DATASHEET

ISL28138, ISL28238
®
Data Sheet
February 19, 2008
4.5MHz, Single and Dual Precision
Rail-to-Rail Input-Output (RRIO) Op Amps
with Very Low Input Bias Current
The ISL28138 and ISL28238 are 4.5MHz low-power single
and dual operational amplifiers. The parts are optimized for
single supply operation from 2.4V to 5.5V, allowing operation
from one lithium cell or two Ni-Cd batteries.
The parts feature an Input Range Enhancement Circuit
(IREC) which enables them to maintain CMRR performance
for input voltages greater than the positive supply. The input
signal is capable of swinging 0.25V above the positive
supply and to 100mV below the negative supply with only a
slight degradation of the CMRR performance. The output
operation is rail-to-rail.
The parts draw minimal supply current (900µA per amplifier)
while meeting excellent DC accuracy, AC performance,
noise and output drive specifications. The ISL28138 features
an enable pin that can be used to turn the device off and
reduce the supply current to less than 20µA. Operation is
guaranteed over -40°C to +125°C temperature range.
ISL28138FHZ-T7*
PART
MARKING
Features
• 4.5MHz gain bandwidth product
• 900µA supply current (per amplifier)
• 300µV maximum offset voltage
• 1pA typical input bias current
• Down to 2.4V single supply voltage range
• Rail-to-rail input and output
• Output sources and sinks 60mA load current
• Enable pin (ISL28138)
• -40°C to +125°C operation
• Pb-free (RoHS compliant)
Applications
• Low-end audio
• 4mA to 20mA current loops
• Medical devices
• Sensor amplifiers
Ordering Information
PART NUMBER
(Note)
• ADC buffers
PACKAGE
(Pb-free)
PKG. DWG. #
GABR
6 Ld SOT-23
MDP0038
ISL28138FHZ-T7A* GABR
6 Ld SOT-23
MDP0038
ISL28138FBZ
28138 FBZ 8 Ld SOIC
MDP0027
ISL28138FBZ-T7*
28138 FBZ 8 Ld SOIC
MDP0027
Coming Soon
ISL28238FBZ
28238 FBZ 8 Ld SOIC
MDP0027
Coming Soon
ISL28238FBZ-T7*
28238 FBZ 8 Ld SOIC
MDP0027
Coming Soon
ISL28238FUZ
8238Z
8 Ld MSOP
MDP0043
Coming Soon
ISL28238FUZ-T7*
8238Z
8 Ld MSOP
MDP0043
• DAC output amplifiers
Pinouts
OUT 1
V- 2
+ -
6 V+
NC 1
5 EN
IN- 2
4 IN-
IN+ 3
8 EN
7 V+
+
6 OUT
V- 4
OUT_A 1
IN-_A 2
IN+_A 3
V- 4
8 V+
- +
+ -
5 NC
ISL28238
(8 LD MSOP)
TOP VIEW
ISL28238
(8 LD SO)
TOP VIEW
*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.
ISL28138
(8 LD SO)
TOP VIEW
ISL28138
(6 LD SOT-23)
TOP VIEW
IN+ 3
1
FN6336.2
OUT_A 1
7 OUT_B
IN-_A 2
6 IN-_B
IN+_A 3
5 IN+_B
V- 4
8 V+
7 OUT_B
- +
+ -
6 IN-_B
5 IN+_B
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. 2007, 2008. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
ISL28138, ISL28238
Absolute Maximum Ratings (TA = +25°C)
Thermal Information
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.75V
Supply Turn On Voltage Slew Rate . . . . . . . . . . . . . . . . . . . . . 1V/µs
Differential Input Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mA
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . V- - 0.5V to V+ + 0.5V
ESD Tolerance
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3kV
Machine Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300V
Thermal Resistance
θJA (°C/W)
6 Ld SOT-23 Package . . . . . . . . . . . . . . . . . . . . . . .
230
8 Ld SOIC Package . . . . . . . . . . . . . . . . . . . . . . . .
110
8 Ld MSOP Package . . . . . . . . . . . . . . . . . . . . . . . .
115
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.
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
V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, TA = +25°C unless otherwise specified.
Boldface limits apply over the operating temperature range, -40°C to +125°C. Temperature data
established by characterization.
