LT1637 Linear Technology, LT1637 Datasheet - Page 8

• Manufacturer Part Number: LT1637
• Description: 1.1MHz/ 0.4V/us Over-The-Top Micropower/ Rail-To-Rail Input and Output Op Amp
• Manufacturer: Linear Technology

LT1637
APPLICATIO S I FOR ATIO
Supply Voltage
The positive supply pin of the LT1637 should be bypassed
with a small capacitor (about 0.01 F) within an inch of the
pin. When driving heavy loads an additional 4.7 F electro-
lytic capacitor should be used. When using split supplies,
the same is true for the negative supply pin.
The LT1637 is protected against reverse battery voltages
up to 25V. In the event a reverse battery condition occurs,
the supply current is typically less than 1nA.
When operating the LT1637 on total supplies of 30V or
more, the supply must not be brought up faster than 1 s.
This is especially true if low ESR bypass capacitors are
used. A series RLC circuit is formed from the supply lead
inductance and the bypass capacitor. 5 of resistance in
the supply or the bypass capacitor will dampen the tuned
circuit enough to limit the rise time.
8
TYPICAL PERFOR A CE CHARACTERISTICS
Open-Loop Gain
A: R
B: R
C: R
L
L
L
B
= 2k
= 10k
= 50k
0.0001
0.001
OUTPUT VOLTAGE (5V/DIV)
0.01
–10V
0.1
C
1
100
A
Total Harmonic Distortion + Noise
vs Load Resistance
LOAD RESISTANCE TO GROUND ( )
0V
V
V
U
S
IN
V
V
V
V
= 1.5V
= 0.9V
S
IN
S
IN
= 3V, 0V
= 3V, 0V
A
= 0.3V TO 2.1V
= 0.6V TO 2.4V
B
10V
1k
C
U
V
W
S
= 15V
V
A
V
1637 G24
S
V
IN
= 3V TOTAL
= 1
= 1.8V
U
10k
W
P-P
AT 1kHz
– 10V
1637 G22
10V
100k
Large-Signal Response
U
V
A
S
V
= 15V
= – 1
Inputs
The LT1637 has two input stages, NPN and PNP (see the
Simplified Schematic), resulting in three distinct operat-
ing regions as shown in the Input Bias Current vs Common
Mode typical performance curve.
For input voltages about 0.9V or more below V
input stage is active and the input bias current is typically
– 20nA. When the input voltage is about 0.5V or less from
V
current is typically 80nA. Increases in temperature will
cause the voltage at which operation switches from the
PNP stage to the NPN stage to move towards V
offset voltage of the NPN stage is untrimmed and is
typically 600 V.
+
, the NPN input stage is operating and the input bias
0.001
1637 G25
0.01
0.1
10
1
0
Total Harmonic Distortion + Noise
vs Output Voltage
R
V
f = 1kHz
FOR A
A
V
L
CM
V
S
= 10k
= 1
= 3V, 0V
= HALF SUPPLY
V
= –1, R
OUTPUT VOLTAGE (V
– 50mV
50mV
A
V
V
S
1
G
= 1
= 1.5V
= 100k
Small-Signal Response
V
A
S
V
A
= 15V
= 1
A
V
V
V
S
= –1, V
= –1
= 1.5V
2
P-P
A
V
S
V
S
)
= 3V, 0V
= 1
= 3V, 0V
1637 G23
3
+
+
. The input
, the PNP
1637 G26