Datasheet

LT1175
7
1175ff
TYPICAL PERFORMANCE CHARACTERISTICS
GND Pin Current Ripple Rejection
Shutdown Input Current Shutdown Thresholds SHDN Pin Characteristics
INPUT VOLTAGE (V)
0
INPUT CURRENT (μA)
25
20
15
10
5
0
20
1175 G07
5
10
15
25
T
J
= 125°C
T
J
= –55°C
T
J
= 25°C
TEMPERATURE (°C)
–50
THRESHOLD (V)
2.5
2.0
1.5
1.0
0.5
0
0
5025
75
1175 G08
–25
100
125
POSITIVE THRESHOLD
NEGATIVE THRESHOLD
DEVICE IS OFF
BELOW THRESHOLD
SHUTDOWN TO GROUND VOLTAGE (V)
–25 –20 –10 0
PIN CURRENT (μA)
15
10
5
0
–5
–10
15
1175 G09
–15
–5 10 20
5
25
V
IN
= 25V
CHARACTERISTICS DO NOT
CHANGE SIGNIFICANTLY WITH
TEMPERATURE, SO A SINGLE
CURVE IS SHOWN. POSITIVE
CURRENT FLOWS INTO
SHDN PIN
IF SHDN PIN IS NEGATIVE WITH
RESPECT TO INPUT VOLTAGE AND
INPUT VOLTAGE IS LESS THAN 15V,
NEGATIVE BREAKOVER POINT WILL
BE ABOUT 8V BELOW –V
IN
OUTPUT CURRENT (A)
0
GROUND PIN CURRENT (mA)
20
16
12
8
4
0
0.2
0.40.3
0.5
1175 G10
0.1
0.6
0.7
POWER
TRANSISTOR
IN DROPOUT
T
J
= –55°C
T
J
= 25°C
V
IN
– V
OUT
≥ 3V
T
J
= 25°C
V
IN
– V
OUT
= 2V
T
J
= 25°C
FREQUENCY (Hz)
REJECTION (dB)
100
80
60
40
20
0
10 1k 10k 1M100
100k
V
OUT
= 12V
(ADJUSTABLE)
I
OUT
= 100mA
V
IN
– V
OUT
= 2V
C
OUT
= 1μF TANT
1175 G11
RIPPLE REJECTION IS RELATIVELY INDEPENDENT OF
INPUT VOLTAGE AND LOAD FOR CURRENTS BETWEEN
25mA AND 500mA. LARGER OUTPUT CAPACITORS DO
NOT IMPROVE REJECTION FOR FREQUENCIES BELOW
50kHz. AT VERY LIGHT LOADS, REJECTION WILL
IMPROVE WITH LARGER OUTPUT CAPACITORS
V
OUT
= 12V
(ADJUSTABLE)
WITH 0.1μF ACROSS
DIVIDER RESISTOR
V
OUT
= 5V
(FIXED)