DESCRIPTION
Input Offset Voltage
ΔV OS
--------------ΔT
Input Offset Voltage vs Temperature
IOS
Input Offset Current
IB
CONDITIONS
MIN
(Note 1)
TYP
MAX
(Note 1)
UNIT
8 Ld SOIC
-300
-650
±6
300
650
µV
6 Ld SOT-23
-550
-750
±6
550
750
µV
8 Ld SOIC
0.6
µV/°C
-35
-80
±5
35
80
pA
TA = -40°C to +85°C
-30
-80
±1
30
80
pA
TA = -40°C to +85°C
5
V
Input Bias Current
CMIR
Common-Mode Voltage Range
Guaranteed by CMRR
0
CMRR
Common-Mode Rejection Ratio
VCM = 0V to 5V
75
70
98
dB
PSRR
Power Supply Rejection Ratio
V+ = 2.4V to 5.5V
80
75
98
dB
AVOL
Large Signal Voltage Gain
VO = 0.5V to 4.5V, RL = 100kΩ to VCM
200
150
580
V/mV
VO = 0.5V to 4.5V, RL = 1kΩ to VCM
50
V/mV
Output low, RL = 100kΩ to VCM
3
6
8
mV
Output low, RL = 1kΩ to VCM
50
70
110
mV
VOUT
Maximum Output Voltage Swing
IS,ON
Supply Current, Enabled
IS,OFF
Supply Current, Disabled (ISL28138)
2
Output high, RL = 100kΩ to VCM
4.994
4.99
4.998
V
Output high, RL = 1kΩ to VCM
4.93
4.89
4.95
V
0.7
0.4
0.9
1.1
1.4
mA
10
14
16
µA
FN6336.2
February 19, 2008
ISL28138, ISL28238
Electrical Specifications
PARAMETER
V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, TA = +25°C unless otherwise specified.
Boldface limits apply over the operating temperature range, -40°C to +125°C. Temperature data
established by characterization. (Continued)
DESCRIPTION
CONDITIONS
MIN
(Note 1)
TYP
MAX
(Note 1)
UNIT
IO+
Short-Circuit Output Source Current
RL = 10Ω
48
45
75
mA
IO-
Short-Circuit Output Sink Current
RL = 10Ω
50
45
68
mA
VSUPPLY
Supply Operating Range
V+ to V-, Guararteed by PSRR
2.4
VENH
EN Pin High Level (ISL28138)
VENL
EN Pin Low Level(ISL28138)
IENH
EN Pin Input High Curren (ISL28138)
VEN = V+
IENL
EN Pin Input Low Current (ISL28138)
5.5
2
V
V
0.8
V
1
1.5
1.6
µA
VEN = V-
12
25
30
nA
AC SPECIFICATONS
GBW
Gain Bandwidth Product
AV = 100, RF = 100kΩ, RG = 1kΩ,
RL = 10kΩ to VCM
4.5
MHz
Unity Gain
Bandwidth
-3dB Bandwidth
AV =1, RF = 0Ω, VOUT = 10mVP-P,
RL = 10kΩ to VCM
13
MHz
eN
Input Noise Voltage Peak-to-Peak
f = 0.1Hz to 10Hz
2
µVP-P
Input Noise Voltage Density
fO = 1kHz
26
nV/√Hz
Input Noise Current Density
fO = 1kHz
0.12
pA/√Hz
iN
CMRR @ 60Hz Input Common Mode Rejection Ratio
VCM = 1VP-P, RL = 10kΩ to VCM
85
dB
PSRR- @
120Hz
Power Supply Rejection Ratio (V-)
V+, V- = ±1.2V and ±2.5V,
VSOURCE = 1VP-P, RL = 10kΩ to VCM
-82
dB
PSRR+ @
120Hz
Power Supply Rejection Ratio (V+)
V+, V- = ±1.2V and ±2.5V
VSOURCE = 1VP-P, RL = 10kΩ to VCM
-100
dB
±4.8
V/µs
TRANSIENT RESPONSE
SR
Slew Rate
tr, tf, Large
Signal
Rise Time, 10% to 90%, VOUT
AV = +2, VOUT = 3VP-P, RG = RF = 10kΩ
RL = 10kΩ to VCM
530
ns
Fall Time, 90% to 10%, VOUT
AV = +2, VOUT = 3VP-P, RG = RF = 10kΩ
RL = 10kΩ to VCM
530
ns
Rise Time, 10% to 90%, VOUT
AV = +2, VOUT = 10mVP-P,
RG = RF = RL = 10kΩ to VCM
50
ns
Fall Time, 90% to 10%, VOUT
AV = +2, VOUT = 10mVP-P,
RG = RF = RL = 10kΩ to VCM
50
ns
Enable to Output Turn-on Delay Time, 10%
EN to 10% VOUT, (ISL28138)
VEN = 5V to 0V, AV = +2,
RG = RF = RL = 1k to VCM
5
µs
Enable to Output Turn-off Delay Time, 10%
EN to 10% VOUT, (ISL28138)
VEN = 0V to 5V, AV = +2,
RG = RF = RL = 1k to VCM
0.2
µs
tr, tf, Small
Signal
tEN
NOTE:
1. Parts are 100% tested at +25°C. Temperature limits established by characterization and are not production tested.
3
FN6336.2
February 19, 2008
ISL28138, ISL28238
Typical Performance Curves V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, unless otherwise specified.
