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.
θ
JA
is measured with the component mounted on an evaluation PC board in free air.
Electrical Specifications
PARAMETER
Input Resistance
Input Capacitance
Output Resistance
Equivalent Input Noise Voltage
Short-Circuit Current
To Opposite Supply
Gain Bandwidth Product
Slew Rate
Transient Response
Current from Terminal 8
Typical Values Intended Only for Design Guidance, V
SUPPLY
=
±10V,
T
A
= 25
o
C
SYMBOL
R
I
C
I
R
O
e
N
I
OM
+
I
OM
-
f
T
SR
f = 1kHz
f = 10kHz
R
S
= 100Ω
TEST CONDITIONS
CA3420A
150
4.9
300
62
38
2.6
2.4
0.5
0.5
R
L
= 2kΩ, C
L
= 100pF
0.7
15
20
2
CA3420
150
4.9
300
62
38
2.6
2.4
0.5
0.5
0.7
15
20
2
UNITS
TΩ
pF
Ω
nV/√Hz
nV/√Hz
mA
mA
MHz
V/µs
µs
%
µA
mA
Source
Sink
Rise Time
Overshoot
To V-
To V+
t
R
OS
I
8
+
I
8
-
Electrical Specifications
PARAMETER
Input Offset Voltage
Input Offset Current (Note 3)
Input Current (Note 3)
Large Signal Voltage Gain
Common Mode Rejection Ratio
For Equipment Design, At V
SUPPLY
=
±
1V, T
A
= 25
o
C, Unless Otherwise Specified
SYMBOL
|V
IO
|
|I
IO
|
|I
I
|
A
OL
CMRR
V
lCR
+
V
lCR
-
PSRR
V
OM
+
V
OM
-
I+
P
D
∆V
lO
/∆T
∆V
IO
/∆V
R
L
=
∞
R
L
= 10kΩ
TEST
CONDITIONS
CA3420
MIN
-
-
-
10
80
-
55
0.2
-
-
60
0.90
-0.85
-
-
-
TYP
5
0.01
1
100
100
560
65
0.5
-1.3
100
80
0.95
-0.91
350
0.7
4
MAX
10
4
5
-
-
1800
-
-
-
1000
-
-
-
650
1.1
-
MIN
-
-
-
20
86
-
60
0.2
-1
-
70
0.90
-0.85
-
-
-
CA3420A
TYP
2
0.01
0.02
100
100
560
65
0.5
-1.3
32
90
0.95
-0.91
350
0.7
4
MAX
5
4
5
-
-
1000
-
-
-
320
-
-
-
650
1.1
-
UNITS
mV
pA
pA
kV/V
dB
µV/V
dB
V
V
µV/V
dB
V
V
µA
mW
µV/
o
C
Common Mode Input Voltage Range
Power Supply Rejection Ratio
Max Output Voltage
Supply Current
Device Dissipation
Input Offset Voltage Temperature Drift
NOTE:
3. The maximum limit represents the levels obtainable on high speed automatic test equipment. Typical values are obtained under laboratory conditions.
2
CA3420, CA3420A
Electrical Specifications
PARAMETER
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
NOTE:
4. The maximum limit represents the levels obtainable on high speed automatic test equipment. Typical values are obtained under laboratory conditions.
For Equipment Design, at V
SUPPLY
=
±10V,
T
A
= 25
o
C, Unless Otherwise Specified
SYMBOL
|V
IO
|
|I
IO
|
|I
I
|
A
OL
CMRR
V
lCR
+
V
lCR
-
PSRR
V
OM
+
V
OM
-
I+
P
D
∆V
lO
/∆T
∆V
IO
/∆V
R
L
=
∞
R
L
= 10kΩ
TEST
CONDITIONS
CA3420
MIN
-
-
-
10
80
-
70
8.5
-10
-
70
9.7
-9.7
-
-
-
TYP
5
0.03
0.05
100
100
100
80
9.3
-10.3
32
90
9.9
-9.85
450
9
4
MAX
10
4
5
-
-
320
-
-
-
320
-
-
-
1000
14
-
MIN
-
-
-
20
86
-
70
9.0
-10
-
70
9.7
-9.7
-
-
-
CA3420A
TYP
2
0.03
0.05
100
100
100
80
9.3
-10.3
32
90
9.9
-9.85
450
9
4
MAX
5
4
5
-
-
320
-
-
-
320
-
-
-
1000
14
-
UNITS
mV
pA
pA
kV/V
dB
µV/V
dB
V
V
µV/V
dB
V
V
µA
mW
µV/
o
C
Typical Applications
10GΩ
10pF
+1.5V
2
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 10GΩ 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 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
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.
1MΩ
10MΩ
3
-
CA3420
+
5
1
7
6
4
BATTERY
RETURNS
500-0-500
µA
M
±50pA
±15pA
±5pA
-1.5V
±1.5pA
1.5kΩ
1.5kΩ, 1%
1kΩ
430Ω, 1%
10kΩ
150Ω, 1%
11kΩ
68Ω
1%
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 (>1,000,000MΩ) 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 300µA. At full-scale deflection this current
rises to 800µA. Carbon-zinc battery life should be in excess
of 1,000 hours.
