lt1959cs8-trpbf Linear Technology Corporation, lt1959cs8-trpbf Datasheet - Page 4

• Manufacturer Part Number: lt1959cs8-trpbf
• Description: 4.5a, 500khz Step-down Switching Regulator
• Manufacturer: Linear Technology Corporation

LT1959
TYPICAL PERFORMANCE CHARACTERISTICS
4
– 400
– 300
– 200
–500
4.7
4.5
4.3
4.1
3.9
3.7
3.5
3.3
– 8
– 4
70
60
50
40
30
20
10
0
0
–50
0
1
Shutdown Supply Current
Minimum Input Voltage
with 3.3V Output
Shutdown Pin Bias Current
V
IN
–25
= 10V
AT 0.37V SHUTDOWN THRESHOLD.
AT 2.38V LOCKOUT THRESHOLD
AFTER SHUTDOWN, CURRENT
0.1
SHUTDOWN VOLTAGE (V)
LOAD CURRENT (mA)
DROPS TO A FEW A
0
TEMPERATURE ( C)
10
25
0.2
50
100
75
0.3
W
100
1959 G01
1959 G04
1959 G07
1000
U
125
0.4
2500
2000
1500
1000
500
2.40
2.36
2.32
0
0.8
0.4
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
–50
0
Error Amplifier Transconductance
–50
0
Switch Peak Current Limit
Lockout and Shutdown
Thresholds
–25
–25
JUNCTION TEMPERATURE ( C)
20
JUNCTION TEMPERATURE ( C)
0
0
MINIMUM
DUTY CYCLE (%)
SHUTDOWN
25
40
25
START-UP
50
50
LOCKOUT
60
75
75
TYPICAL
100
80
100
1959 G08
1959 G05
1959 G02
125
125
100
3000
2500
2000
1500
1000
500
100
1.215
1.210
1.205
Error Amplifier Transconductance
25
20
15
10
ERROR AMPLIFIER EQUIVALENT CIRCUIT
V
R
5
0
– 50
FB 2 10
LOAD
0
Feedback Pin Voltage
Shutdown Supply Current
V
1k
SHDN
= 50
–25
–3
GAIN
= 0V
FREQUENCY (Hz)
PHASE
10k
0
INPUT VOLTAGE (V)
TEMPERATURE ( C)
5
25
R
200k
OUT
100k
50
10
1M
C
12pF
75
OUT
V
1959 G09
C
100
10M
1959 G03
1959 G06
200
150
100
50
0
–50
125
15