1
15
Rf = Rg = 100k
Rf = Rg = 10k
5
0
V+ = 5V
-5 RL = 1k
CL = 16.3pF
-10 AV = +2
VOUT = 10mVP-P
-15
100
1k
10k
Rf = Rg = 1k
100k
1M
10M
NORMALIZED GAIN (dB)
NORMALIZED GAIN (dB)
0
10
100M
VOUT = 100mV
-1
-2
VOUT = 50mV
-3
VOUT = 10mV
-4
VOUT = 1V
-5
-6 V = 5V
+
-7 RL = 1k
CL = 16.3pF
-8
AV = +1
-9
1k
10k
FREQUENCY (Hz)
1
1
0
0
VOUT = 100mV
-2
VOUT = 50mV
-3
VOUT = 10mV
-4
VOUT = 1V
-5
-6
V+ = 5V
RL = 10k
CL = 16.3pF
AV = +1
-7
-8
-9
1k
10k
-2
VOUT = 50mV
-3
VOUT = 10mV
-4
10M
VOUT = 1V
-6
V+ = 5V
RL = 100k
CL = 16.3pF
AV = +1
-7
1k
100M
10k
FREQUENCY (Hz)
AV = 101
RL = 100k
-3
-4
-5
-6
-7
-8
-9
V+ = 5V
VOUT = 10mVP-P
CL = 16.3pF
AV = +1
1k
10k
100M
AV = 1, Rg = INF, Rf = 0
AV = 10, Rg = 1k, Rf = 9.09k
AV = 101, Rg = 1k, Rf = 100k
AV = 1001, Rg = 1k, Rf = 1M
AV = 1001
50
GAIN (dB)
NORMALIZED GAIN (dB)
RL = 10k
-2
10M
70
60
-1
1M
FIGURE 4. GAIN vs FREQUENCY vs VOUT, RL = 100k
RL = 1k
0
100k
FREQUENCY (Hz)
FIGURE 3. GAIN vs FREQUENCY vs VOUT, RL = 10k
1
100M
-5
-9
1M
10M
VOUT = 100mV
-1
-8
100k
1M
FIGURE 2. GAIN vs FREQUENCY vs VOUT, RL = 1k
NORMALIZED GAIN (dB)
NORMALIZED GAIN (dB)
FIGURE 1. GAIN vs FREQUENCY vs FEEDBACK RESISTOR
VALUES Rf/Rg
-1
100k
FREQUENCY (Hz)
40
V+ = 5V
CL = 16.3pF
RL = 10k
VOUT = 10mVP-P
30
AV = 10
20
10
0
100k
1M
10M
FREQUENCY (Hz)
FIGURE 5. GAIN vs FREQUENCY vs RL
4
100M
-10
100
AV = 1
1k
10k
100k
1M
10M
100M
FREQUENCY (Hz)
FIGURE 6. FREQUENCY RESPONSE vs CLOSED LOOP GAIN
FN6336.2
February 19, 2008
ISL28138, ISL28238
Typical Performance Curves V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, unless otherwise specified.
1
V+ = 5V
-1
-2
V+ = 2.4V
-3
-4
-5
-6
-7
-8
RL = 10k
CL = 16.3pF
AV = +1
VOUT = 10mVP-P
-9
10k
100k
1M
10M
NORMALIZED GAIN (dB)
NORMALIZED GAIN (dB)
0
100M
8
7
6
5
4
3
2
1
0
-1
-2
-3 V+ = 5V
-4 RL = 1k
-5 A = +1
V
-6
VOUT = 10mVP-P
-7
-8
10k
100k
FREQUENCY (Hz)
(Continued)
CL = 51.7pF
CL = 43.7pF
CL = 37.7pF
CL = 26.7pF
CL = 16.7pF
CL = 4.7pF
1M
10M
100M
FREQUENCY (Hz)
FIGURE 8. GAIN vs FREQUENCY vs CL
FIGURE 7. GAIN vs FREQUENCY vs SUPPLY VOLTAGE
20
10
0
0
-10
PSRR (dB)
-40
-50
V+ = 2.4V, 5V
RL = 1k
CL = 16.3pF
AV = +1
VCM = 1VP-P
-60
-70
-80
1k
10k
100k
FREQUENCY (Hz)
1M
-60
PSRR+
-80
-100
10M
-120
100
1k
10k
100k
V+, V- = ±1.2V
RL = 1k
CL = 16.3pF
AV = +1
VCM = 1VP-P
1M
10M
FREQUENCY (Hz)
FIGURE 9. CMRR vs FREQUENCY; V+ = 2.4V AND 5V
FIGURE 10. PSRR vs FREQUENCY, V+, V- = ±1.2V
20
1k
0
PSRR-
-20
PSRR (dB)
-40
-40
-60
PSRR+
-80
-100
-120
100
1k
10k
100k
V+, V- = ±2.5V
RL = 1k
CL = 16.3pF
AV = +1
VCM = 1VP-P
1M
10M
FREQUENCY (Hz)
FIGURE 11. PSRR vs FREQUENCYV, V+, V- = ±2.5V
5
INPUT VOLTAGE NOISE (nV/√Hz)
CMRR (dB)
-30
-90
100
PSRR-
-20
-20
V+ = 5V
RL = 1k
CL = 16.3pF
AV = +1
100
10
1
10
100
1k
FREQUENCY (Hz)
10k
100k
FIGURE 12. INPUT VOLTAGE NOISE DENSITY vs FREQUENCY
FN6336.2
February 19, 2008
ISL28138, ISL28238
Typical Performance Curves V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, unless otherwise specified.
