LT1218CS8 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LT1218CS8' PDF : 16 Pages View PDF
LT1218/LT1219
APPLICATIONS INFORMATION
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 200mVP-P 50kHz square wave added to the
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.
V+
V+
(AC)
(AC)
VOUT
LT1218/19 • F07a
Figure 7a. LT1218 Power Supply Rejection Test
VOUT
LT1218/19 • F07b
Figure 7b. LT1219 Power Supply Rejection Test
TYPICAL APPLICATIONS
VIN +
LT1219
–
Buffer for 12-Bit A/D Converter
3V
0.1µF
1µF
0.1µF
1
VREF
8
VCC
2
+ IN
7
CLK
3
LTC1285
6
– IN
DOUT
4
5
GND CS/SHDN
LT1218/19 • TA03
TO µP
LT1004-1.2
High-Side Current Source
VCC
RSENSE
0.2Ω
1k
–
RP LT1218
10k +
0.0033µF
100Ω
Q1
MTP23P06
ILOAD
40k
Q2
2N4340
5V < VCC < 30V
0A < ILOAD < 1A AT VCC = 5V
0mA < ILOAD < 160mA AT VCC = 30V
LT1218/19 • TA04
14
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