LT1218L Linear Technology Corporation, LT1218L Datasheet - Page 14

• Manufacturer Part Number: LT1218L
• Description: Precision Rail-to-rail Input And Output Op Amp
• Manufacturer: Linear Technology Corporation

LT1218/LT1219
APPLICATIONS
compensation. The output capacitance forms a filter,
which reduces pickup from the supply and lowers the
output impedance. This additional filtering is helpful in
mixed analog/digital systems with common supplies or
systems employing switching supplies. Filtering also
reduces high frequency noise, which may be beneficial
when driving A/D converters.
Figures 7a and 7b show the outputs of the LT1218/LT1219
perturbed by a 200mV
14
TYPICAL APPLICATIONS
V
IN
+
–
LT1219
Figure 7a. LT1218 Power Supply Rejection Test
V
(AC)
OUT
V
+
Buffer for 12-Bit A/D Converter
U
P-P
0.1 F
0.1 F
INFORMATION
50kHz square wave added to the
U
3V
U
W
1
2
3
4
V
+ IN
– IN
GND
LT1218/19 • F07a
REF
LTC1285
CS/SHDN
D
LT1218/19 • TA03
CLK
V
OUT
U
CC
1 F
8
7
6
5
TO P
positive supply. The LT1219 power supply rejection is
about ten times greater than that of the LT1218 at 50kHz.
Note the 5-to-1 scale change in the output voltage traces.
The tolerance of the external compensation capacitor is
not critical. The plots of Overshoot vs Load Current in the
Typical Performance Characteristics section illustrate the
effect of a capacitive load.
LT1004-1.2
V
Figure 7b. LT1219 Power Supply Rejection Test
(AC)
OUT
V
+
High-Side Current Source
V
CC
Q2
2N4340
40k
R
10k
P
–
+
LT1218
5V < V
0A < I
0mA < I
LOAD
CC
LOAD
< 30V
< 1A AT V
< 160mA AT V
100
0.0033 F
R
LT1218/19 • F07b
0.2
SENSE
1k
I
LOAD
CC
= 5V
CC
LT1218/19 • TA04
= 30V
Q1
MTP23P06