VREF
FN6345.3
May 14, 2009
ISL28274, ISL28474
RF ⎞
⎛
VOUT = ⎜ 1 + --------⎟ ( VIN ) + ( VREF )
R
⎝
G⎠
(EQ. 3)
HIGH IMPEDANCE INPUT
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 Equation 3
for Figure 63. VOUT is simply shifted by an amount VREF.
V+
IN
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 op amp and
especially a two op amp in-amp, the ISL28274 reduces 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 65. GUARD RING EXAMPLE FOR UNITY GAIN
AMPLIFIER
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.
Using Only the Instrumentation Amplifier
Power Dissipation
If the application only requires the instrumentation amp, the
user must configure the unused op amp to prevent it from
oscillating. The unused op amp 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 64).
It is possible to exceed the +150°C 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 4:
T JMAX = T MAX + ( θ JA xPD MAXTOTAL )
(EQ. 4)
-
where:
+
• PDMAXTOTAL is the sum of the maximum power
dissipation of each amplifier in the package (PDMAX)
FIGURE 64. PREVENTING OSCILLATIONS IN UNUSED
CHANNELS
Proper Layout Maximizes Performance
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 65 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.
17
• PDMAX for each amplifier can be calculated as shown in
Equation 5:
V OUTMAX
PD MAX = 2*V S × I SMAX + ( V S - V OUTMAX ) × ---------------------------RL
(EQ. 5)
where:
• TMAX = Maximum ambient temperature
• θJA = Thermal resistance of the package
• PDMAX = Maximum power dissipation of 1 amplifier
• VS = Supply voltage (Magnitude of V+ and V-)
• IMAX = Maximum supply current of 1 amplifier
• VOUTMAX = Maximum output voltage swing of the
application
• RL = Load resistance
FN6345.3
May 14, 2009
ISL28274, ISL28474
Quarter Size Outline Plastic Packages Family (QSOP)
MDP0040
A
QUARTER SIZE OUTLINE PLASTIC PACKAGES FAMILY
D
(N/2)+1
N
INCHES
SYMBOL QSOP16 QSOP24 QSOP28 TOLERANCE NOTES
E
PIN #1
I.D. MARK
E1
1
(N/2)
A
0.068
0.068
0.068
Max.
-
A1
0.006
0.006
0.006
±0.002
-
A2
0.056
0.056
0.056
±0.004
-
b
0.010
0.010
0.010
±0.002
-
c
0.008
0.008
0.008
±0.001
-
D
0.193
0.341
0.390
±0.004
1, 3
E
0.236
0.236
0.236
±0.008
-
E1
0.154
0.154
0.154
±0.004
2, 3
e
0.025
0.025
0.025
Basic
-
L
0.025
0.025
0.025
±0.009
-
L1
0.041
0.041
0.041
Basic
-
N
16
24
28
Reference
-
B
0.010
C A B
e
H
C
SEATING
PLANE
0.007
0.004 C
b
C A B
Rev. F 2/07
NOTES:
L1
A
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.
c
SEE DETAIL "X"
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
A1
4°±4°
DETAIL X
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
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