CA5420A
Data Sheet September 1998 File Number 1925.4
0.5MHz, Low Supply Voltage, Low Input
Current BiMOS Operational Amplifiers
The CA5420A is an integrated circuit operational amplifier
that combines PMOS transistors and bipolar transistors on a
single monolithic chip. It is designed and guaranteed to
operate in microprocessor logic systems that use V+ = 5V,
V- = GND, since it can operate down to ±1V supplies. It will
also be suitable for 3.3V logic systems.
The CA5420A BiMOS operational amplifier features gateprotected PMOS transistors in the input circuit to provide
very high inputimpedance,very lowinputcurrents(lessthan
1pA). The internal bootstrapping network features a unique
guardbanding techniquefor reducing the doublingofleakage
current for every 10
CA5420A operates at total supply voltages from 2V to 20V
either single or dual supply. This operational amplifier is
internally phase compensated to achievestableoperationin
the unity gain follower configuration. Additionally, it has
access terminals for a supplementary external capacitor if
additional frequency roll-off is desired. Terminals are also
provided for use in applications requiring input offset voltage
nulling. The use of PMOS in the input stage results in
common-mode input voltage capability down to 0.45V below
the negativesupplyterminal,animportant attribute forsingle
supply application. The output stage uses a feedback OTA
type amplifier that can swing essentially from rail-to-rail. The
output driving current of 1.0mA (Min) is provided by using
nonlinear current mirrors.
This device has guaranteed specifications for 5Voperation
over the full military temperature range of -55
o
C increase in temperature. The
o
C to 125oC.
Features
• CA5420A at 5V Supply Voltage with Full Military
Temperature Range Guaranteed Specifications
• CA5420A Guaranteed to Operate from ±1V to ±10V
Supplies
• 2V Supply at 300µA Supply Current
• 1pA (Typ) Input Current (Essentially Constant to 85
o
• Rail-to-Rail Output Swing (Drive ±2mA Into 1kΩ Load)
• Pin Compatible with 741 Op Amp
Applications
• pH Probe Amplifiers
• Picoammeters
• Electrometer (High Z) Instruments
• Portable Equipment
• Inaccessible Field Equipment
• Battery Dependent Equipment (Medical and Military)
• 5V Logic Systems
• Microprocessor Interface
Ordering Information
PART NUMBER
(BRAND)
CA5420AM
(5420A)
TEMP.
RANGE (oC) PACKAGE
-55 to 125 8 Ld SOIC M8.15
PKG.
NO.
C)
The CA5420A has the same 8 lead pinout used for the
industry standard 741.
Functional Diagram
X1
-
MOS
X1
BUFFER AMPS;
BOOTSTRAPPED
INPUT PROTECTION
NETWORK
BIPOLAR
+
HIGH GAIN
(50K)
1
MOS
BIPOLAR
OTA BUFFER
(X2)
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Pinout
CA5420A
(SOIC)
TOP VIEW
OFFSET
NON-INV.
NOTE: Pin is connected to Case.
1-888-INTERSIL or 321-724-7143
NULL
INV.
INPUT
INPUT
1
2
3
4
V-
8
STROBE
7
-
+
| Copyright © Intersil Corporation 1999
V+
6
OUTPUT
OFFSET
5
NULL
CA5420A
Absolute Maximum Ratings Thermal Information
Supply Voltage (Between V+ and V- Terminals) . . . . . . . . . . . . 22V
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . (V+ + 8V) to (V- -0.5V)
Input Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1mA
Output Short Circuit Duration (Note 1). . . . . . . . . . . . . . . . Indefinite
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . -55oC to 125oC
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.
NOTES:
1. Short circuit may be applied to ground or to either supply.
2. θJA is measured with the component mounted on an evaluation PC board in free air.
