LT1375/LT1376
U W
TYPICAL PERFORMANCE CHARACTERISTICS
Standby and Shutdown Thresholds
Shutdown Pin Bias Current
Shutdown Supply Current
30
25
20
15
10
5
500
400
300
200
8
2.40
2.36
2.32
0.8
0.4
0
V
= 0V
SHUTDOWN
CURRENT REQUIRED TO FORCE SHUTDOWN
(FLOWS OUT OF PIN). AFTER SHUTDOWN,
CURRENT DROPS TO A FEW µA
STANDBY
START-UP
AT 2.38V STANDBY THRESHOLD
(CURRENT FLOWS OUT OF PIN)
4
SHUTDOWN
0
0
50
TEMPERATURE (°C)
100 125
–50 –25
0
25
50
75
100 125
0
5
10
15
20
25
–50 –25
0
25
75
INPUT VOLTAGE (V)
JUNCTION TEMPERATURE (°C)
1375/76 G04
1375/76 G05
1375/76 G06
Shutdown Supply Current
Error Amplifier Transconductance
Error Amplifier Transconductance
2500
2000
1500
1000
500
150
125
100
75
3000
2500
2000
1500
1000
500
200
PHASE
GAIN
150
100
50
V
= 25V
IN
V
C
C
OUT
12pF
R
OUT
200k
–3
V
FB
2 •10
(
)
V
= 10V
50
IN
ERROR AMPLIFIER EQUIVALENT CIRCUIT
= 50Ω
0
25
R
LOAD
0
–50
0
–50
0
25
50
75 100 125
100
1k
10k
100k
1M
10M
0
0.1
0.2
0.3
0.4
0.5
–25
SHUTDOWN VOLTAGE (V)
JUNCTION TEMPERATURE (°C)
FREQUENCY (Hz)
1375/76 G03
1375/76 G07
1375/76 G02
LT1376 Minimum Input Voltage
with 5V Output
Frequency Foldback
Switching Frequency
500
400
300
200
100
0
600
550
500
450
400
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
MINIMUM INPUT VOLTAGE CAN BE
REDUCED BY ADDING A SMALL EXTERNAL
PNP. SEE APPLICATIONS INFORMATION
SWITCHING
FREQUENCY
MINIMUM
VOLTAGE TO
START WITH
STANDARD
CIRCUIT
MINIMUM VOLTAGE
TO RUN WITH
STANDARD CIRCUIT
FEEDBACK PIN
CURRENT
0
0.5
1.0
1.5
2.0
2.5
–25
0
25
50
75
125
–50
100
0
10
100
1000
FEEDBACK PIN VOLTAGE (V)
JUNCTION TEMPERATURE (°C)
LOAD CURRENT (mA)
1375/76 G10
1375/76 G11
1375/76 G12
13756fd
5
Linear [ Linear ]
