ca3420a Intersil Corporation, ca3420a Datasheet - Page 3

• Manufacturer Part Number: ca3420a
• Description: 0.5mhz, Low Supply Voltage, Low Input Current Bimos Operational Amplifiers
• Manufacturer: Intersil Corporation

Electrical Specifications
NOTE:
Typical Applications
Picoammeter Circuit
The exceptionally low input current (typically 0.2pA) makes
the CA3420 highly suited for use in a picoammeter circuit.
With only a single 10G resistor, this circuit covers 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 1M resistor in series
with the input. Higher current ranges require that this resistor
be reduced. The 10M resistor connected to pin 2 of the
CA3420 decouples the potentially high input capacitance
often associated with lower current circuits and reduces the
tendency for the circuit to oscillate under these conditions.
High Input Resistance Voltmeter
Advantage is taken of the high input impedance of the CA3420
in a high input resistance DC voltmeter. Only two 1.5V “AA”
type penlite batteries power this exceedingly high-input
resistance (>1,000,000M ) DC voltmeter. Full-scale deflection
is 500mV, 150mV, and 15mV. Higher voltage 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 300 A. At full-scale deflection this current
rises to 800 A. Carbon-zinc battery life should be in excess
of 1,000 hours.
Input Offset Voltage
Input Offset Current (Note 4)
Input Current (Note 4)
Large Signal Voltage Gain
Common Mode Rejection Ratio
Common Mode Input Voltage Range
Power Supply Rejection Ratio
Max Output Voltage
Supply Current
Device Dissipation
Input Offset Voltage Temperature Drift
4. The maximum limit represents the levels obtainable on high speed automatic test equipment. Typical values are obtained under laboratory conditions.
PARAMETER
3
For Equipment Design, at V
SYMBOL
V
PSRR
CMRR
V
V
V
V
|V
A
|I
lCR
OM
OM
|I
P
lCR
I+
lO
OL
IO
IO
I
D
|
/ T
|
|
+
+
-
-
R
R
CONDITIONS
V
L
L
CA3420, CA3420A
IO
= 10k
=
TEST
/ V
SUPPLY
= 10V, T
MIN
-9.7
-10
8.5
9.7
10
80
70
70
-
-
-
-
-
-
-
-
A
1M
22M
= 25
CA3420
FIGURE 2. HIGH INPUT RESISTANCE VOLTMETER
-10.3
-9.85
TYP
0.03
0.05
100
100
100
450
9.3
9.9
32
80
90
o
9
5
4
C, Unless Otherwise Specified
10G
10M
10M
100pF
FIGURE 1. PICOAMMETER CIRCUIT
MAX
1000
320
320
10pF
10k
10
14
10k
5
3
2
-
-
-
-
-
-
-
-
-
2
3
4
CA3420
+
CA3420
1
+
-
1
-
5
5
MIN
-9.7
9.0
9.7
-10
20
86
70
70
-
-
-
-
-
-
-
-
4
7
4
7
-1.5V
RETURNS
RETURNS
BATTERY
-1.5V
+1.5V
BATTERY
+1.5V
6
CA3420A
6
-10.3
-9.85
TYP
0.03
0.05
100
100
100
450
9.3
9.9
80
32
90
9
2
4
500-0-500
500-0-500
500mV
150mV
1.5pA
15pA
15mV
1.1k
50pA
M
5pA
11k
50mV
A
M
A
MAX
1000
320
320
14
5
4
5
-
-
-
-
-
-
-
-
-
1.5k , 1%
430 , 1%
150 , 1%
1.5k , 1%
430 , 1%
150 , 1%
1.5k
1.5k
68
1%
68
1%
1k
UNITS
1k
kV/V
V/
mW
mV
pA
pA
dB
V/V
dB
V/V
dB
V
V
V
V
A
o
C