Datasheet

4
LT1959
TYPICAL PERFORMANCE CHARACTERISTICS
UW
Feedback Pin Voltage
Switch Peak Current Limit
Lockout and Shutdown
ThresholdsShutdown Pin Bias Current
Shutdown Supply Current
Shutdown Supply Current
Error Amplifier Transconductance
Error Amplifier Transconductance
Minimum Input Voltage
with 3.3V Output
LOAD CURRENT (mA)
1
4.1
INPUT VOLTAGE (V)
4.3
4.5
4.7
10 100 1000
1959 G01
3.9
3.7
3.5
3.3
DUTY CYCLE (%)
0
SWITCH PEAK CURRENT (A)
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
80
1959 G02
20
40
60
100
TYPICAL
MINIMUM
TEMPERATURE (°C)
–50
1.215
1.210
1.205
100
1959 G03
–25 0 25 50 75 125
FEEDBACK VOLTAGE (V)
TEMPERATURE (°C)
–50
–500
–400
–300
–200
–8
–4
0
25 75
1959 G04
–25 0
50 100 125
CURRENT (µA)
AT 0.37V SHUTDOWN THRESHOLD.
AFTER SHUTDOWN, CURRENT
DROPS TO A FEW µA
AT 2.38V LOCKOUT THRESHOLD
JUNCTION TEMPERATURE (°C)
–50
2.40
2.36
2.32
0.8
0.4
0
25 75
1959 G05
–25 0
50 100 125
SHUTDOWN PIN VOLTAGE (V)
LOCKOUT
START-UP
SHUTDOWN
INPUT VOLTAGE (V)
0
INPUT SUPPLY CURRENT (µA)
25
20
15
10
5
0
51015
1959 G06
V
SHDN
= 0V
FREQUENCY (Hz)
GAIN (µMho)
PHASE (DEG)
3000
2500
2000
1500
1000
500
200
150
100
50
0
–50
100 10k 100k 10M
1959 G09
1k 1M
GAIN
PHASE
ERROR AMPLIFIER EQUIVALENT CIRCUIT
R
OUT
200k
C
OUT
12pF
V
C
R
LOAD
= 50Ω
V
FB
2 × 10
–3
)(
JUNCTION TEMPERATURE (°C)
–50
TRANSCONDUCTANCE (µMho)
2500
2000
1500
1000
500
0
0
50
75
1959 G08
–25
25
100
125
SHUTDOWN VOLTAGE (V)
0
INPUT SUPPLY CURRENT (µA)
70
60
50
40
30
20
10
0
0.1 0.2 0.3 0.4
1959 G07
V
IN
= 10V