0
10
V+ = 5V
RL = 1k
CL = 16.3pF
AV = +1
-0.5
INPUT NOISE (µV)
INPUT CURRENT NOISE (pA/√Hz)
(Continued)
1
-1.0
-1.5
-2.0
RL = 10k
V+ = 5V
CL = 16.3pF AV = 10k
Rf = 100k
Rg = 10
-2.5
-3.0
0.1
1
10
100
1k
FREQUENCY (Hz)
10k
100k
0
1
2
3
4
5
6
TIME (s)
7
8
9
10
FIGURE 14. INPUT VOLTAGE NOISE 0.1Hz to 10Hz
FIGURE 13. INPUT CURRENT NOISE DENSITY vs FREQUENCY
2.0
0.025
SMALL SIGNAL (V)
1.0
0.5
0
V+, V- = ±2.5V
RL = 1k
CL = 16.3pF
Rg = Rf =10k
AV = 2
VOUT = 3VP-P
-1.0
-1.5
-2.0
0
1
2
3
4
5
6
TIME (µs)
7
8
9
0.020
0.010
10
V+, V- = ±2.5V
RL = 1k
CL = 16.3pF
Rg= Rf = 10k
AV = 2
VOUT = 10mVP-P
0.015
0
1
2
3
4
5
6
7
8
9
10
TIME (µs)
FIGURE 15. LARGE SIGNAL STEP RESPONSE
FIGURE 16. SMALL SIGNAL STEP RESPONSE
1.2
3.5
VOUT
VEN
3.0
1.0
2.5
0.8
V+ = 5V
Rg = Rf = 10k
CL = 16.3pF
AV = +2
VOUT = 1VP-P
2.0
1.5
1.0
0.5
0.6
0.4
0.2
RL = 10k
0
0
-0.5
OUTPUT (V)
-0.5
VENABLE (V)
LARGE SIGNAL (V)
1.5
0
10
20
30
40
50
60
TIME (µs)
70
80
90
-0.2
100
FIGURE 17. ISL28138 ENABLE TO OUTPUT RESPONSE
6
FN6336.2
February 19, 2008
ISL28138, ISL28238
Typical Performance Curves V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, unless otherwise specified.
800
100
V+ = 5V
RL = OPEN
Rf = 100k, Rg = 100
AV = +1k
600
400
V+ = 5V
RL = OPEN
Rf = 100k, Rg = 100
AV = +1k
80
60
40
200
IBIAS (pA)
VOS (µV)
(Continued)
0
-200
20
0
-20
-40
-400
-60
-600
-800
-1
-80
0
1
2
3
VCM (V)
4
5
6
FIGURE 18. INPUT OFFSET VOLTAGE vs COMMON MODE
INPUT VOLTAGE
-100
2
3
VCM (V)
4
5
6
MAX
9.5
MAX
CURRENT (µA)
CURRENT (µA)
1
10.5
1.1
1.0
MEDIAN
0.9
0.8
MIN
0.7
8.5
MEDIAN
7.5
6.5
MIN
5.5
4.5
-20
0
20
40
60
80
TEMPERATURE (°C)
100
3.5
-40
120
FIGURE 20. SUPPLY CURRENT ENABLED vs
TEMPERATURE V+, V- = ±2.5V
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
100
120
FIGURE 21. SUPPLY CURRENT DISABLED vs
TEMPERATURE V+, V- = ±2.5V
800
600
600
400
MAX
MEDIAN
0
-200
MAX
400
VOS (µV)
200
VOS (µV)
0
FIGURE 19. INPUT BIAS CURRENT vs COMMON MODE
INPUT VOLTAGE
1.2
0.6
-40
-1
MIN
-400
200
MEDIAN
0
-200
-400
MIN
-600
-800
-40
-600
-20
0
20
40
60
80
TEMPERATURE (°C)
FIGURE 22. VOS (SOIC PKG) vs TEMPERATURE
VIN = 0V, V+, V- = ±2.75V
7
100
120
-800
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
FIGURE 23. VOS (SOT PKG) vs TEMPERATURE
VIN = 0V, V+, V- = ±2.75V
FN6336.2
February 19, 2008
ISL28138, ISL28238
Typical Performance Curves V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, unless otherwise specified.
