Linear Technology DC2177A-C Demo Manual

DESCRIPTION
Demonstration circuit 2177A-C features the
micropower, low noise and low dropout voltage linear
regulator with output discharge. The input voltage ranges
from 2.1V to 45V and the maximum output current is
200mA. A resistor divider determines the output voltage,
and a jumper adjusts the divider to set the output voltage
to either 1.2V, 1.5V, 1.8V, 2V, 2.5V, 3.3V, 5V or a voltage
that is user-programmed but requires the installation of
a resistor. The output uses a 10µF ceramic capacitor and
the internal reference is bypassed with a 10nF capacitor
to reduce output noise and program the soft-start. There
is also a 10nF feedforward capacitor to improve load
transient response and decrease noise at higher output
voltages. The position of the VOUTEN jumper either pulls
up the SHDN pin to the input supply through a 100k re-
sistor, shorts SHDN to ground or floats the SHDN pin so
it can be driven directly by a signal applied to the SHDN
terminal. The input supply to the LT3063 is bypassed by a
2.2µF ceramic capacitor and there is also a 50V tantalum
polymer capacitor on the input to dampen ringing that
may occur when the input is hot-plugged using long leads.
PERFORMANCE SUMMARY
PARAMETER
Minimum Input Voltage, V
Maximum Input Voltage, V
Output Voltage, V
OUT
Maximum Output Current, I
Output Discharge Time
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CONDITIONS
V – V
IN IN OUT
IN
V SELECT = 1.2V
OUT
V SELECT = 1.5V
OUT
V SELECT = 1.8V
OUT
V SELECT = 2V
OUT
V SELECT = 2.5V
OUT
V SELECT = 3.3V
OUT
V SELECT = 5V
OUT
V = 2.3V, V
OUT IN
V = 2.9V, C
OUT
DEMO MANUAL DC2177A-C
45V VIN, Micropower,
Low Noise, 200mA LDO
with Output Discharge
3063, a The LT3063 saves energy by being micropower and low
®
dropout. The LT3063 has excellent regulation and fast
response to load transients and also tolerates wide input
voltage variations and discharges its output in a controlled
manner as required by some image sensor loads.
The LT3063 targets systems with inputs that are battery-
powered or have multiple sources, especially those with
sensitive loads. DC2177A-C features the LT3063 in the
8-lead 2mm × 3mm DFN package. The LT3063 data sheet
must be read in conjunction with this demo manual to
properly use or modify demo circuit DC2177A-C.
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at T = 25°C
A
≥ 360mV
= 1.8V
OUT
= 10µF
OUT
LT3063
MIN TYP MAX
2.1
45
1.17 1.2 1.23
1.47 1.5 1.54
1.76 1.8 1.85
1.97 2.0 2.07
2.43 2.5 2.56
3.23 3.3 3.41
4.85 5.0 5.13
200
750
UNITS
V
V
V
V
V
V
V
V
V
mA
µs
dc2177acf
1