Datasheet

LT1766/LT1766-5
6
1766fc
DUTY CYCLE (%)
1.0
SWITCH PEAK CURRENT (A)
1.5
2.0
2.5
20 40
TYPICAL
60 80
1766 G01
1000
GUARANTEED MINIMUM
T
A
= 25°C
JUNCTION TEMPERATURE (°C)
–50
FEEDBACK VOLTAGE (V)
CURRENT (μA)
1.224
1.229
1.234
25 75
1766 G02
1.219
1.214
–25 0
50 100 125 150
1.209
1.204
1.5
2.0
1.0
0.5
0
VOLTAGE
CURRENT
JUNCTION TEMPERATURE (°C)
–50
250
200
150
100
12
6
0
25 75
1766 G03
–25 0
50 100 150125
CURRENT (μA)
CURRENT REQUIRED TO FORCE SHUTDOWN
(FLOWS OUT OF PIN). AFTER SHUTDOWN,
CURRENT DROPS TO A FEW μA
AT 2.38V STANDBY THRESHOLD
(CURRENT FLOWS OUT OF PIN)
TYPICAL PERFORMANCE CHARACTERISTICS
Switch Peak Current Limit SHDN Pin Bias Current
Shutdown Supply Current
Lockout and Shutdown
Thresholds Shutdown Supply Current
Error Amplifi er Transconductance
FB Pin Voltage and Current
Error Amplifi er Transconductance
JUNCTION TEMPERATURE (°C)
–50
SHDN PIN VOLTAGE (V)
50 100
1766 G04
0
25 75
2.4
2.0
1.6
1.2
0.8
0.4
0
–25 150125
LOCKOUT
START-UP
SHUTDOWN
INPUT VOLTAGE (V)
0
INPUT SUPPLY CURRENT (μA)
1766 G05
10 20 30 40 50 60
40
35
30
25
20
15
10
5
0
V
SHDN
= 0V
T
A
= 25°C
SHUTDOWN VOLTAGE (V)
0
0
INPUT SUPPLY CURRENT (μA)
50
100
150
200
250
300
0.1 0.2 0.3 0.4
1766 G06
0.5
V
IN
= 60V
V
IN
= 15V
T
A
= 25°C
JUNCTION TEMPERATURE (°C)
TRANSCONDUCTANCE (μmho)
1766 G07
2500
2000
1500
1000
500
0
–50
50 100
0
25 75–25 150125
FREQUENCY (Hz)
GAIN (μMho)
PHASE (DEG)
3000
2500
2000
1500
1000
500
200
150
100
50
0
–50
100 10k 100k 10M
1766 G08
1k 1M
GAIN
PHASE
ERROR AMPLIFIER EQUIVALENT CIRCUIT
R
OUT
200k
C
OUT
12pF
V
C
R
LOAD
= 50Ω
V
FB
2 • 10
–3
)(
T
A
= 25°C
V
FB
(V)
0
SWITICHING FREQUENCY (kHz)
OR FB CURRENT (μA)
300
400
600
500
1766 G09
200
100
0
0.5
1.0
1.5
SWITCHING
FREQUENCY
FB PIN
CURRENT
T
A
= 25°C
Frequency Foldback