800
600
600
400
400
VOS (µV)
VOS (µV)
MEDIAN
0
-200
MIN
-400
-20
0
20
40
60
80
TEMPERATURE (°C)
100
-200
-800
-40
120
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
100
120
1000
600
800
MAX
200
MEDIAN
0
-200
MIN
400
200
-200
-600
-400
0
20
40
60
80
TEMPERATURE (°C)
100
-600
-40
120
FIGURE 26. VOS (SOIC PKG) vs TEMPERATURE
VIN = 0V, V+, V- = ±1.2V
250
250
200
IBIAS- (pA)
MAX
150
MIN
-20
0
MEDIAN
100
MAX
150
MEDIAN
100
50
50
20
40
60
80
TEMPERATURE (°C)
FIGURE 27. VOS (SOT PKG) vs TEMPERATURE
VIN = 0V, V+, V- = ±1.2V
300
200
MEDIAN
0
-400
-20
MAX
600
VOS (µV)
400
MIN
MIN
0
0
-50
-40
MIN
FIGURE 25. VOS (SOT PKG) vs TEMPERATURE
VIN = 0V, V+, V- = ±2.5V
800
VOS (µV)
MEDIAN
0
-600
FIGURE 24. VOS (SOIC PKG) vs TEMPERATURE
VIN = 0V, V+, V- = ±2.5V
IBIAS- (pA)
200
-400
-600
-800
-40
MAX
MAX
200
-800
-40
(Continued)
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 28. IBIAS- vs TEMPERATURE V+, V- = ±2.5V
8
-50
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 29. IBIAS- vs TEMPERATURE V+, V- = ±1.2V
FN6336.2
February 19, 2008
ISL28138, ISL28238
Typical Performance Curves V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, unless otherwise specified.
10
20
0
10
MAX
-20
0
MEDIAN
-30
IOS (pA)
IOS (pA)
-10
MIN
-40
-10
MAX
-20
MEDIAN
-30
-50
-40
-60
-50
-70
-40
(Continued)
-20
0
20
40
60
80
TEMPERATURE (°C)
100
-60
-40
120
FIGURE 30. IOS vs TEMPERATURE V+, V- = ±2.5V
MIN
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 31. IOS vs TEMPERATURE V+, V- = ±1.2V
80
1750
70
1350
AVOL (V/mV)
AVOL (V/mV)
1550
1150
950
MAX
750
550
MEDIAN
60
MAX
50
MEDIAN
40
30
MIN
350
150
-40
MIN
-20
0
20
40
60
80
TEMPERATURE (°C)
100
20
-40
120
140
20
40
60
80
TEMPERATURE (°C)
100
120
100
120
140
MAX
130
130
MAX
120
PSRR (dB)
120
CMRR (dB)
0
FIGURE 33. AVOL vs TEMPERATURE, RL = 1k
V+, V- = ±2.5V, VO = -2V TO +2V
FIGURE 32. AVOL vs TEMPERATURE, RL = 100k,
V+, V- = ±2.5V, VO = -2V TO +2V
110
MEDIAN
100
90
110
100
MEDIAN
90
MIN
MIN
80
80
70
-40
-20
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 34. CMRR vs TEMPERATURE, VCM = +2.5V TO -2.5V,
V+, V- = ±2.5V
9
70
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
FIGURE 35. PSRR vs TEMPERATURE, V+, V- = ±1.2V TO
±2.75V
FN6336.2
February 19, 2008
ISL28138, ISL28238
Typical Performance Curves V+ = 5V, V- = 0V,VCM = 2.5V, RL = Open, unless otherwise specified.