Thermal Resistance (Typical, Note 2) θJA (oC/W) θJC (oC/W)
SOIC Package . . . . . . . . . . . . . . . . . . . 157 N/A
Maximum Junction Temperature (Plastic Package) . . . . . . . 150oC
Maximum Storage Temperature Range (All T ypes). . . -65oC to 150oC
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300oC
(SOIC - Lead Tips Only)
Electrical Specifications Typical Values Intended Only for Design Guidance. V+ = +5V; V- = GND, T
= 25oC
A
PARAMETER SYMBOL TEST CONDITIONS CA5420A UNITS
Input Resistance R
Input Capacitance C
Output Resistance R
Equivalent Input
Noise Voltage
Short-Circuit Current To
Opposite Supply
Source IOM+ 2.6 mA
Sink IOM- 2.4 mA
Gain Bandwidth Product f
I
I
O
e
N
f = 1kHz RS = 100Ω 62 nV/√Hz
f = 10kHz 38 nV/√Hz
T
150 TΩ
4.9 pF
300 Ω
0.5 MHz
Slew Rate SR 0.5 V/µs
Transient Response Rise Time t
r
RL = 2kΩ, CL = 100pF 0.7 µs
Overshoot OS 15 %
Current from Terminal 8 To V- I8+20µA
Current from Terminal 8 To V+ I8-2mA
Settling Time 0.01% AV = 1 2V
0.10% AV = 1 2V
Electrical Specifications T
= 25oC, V+ = 5V, V- = 0, Unless Otherwise Specified
A
TEST
PARAMETER SYMBOL
Input Offset Voltage V
Input Offset Current I
Input Current I
IO
IO
I
VO = 2.5V - 1 5 mV
VO = 2.5V - 0.02 0.5 pA
VO = 2.5V - 0.02 1 pA
CONDITIONS
Input 8 µs
P-P
Input 4.5 µs
P-P
CA5420A
UNITSMIN TYP MAX
Common Mode Rejection Ratio CMRR VCM = 0 to 3.7V, VO = 2.5V 75 83 - dB
Common Mode Input Voltage Range V
+VO = 2.5V 3.7 4 - V
lCR
V
- - -0.3 0 V
lCR
Power Supply Rejection Ratio PSRR ∆V+ = 1V; ∆V- = 1V 75 83 - dB
Large Signal Voltage Gain A
OL
VO = 0.5 to 4V RL = ∞ 85 87 - dB
VO = 0.5 to 4V RL = 10kΩ 85 87 - dB
VO = 0.7 to 3V RL = 2kΩ 80 85 - dB
2
CA5420A
Electrical Specifications T
PARAMETER SYMBOL
Source Current I
Sink Current I
= 25oC, V+ = 5V, V- = 0, Unless Otherwise Specified (Continued)
A
TEST
CONDITIONS
SOURCE
SINK
VO = 0V 1.2 2.7 - mA
VO = 5V 1.2 2.1 - mA
CA5420A
UNITSMIN TYP MAX
Output Voltage VOM+RL = ∞ 4.9 4.94 - V
VOM- - 0.13 0.15 V
VOM+RL = 10kΩ 4.7 4.9 - V
VOM- - 0.12 0.15 V
VOM+RL = 2kΩ 3.5 4.6 - V
VOM- - 0.1 0.15 V
Supply Current I
SUPPLY
VO = 0V - 400 500 µA
VO = 2.5V - 430 550 µA
Electrical Specifications T
PARAMETER SYMBOL
Input Offset Voltage V
Input Offset Current I
= -55oC to 125oC, V+ = 5V, V- = 0, Unless Otherwise Specified
A
TEST
CONDITIONS
IO
IO
VO = 2.5V - 2 10 mV
VO = 2.5V - 1.5 3 nA
CA5420A
UNITSMIN TYP MAX
Up to TA = 85oC - 2 10 pA
Input Current |II| VO = 2.5V - 2 5 nA
Up to TA = 85oC -1015pA
Common Mode Rejection Ratio CMRR VCM = 0 to 3.7V,
70 80 - dB
VO = 2.5V
Common Mode Input Voltage Range V
Power Supply Rejection Ratio PSRR ∆V+ = 1V;
+VO = 2.5V 3.7 4 - V
lCR
V
- - -0.3 0 V
lCR
70 83 - dB
∆V- = 1V
Large Signal Voltage Gain A
OL
VO = 0.5 to 4V RL = ∞ 85 87 - dB
VO = 0.7 to 4V RL = 10kΩ 80 87 - dB
VO = 0.7 to 2.5V RL = 2kΩ 75 80 - dB
Source Current I
Sink Current I
SOURCE
SINK
VO = 0V 1 2.7 - mA
VO = 5V 1 2.1 - mA
Output Voltage VOM+RL = ∞ 4.8 4.9 - V
VOM- - 0.16 0.2 V
VOM+RL = 10kΩ 4.7 4.9 - V
VOM- - 0.15 0.2 V
VOM+RL = 2kΩ 34- V
VOM- - 0.14 0.2 V
Supply Current I
SUPPLY
VO = 0V - 430 550 µA
VO = 2.5V - 480 600 µA
3
CA5420A
Electrical Specifications For Equipment Design at V