FIGURE 1. PICOAMMETER CIRCUIT
+1.5V
3
22MΩ
10MΩ
100pF
2
+
CA3420
7
6
4
5
1
10kΩ
BATTERY
RETURNS
500-0-500
µA
M
±500mV
1.5kΩ
1.5kΩ, 1%
1kΩ
±50mV
-1.5V
±15mV
150Ω, 1%
430Ω, 1%
-
±150mV
1.1kΩ
68Ω
1%
FIGURE 2. HIGH INPUT RESISTANCE VOLTMETER
3
CA3420, CA3420A
Typical Performance Curves
INPUT & OUTPUT VOLTAGE EXCURSIONS FROM THE
POSITIVE AND NEGATIVE SUPPLY VOLTAGE (V)
1.0
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
0
1
5
10
15
SUPPLY VOLTAGE (V)
V
O
+
V
ICR
-
V
ICR
+
V
O
-
T
A
= 25
o
C
R
L
= 100kΩ
OUTPUT STAGE TRANSISTOR SATURATION
VOLTAGE, Q
19
(mV)
10
T
A
= 25
o
C
V- = 0V
V+ = 2V
V+ = 5V
V+ = 10V
V+ = 20V
100
1000
0.01
0.1
1
10
LOAD (SOURCING) CURRENT (mA)
FIGURE 3. OUTPUT VOLTAGE SWING AND COMMON MODE
INPUT VOLTAGE RANGE vs SUPPLY VOLTAGE
1000
OUTPUT STAGE TRANSISTOR SATURATION
VOLTAGE, Q
17
(mV)
T
A
= 25
o
C
V+ = 0V
FIGURE 4. OUTPUT VOLTAGE vs LOAD SOURCING CURRENT
EQUIVALENT INPUT NOISE VOLTAGE (nV/√Hz)
1000
V
S
=
±10V
V
S
=
±5V
V
S
=
±1V
100
T
A
= 25
o
C
100
V- = -20V
V- = -10V
V- = -5V
V- = -2V
10
10
0.01
0.1
1
10
1
10
1
10
2
10
3
10
4
10
5
10
6
LOAD (SINKING) CURRENT (mA)
FREQUENCY (Hz)
FIGURE 5. OUTPUT VOLTAGE vs LOAD SINKING CURRENT
FIGURE 6. INPUT NOISE VOLTAGE vs FREQUENCY
100
OPEN LOOP VOLTAGE GAIN (dB)
0
-45
-90
80
60
-135
-180
40
20
0
1
10
1
10
2
10
3
10
4
10
5
10
6
FREQUENCY (Hz)
FIGURE 7. OPEN LOOP GAIN AND PHASE SHIFT RESPONSE
4
OPEN LOOP PHASE (DEGREES)
T
A
= 25
o
C
V
S
=
±5V
R
L
= 10kΩ
C
L
= 0pF
CA3420, CA3420A
Dual-In-Line Plastic Packages (PDIP)
N
E1
INDEX
AREA
1 2 3
N/2
E8.3
(JEDEC MS-001-BA ISSUE D)
8 LEAD DUAL-IN-LINE PLASTIC PACKAGE
INCHES
SYMBOL
-B-
MILLIMETERS
MIN
-
0.39
2.93
0.356
1.15
0.204
9.01
0.13
7.62
6.10
MAX
5.33
-
4.95
0.558
1.77
0.355
10.16
-
8.25
7.11
NOTES
4
4
-
-
8, 10
-
5
5
6
5
-
6
7
4
9
Rev. 0 12/93
MIN
-
0.015
0.115
0.014
0.045
0.008
0.355
0.005
0.300
0.240
MAX
0.210
-
0.195
0.022
0.070
0.014
0.400
-
0.325
0.280
-A-
D
BASE
PLANE
SEATING
PLANE
D1
B1
B
0.010 (0.25) M
D1
A
1
A2
L
A
C
L
E
A
A1
A2
B
B1
C
D
D1
E
-C-
e
A
e
C
C
e
C A B S
e
B
NOTES:
1. Controlling Dimensions: INCH. In case of conflict between
English and Metric dimensions, the inch dimensions control.
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Symbols are defined in the “MO Series Symbol List” in Section
2.2 of Publication No. 95.
4. Dimensions A, A1 and L are measured with the package seated
in JEDEC seating plane gauge GS-3.
5. D, D1, and E1 dimensions do not include mold flash or protru-
sions. Mold flash or protrusions shall not exceed 0.010 inch
(0.25mm).
6. E and e
A
are measured with the leads constrained to be per-
pendicular to datum -C- .
7. e
B
and e
C
are measured at the lead tips with the leads uncon-
strained. e
C
must be zero or greater.
8. B1 maximum dimensions do not include dambar protrusions.
Dambar protrusions shall not exceed 0.010 inch (0.25mm).
9. N is the maximum number of terminal positions.
10. Corner leads (1, N, N/2 and N/2 + 1) for E8.3, E16.3, E18.3,
E28.3, E42.6 will have a B1 dimension of 0.030 - 0.045 inch
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