4.970
4.9994
4.965
4.9992
MAX
MAX
4.9990
VOUT (V)
VOUT (V)
4.960
4.955
MEDIAN
4.945
0
4.9984
20
40
60
80
TEMPERATURE (°C)
100
75
3.3
70
3.1
MEDIAN
55
MIN
100
120
MAX
2.7
2.5
2.3
MEDIAN
MIN
1.9
45
1.7
0
20
40
60
80
TEMPERATURE (°C)
100
90
MAX
85
80
MEDIAN
75
70
MIN
65
0
20
40
60
80
TEMPERATURE (°C)
100
FIGURE 40. + OUTPUT SHORT CIRCUIT CURRENT vs
TEMPERATURE VIN = -2.55V, RL = 10,
V+, V- = ±2.5V
10
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 39. VOUT LOW vs TEMPERATURE RL=100k,
V+, V- = ±2.5V
95
-20
1.5
-40
120
120
- OUTPUT SHORT CIRCUIT CURRENT (mA)
-20
FIGURE 38. VOUT LOW vs TEMPERATURE RL = 1k,
V+, V- = ±2.5V
+ OUTPUT SHORT CIRCUIT CURRENT (mA)
20
40
60
80
TEMPERATURE (°C)
2.1
50
60
-40
0
2.9
MAX
60
40
-40
-20
FIGURE 37. VOUT HIGH vs TEMPERATURE RL = 100k,
V+, V- = ±2.5V
VOUT (mV)
VOUT (mV)
4.9982
-40
120
FIGURE 36. VOUT HIGH vs TEMPERATURE RL = 1k,
V+, V- = ±2.5V
65
MEDIAN
MIN
MIN
-20
4.9988
4.9986
4.950
4.940
-40
(Continued)
-50
-55
MAX
-60
MEDIAN
-65
-70
MIN
-75
-80
-85
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
100
120
FIGURE 41. - OUTPUT SHORT CIRCUIT CURRENT vs
TEMPERATURE VIN = -2.55V, RL = 10,
V+, V- = ±2.5V
FN6336.2
February 19, 2008
ISL28138, ISL28238
Pin Descriptions
ISL28138
(6 Ld SOT-23)
ISL28138
(8 Ld SOIC)
ISL28238
(8 Ld SOIC)
(8 Ld MSOP)
PIN NAME
1, 5
4
2
2 (A)
6 (B)
FUNCTION
NC
Not connected
ININ-_A
IN-_B
inverting input
EQUIVALENT CIRCUIT
V+
IN-
IN+
VCircuit 1
3
2
3 (A)
5 (B)
IN+
IN+_A
IN+_B
4
V-
3
4
Non-inverting
input
Negative supply
(See circuit 1)
V+
CAPACITIVELY
COUPLED
ESD CLAMP
VCircuit 2
1
6
1 (A)
7 (B)
OUT
OUT_A
OUT_B
Output
V+
OUT
VCircuit 3
6
7
5
8
8
V+
Positive supply
EN
Chip enable
(See circuit 2)
V+
EN
VCircuit 4
Applications Information
Introduction
The ISL28138 and ISL28238 are single and dual channel
CMOS rail-to-rail input, output (RRIO) micropower precision
operational amplifiers. The parts are designed to operate
from single supply (2.4V to 5.5V) or dual supply (±1.2V to
±2.75V). The parts have an input common mode range that
extends 0.25V above the positive rail and 100mV below the
the negative supply rail. The output operation can swing
within about 3mV of the supply rails with a 100kΩ load.
Rail-to-Rail Input
Many rail-to-rail input stages use two differential input pairs,
a long-tail PNP (or PFET) and an NPN (or NFET). Severe
penalties have to be paid for this circuit topology. As the
11
input signal moves from one supply rail to another, the
operational amplifier switches from one input pair to the
other causing drastic changes in input offset voltage and an
undesired change in magnitude and polarity of input offset
current.
The ISL28138 and ISL28238 achieve input rail-to-rail
operation without sacrificing important precision
specifications and degrading distortion performance. The
devices’ input offset voltage exhibits a smooth behavior
throughout the entire common-mode input range. The input
bias current versus the common-mode voltage range gives
us an undistorted behavior from typically 100mV below the
negative rail and 0.25V higher than the V+ rail.
FN6336.2
February 19, 2008
ISL28138, ISL28238
Rail-to-Rail Output
A pair of complementary MOS devices are used to achieve
the rail-to-rail output swing. The NMOS sinks current to
swing the output in the negative direction. The PMOS
sources current to swing the output in the positive direction.
The ISL28138 and ISL28238 with a 100kΩ load will swing to
within 3mV of the positive supply rail and within 3mV of the
negative supply rail.
Results of Over-Driving the Output
Caution should be used when over-driving the output for long
periods of time. Over-driving the output can occur in two ways.
1) The input voltage times the gain of the amplifier exceeds the
supply voltage by a large value or, 2) the output current
required is higher than the output stage can deliver. These
conditions can result in a shift in the Input Offset Voltage (VOS)
as much as 1µV/hr. of exposure under these conditions.