PARAMETER SYMBOL
Input Offset Voltage V
IO
= ±1V, TA = 25oC, Unless Otherwise Specified
SUPPLY
TEST
CONDITIONS
-2 5 mV
CA5420A
UNITSMIN TYP MAX
Input Offset Current |IIO| - 0.01 4 (Note 3) pA
Input Current |II| - 0.02 5 (Note 3) pA
Large Signal Voltage Gain A
OL
RL = 10kΩ 20 100 - kV/V
86 100 - dB
Common Mode Rejection Ratio CMRR - 560 1000 µV/V
60 65 - dB
Common Mode Input Voltage Range V
+ 0.2 0.5 - V
lCR
V
- -1 -1.3 - V
lCR
Power Supply Rejection Ratio PSRR - 32 320 µV/V
70 90 - dB
Maximum Output Voltage VOM+RL = ∞ 0.9 0.95 - V
VOM- -0.85 -0.91 - V
Supply Current I
SUPPLY
Device Dissipation P
D
- 350 650 µA
- 0.7 1.1 mW
Input Offset Voltage Temp. Drift ∆VIO/∆T-4-µV/oC
Electrical Specifications For Equipment Design at V
PARAMETER SYMBOL
Input Offset Voltage V
IO
= ±10V, TA = 25oC, Unless Otherwise Specified
SUPPLY
TEST
CONDITIONS
-2 5 mV
CA5420A
UNITSMIN TYP MAX
Input Offset Current |IIO| - 0.03 4 (Note 3) pA
Input Current |II| - 0.05 5 (Note 3) pA
Large Signal Voltage Gain A
OL
RL = 10kΩ 20 100 - kV/V
86 100 - dB
Common Mode Rejection Ratio CMRR - 100 320 µV/V
70 80 - dB
Common Mode Input Voltage Range V
+ 9 9.3 - V
lCR
V
- -10 -10.3 - V
lCR
Power Supply Rejection Ratio PSRR - 32 320 µV/V
70 90 - dB
Maximum Output Voltage VOM+RL = ∞ 9.7 9.9 - V
VOM- -9.7 -9.85 - V
Supply Current I
SUPPLY
Device Dissipation P
Input Offset Voltage
∆VIO/∆T-4-µV/oC
D
- 450 1000 µA
- 9 14 mW
Temperature Drift
NOTE:
3. The maximum limitrepresents the levels obtainableon high-speed automatic testequipment. Typical values areobtained under laboratoryconditions.
4
CA5420A
Typical Applications
Picoammeter Circuit
The exceptionally low input current (typically 0.2pA) makes
the CA5420A highly suited for use in a picoammeter circuit.
With only a single 10GΩ resistor, this circuit co vers the range
from ±1.5pA. Higher current ranges are possible with suitable
switching techniques and current scaling resistors. Input
transient protection is provided by the 1MΩ resistor in series
with the input. Higher current ranges require that this resistor
be reduced. The 10MΩ resistor connected to pin 2 of the
CA5420A decouples the potentially high input capacitance
often associated with lower current circuits and reduces the
tendency for the circuit to oscillate under these conditions.
10GΩ
10pF
2
10MΩ1MΩ
3
10kΩ
+1.5V
-
CA5420A
+
5
1
7
6 M
4
BATTERY
RETURNS
-1.5V
500-0-500
µA
±50pA
±15pA
±5pA
±1.5pA
1.5kΩ
1.5kΩ
1%
1kΩ
430Ω
1%
150Ω
1%
High Input Resistance Voltmeter
Advantage is taken of the high input impedance of the
CA5420A in a high input resistance DC voltmeter . Only two
1.5V “AA” type penlite batteries power this exceedingly highinput resistance (>1,000,000MΩ) DC voltmeter. Full-scale
deflection is ±500mV, ±150mV, and ±15mV . Higher v oltage
ranges are easily added with external input voltage attenuator
networks.
The meter is placed in series with the gain network, thus
eliminating the meter temperature coefficient error term.
Supply current in the standby position with the meter
undeflected is 300µA. At full-scale deflection this current
rises to 800µA. Carbon-zinc battery life should be in excess
of 1,000 hours.
