LT1055/LT1056
9
10556fd
For more information www.linear.com/LT1055
Supply Current vs Supply Voltage Output Swing vs Load Resistance Short-Circuit Current vs Time
TYPICAL PERFORMANCE CHARACTERISTICS
APPLICATIONS INFORMATION
The LT1055/LT1056 may be inserted directly into LF155A/
LT355A, LF156A/LT356A, OP-15 and OP-16 sockets.
Offset nulling will be compatible with these devices with
the wiper of the potentiometer tied to the positive supply.
Offset Nulling
example, leakage currents in circuitry external to the op
amp can significantly degrade performance. High quality
insulation should be used (e.g. Teflon, Kel-F); cleaning of
all insulating surfaces to remove fluxes and other resi
-
dues will probably be required. Surface coating may be
necessary to provide a moisture barrier in high humidity
environments.
Board leakage can be minimized by encir
cling the input
circuitry with a guard ring operated at a potential close to
that of the inputs: in inverting configurations the guard ring
should be tied to ground, in noninverting connnections
to the inverting input at pin 2. Guarding both sides of the
–
+
V
–
2
3
4
1
5
7
R
P
6
LT1055
LT1056
OFFSET
TRIM
TRIM
GUARD
OUTPUT
INPUTS
V
+
V
–
1
8
7
6
5
4
3
2
No appreciable change in offset voltage drift with tem-
perature will occur when the device is nulled with a
potentiometer, R
P
, ranging from 10k to 200k.
The LT1055/LT1056 can also be used in LF351, LF411,
AD547, AD611, OPA-111, and TL081 sockets, provided
that the nulling cicuitry is removed. Because of the LT1055/
LT1056’s low offset voltage, nulling will not be necessary
in most applications.
Achieving Picoampere/Microvolt Performance
In order to realize the picoampere-microvolt level accuracy
of the LT1055/LT1056 proper care must be exercised. For
SUPPLY VOLTAGE (V)
0
4
6
2
2
0
5
10
15
T
A
= –55°C
T
A
= 125°C
T
A
= –55°C
T
A
= 125°C
LT1056
LT1055
25°C
25°C
LOAD RESISTANCE (kΩ)
0.1 0.3
–15
–9
–12
–3
–6
3
0
9
6
1 3 10
12
T
A
= –25°C
T
A
= –125°C
T
A
= –55°C
T
A
= –55°C
T
A
= –25°C
T
A
= –125°C
V
S
= ±15V
TIME FROM OUTPUT SHORT TO GROUND
(MINUTES)
0
–50
SHORT-CIRCUIT CURRENT (mA)
–40
–20
–10
0
20
1
2
–30
30
40
10
3
T
A
= –55°C
T
A
= 25°C
T
A
= 125°C
T
A
= 125°C
T
A
= 25°C
T
A
= –55°C
SINKING
V
S
= ±15V