IN+ and IN- Input Protection
All input terminals have internal ESD protection diodes to both
positive and negative supply rails, limiting the input voltage to
within one diode beyond the supply rails. They also contain
back-to-back diodes across the input terminals (see “Pin
Descriptions” on page 11 - Circuit 1). For applications where
the input differential voltage is expected to exceed 0.5V, an
external series resistor must be used to ensure the input
currents never exceed 5mA (Figure 42).
will be enabled by default. When not used, the EN pin should
either be left floating or connected directly to the V- pin.
Limitations of the Differential Input Protection
If the input differential voltage is expected to exceed 0.5V, an
external current limiting resistor must be used to ensure the
input current never exceeds 5mA. For non-inverting unity gain
applications the current limiting can be via a series IN+ resistor,
or via a feedback resistor of appropriate value. For other gain
configurations, the series IN+ resistor is the best choice, unless
the feedback (RF) and gain setting (RG) resistors are both
sufficiently large to limit the input current to 5mA.
Large differential input voltages can arise from several
sources:
1) During open loop (comparator) operation. Used this way,
the IN+ and IN- voltages don’t track, so differentials arise.
2) When the amplifier is disabled but an input signal is still
present. An RL or RG to GND keeps the IN- at GND, while
the varying IN+ signal creates a differential voltage. Mux
Amp applications are similar, except that the active channel
VOUT determines the voltage on the IN- terminal.
3) When the slew rate of the input pulse is considerably
faster than the op amp’s slew rate. If the VOUT can’t keep up
with the IN+ signal, a differential voltage results, and visible
distortion occurs on the input and output signals. To avoid
this issue, keep the input slew rate below 4.8V/µs, or use
appropriate current limiting resistors.
VIN
VOUT
RIN
RL
+
Large (>2V) differential input voltages can also cause an
increase in disabled ICC.
Using Only One Channel
FIGURE 42. INPUT CURRENT LIMITING
Enable/Disable Feature
The ISL28138 offers an EN pin that disables the device
when pulled up to at least 2.0V. In the disabled state (output
in a high impedance state), the part consumes typically 10µA
at room temperature. By disabling the part, multiple
ISL28138 parts can be connected together as a MUX. In this
configuration, the outputs are tied together in parallel and a
channel can be selected by the EN pin. The loading effects
of the feedback resistors of the disabled amplifier must be
considered when multiple amplifier outputs are connected
together. Note that feed through from the IN+ to IN- pins
occurs on any Mux Amp disabled channel where the input
differential voltage exceeds 0.5V (e.g., active channel
VOUT = 1V, while disabled channel VIN = GND), so the mux
implementation is best suited for small signal applications. If
large signals are required, use series IN+ resistors, or large
value RF, to keep the feed through current low enough to
minimize the impact on the active channel. See “Limitations
of the Differential Input Protection” on page 12 for more
details.The EN pin also has an internal pull-down. If left
open, the EN pin will pull to the negative rail and the device
12
If the application only requires one channel of the ISL28238,
the user must configure the unused channel to prevent it
from oscillating. The unused channel 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 channel being used. 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 43).
+
FIGURE 43. PREVENTING OSCILLATIONS IN UNUSED
CHANNELS
FN6336.2
February 19, 2008
ISL28138, ISL28238
Proper Layout Maximizes Performance
Power Dissipation
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 44 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.
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 1:
V+
HIGH IMPEDANCE INPUT
T JMAX = T MAX + ( θ 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 × I SMAX + ( V S - V OUTMAX ) × ---------------------------RL
(EQ. 2)
where:
IN
• TMAX = Maximum ambient temperature
• θJA = Thermal resistance of the package
• PDMAX = Maximum power dissipation of 1 amplifier
FIGURE 44. GUARD RING EXAMPLE FOR UNITY GAIN
AMPLIFIER
• VS = Supply voltage (Magnitude of V+ and V-)
• IMAX = Maximum supply current of 1 amplifier
Current Limiting
The ISL28138 and ISL28238 have 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.
13
• VOUTMAX = Maximum output voltage swing of the
application
• RL = Load resistance
FN6336.2
February 19, 2008
ISL28138, ISL28238
SOT-23 Package Family
MDP0038
e1
D
SOT-23 PACKAGE FAMILY
A
MILLIMETERS
6
N
SYMBOL
4
E1
2
E
3
0.15 C D
1
2X
2
3
0.20 C
5
2X
e
0.20 M C A-B D
B
b
NX
0.15 C A-B
1
3
SOT23-5
SOT23-6
A
1.45
1.45
MAX
A1
0.10
0.10
±0.05
A2
1.14
1.14
±0.15
b
0.40
0.40
±0.05
c
0.14
0.14
±0.06
D
2.90
2.90
Basic
E
2.80
2.80
Basic
E1
1.60
1.60
Basic
e
0.95
0.95
Basic
e1
1.90
1.90
Basic
L
0.45
0.45
±0.10
L1
0.60
0.60
Reference
N
5
6
Reference
D
2X
TOLERANCE
Rev. F 2/07
NOTES:
C
A2
2. Plastic interlead protrusions of 0.25mm maximum per side are not
included.