+1.5V
500-0-500
6 M
±500mV
±150mV
±50mV
±15mV
µA
1.5kΩ
1.5kΩ
1%
430Ω
1%
150Ω
1%
1kΩ
10MΩ22MΩ
100pF
3
2
10kΩ
+
CA5420A
-
5
1
7
4
BATTERY
RETURNS
-1.5V
68Ω
11kΩ
1%
FIGURE 1. PICOAMMETER CIRCUIT
Typical Performance Curves
1.0
= 25oC
T
A
0.8
RL = 100kΩ
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
POSITIVE AND NEGA TIVE SUPPLY VOLTAGE (V)
INPUT & OUTPUT VOLTAGE EXCURSIONS FROM THE
510
SUPPLY VOLTAGE (V)
FIGURE 3. OUTPUT VOLTAGESWING AND COMMON MODE
INPUT VOLTAGE RANGE vs SUPPLY VOLTAGE
V
-
O
V
+
O
V
-
ICR
V
+
ICR
10
68Ω
1.1kΩ
1%
FIGURE 2. HIGH INPUT RESISTANCE VOLTMETER
10
T
= 25oC
A
V- = 0V
V+ = 2V
V+ = 5V
V+ = 10V
100
V+ = 20V
VOLTAGE, Q19 (mV)
OUTPUT STAGE TRANSISTOR SATURATION
15
1000
LOAD (SOURCING) CURRENT (mA)
1010.10.001
FIGURE 4. OUTPUT VOLTAGE vs LOAD SOURCING CURRENT
5
Typical Performance Curves (Continued)
CA5420A
1000
T
= 25oC
A
V+ = 0V
V+ = 5V
V- = GND
2400
V- = -20V
2000
V- = -10V
100
V- = -5V
1600
V- = -2V
1200
VOLTAGE, Q17 (mV)
800
SUPPLY CURRENT (µA)
400
OUTPUT STAGE TRANSISTOR SATURATION
10
LOAD (SINKING) CURRENT (mA)
1010.10.01
01 2345
OUTPUT VOLTAGE (V)
FIGURE 5. OUTPUT VOLTAGE vs LOAD SINKING CURRENT FIGURE 6. SUPPLY CURRENT vs OUTPUT VOLTAGE
5.00
3.75
2.50
T
= 25oC
A
V+ = 5V
V- = GND
R
TO GND
L
800
700
600
500
400
V+ = 5V
V- = GND
300
1.25
OUTPUT VOLTAGE SWING (V)
0
0 1 10 100 1000
LOAD RESISTANCE (kΩ)
200
INPUT BIAS CURRENT (pA)
100
0
25 35 45 55 65 75 85 95 105 115 125
TEMPERATURE (
o
C)
FIGURE 7. OUTPUT VOLTAGE SWING vs LOAD RESISTANCE FIGURE 8. INPUT BIAS CURRENT DRIFT (∆IB/∆T)
EQUIVALENT INPUT NOISE VOLTAGE (nV√Hz)
1000
100
10
VS = ±10V
V
= ±5V
S
V
= ±1V
S
TA = 25oC
100
80
60
1
1
1
10
2
10
3
10
4
10
5
10
6
10
FREQUENCY (Hz)
40
20
OPEN LOOP VOLTAGE GAIN (dB)
0
10
110
2
1
10
FREQUENCY (Hz)
T
= 25oC
A
V+ = +10V, V- = 10V
R
= 10kΩ
L
= 0pF
C
L
4
3
10
6
5
10
10
0
-45
-90
-135
-180
OPEN LOOP PHASE (DEGREES)
FIGURE 9. INPUT NOISE VOLTAGE vs FREQUENCY FIGURE 10. OPEN LOOP GAIN AND PHASE SHIFT RESPONSE
6
CA5420A
All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification.
Intersil semiconductor products are sold by description only.Intersil Corporation reserves the right to make changes in circuit design 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 web site www.intersil.com
Sales Office Headquarters
NORTH AMERICA
Intersil Corporation
P. O. Box 883, Mail Stop 53-204
Melbourne, FL 32902
TEL: (321) 724-7000
FAX: (321) 724-7240
7
EUROPE
Intersil SA
Mercure Center
100, Rue de la Fusee
1130 Brussels, Belgium
TEL: (32) 2.724.2111
FAX: (32) 2.724.22.05
ASIA
Intersil (Taiwan) Ltd.
7F-6, No. 101 Fu Hsing North Road
Taipei, Taiwan
Republic of China
TEL: (886) 2 2716 9310
FAX: (886) 2 2715 3029
Loading...