SEATING
PLANE
A1
0.10 C
1. Plastic or metal protrusions of 0.25mm maximum per side are not
included.
3. This dimension is measured at Datum Plane “H”.
4. Dimensioning and tolerancing per ASME Y14.5M-1994.
NX
5. Index area - Pin #1 I.D. will be located within the indicated zone
(SOT23-6 only).
(L1)
6. SOT23-5 version has no center lead (shown as a dashed line).
H
A
GAUGE
PLANE
c
L
14
0.25
0° +3°
-0°
FN6336.2
February 19, 2008
ISL28138, ISL28238
Small Outline Package Family (SO)
A
D
h X 45°
(N/2)+1
N
A
PIN #1
I.D. MARK
E1
E
c
SEE DETAIL “X”
1
(N/2)
B
L1
0.010 M C A B
e
H
C
A2
GAUGE
PLANE
SEATING
PLANE
A1
0.004 C
0.010 M C A B
L
b
0.010
4° ±4°
DETAIL X
MDP0027
SMALL OUTLINE PACKAGE FAMILY (SO)
INCHES
SYMBOL
SO-14
SO16 (0.300”)
(SOL-16)
SO20
(SOL-20)
SO24
(SOL-24)
SO28
(SOL-28)
TOLERANCE
NOTES
A
0.068
0.068
0.068
0.104
0.104
0.104
0.104
MAX
-
A1
0.006
0.006
0.006
0.007
0.007
0.007
0.007
±0.003
-
A2
0.057
0.057
0.057
0.092
0.092
0.092
0.092
±0.002
-
b
0.017
0.017
0.017
0.017
0.017
0.017
0.017
±0.003
-
c
0.009
0.009
0.009
0.011
0.011
0.011
0.011
±0.001
-
D
0.193
0.341
0.390
0.406
0.504
0.606
0.704
±0.004
1, 3
E
0.236
0.236
0.236
0.406
0.406
0.406
0.406
±0.008
-
E1
0.154
0.154
0.154
0.295
0.295
0.295
0.295
±0.004
2, 3
e
0.050
0.050
0.050
0.050
0.050
0.050
0.050
Basic
-
L
0.025
0.025
0.025
0.030
0.030
0.030
0.030
±0.009
-
L1
0.041
0.041
0.041
0.056
0.056
0.056
0.056
Basic
-
h
0.013
0.013
0.013
0.020
0.020
0.020
0.020
Reference
-
16
20
24
28
Reference
-
N
SO-8
SO16
(0.150”)
8
14
16
Rev. M 2/07
NOTES:
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
15
FN6336.2
February 19, 2008
ISL28138, ISL28238
Mini SO Package Family (MSOP)
0.25 M C A B
D
MINI SO PACKAGE FAMILY
(N/2)+1
N
E
MDP0043
A
E1
MILLIMETERS
PIN #1
I.D.
1
B
(N/2)
e
H
C
SEATING
PLANE
0.10 C
N LEADS
SYMBOL
MSOP8
MSOP10
TOLERANCE
NOTES
A
1.10
1.10
Max.
-
A1
0.10
0.10
±0.05
-
A2
0.86
0.86
±0.09
-
b
0.33
0.23
+0.07/-0.08
-
c
0.18
0.18
±0.05
-
D
3.00
3.00
±0.10
1, 3
E
4.90
4.90
±0.15
-
E1
3.00
3.00
±0.10
2, 3
e
0.65
0.50
Basic
-
L
0.55
0.55
±0.15
-
L1
0.95
0.95
Basic
-
N
8
10
Reference
-
0.08 M C A B
b
Rev. D 2/07
NOTES:
1. Plastic or metal protrusions of 0.15mm maximum per side are not
included.
L1
2. Plastic interlead protrusions of 0.25mm maximum per side are
not included.
A
3. Dimensions “D” and “E1” are measured at Datum Plane “H”.
4. Dimensioning and tolerancing per ASME Y14.5M-1994.
c
SEE DETAIL "X"
A2
GAUGE
PLANE
A1
L
0.25
3° ±3°
DETAIL X
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16
FN6336.2
February 19, 2008