LT1766 Linear Technology, LT1766 Datasheet - Page 4

• Manufacturer Part Number: LT1766
• Description: 5.5V to 60V 1.5A/ 200kHz Step-Down Switching Regulator
• Manufacturer: Linear Technology

LT1766/LT1766-5
TYPICAL PERFOR A CE CHARACTERISTICS
4
2.5
2.0
1.5
1.0
2.4
2.0
1.6
1.2
0.8
0.4
2500
2000
1500
1000
500
0
–50
0
Switch Peak Current Limit
0
Lockout and Shutdown
Thresholds
T
–50
A
Error Amplifier Transconductance
= 25 C
–25
–25
JUNCTION TEMPERATURE ( C)
20
JUNCTION TEMPERATURE ( C)
GUARANTEED MINIMUM
0
DUTY CYCLE (%)
0
40
TYPICAL
LOCKOUT
START-UP
SHUTDOWN
25
25
50
60
50
75
75
W
80
100
100
1766 G01
1766 G04
1766 G07
U
100
125
125
1.234
1.229
1.214
1.204
1.224
1.219
1.209
3000
2500
2000
1500
1000
500
–50
100
40
35
30
25
20
15
10
Error Amplifier Transconductance
FB Pin Voltage and Current
5
0
T
ERROR AMPLIFIER EQUIVALENT CIRCUIT
A
V
R
0
Shutdown Supply Current
FB 2 • 10
= 25 C
LOAD
–25
V
T
A
SHDN
= 25 C
JUNCTION TEMPERATURE ( C)
1k
= 50
10
–3
= 0V
0
GAIN
FREQUENCY (Hz)
INPUT VOLTAGE (V)
PHASE
10k
20
25
CURRENT
VOLTAGE
R
200k
50
30
OUT
100k
75
40
1M
C
12pF
100
OUT
V
1766 G02
50
1766 G08
C
1766 G05
10M
125
200
150
100
50
0
–50
2.0
1.5
1.0
0.5
0
60
250
200
150
100
300
250
200
150
100
50
100
12
600
500
400
300
200
6
0
0
–50
0
SHDN Pin Bias Current
0
Shutdown Supply Current
T
0
Frequency Foldback
CURRENT REQUIRED TO FORCE SHUTDOWN
(FLOWS OUT OF PIN). AFTER SHUTDOWN,
CURRENT DROPS TO A FEW A
A
T
A
= 25 C
–25
= 25 C
AT 2.38V STANDBY THRESHOLD
(CURRENT FLOWS OUT OF PIN)
0.1
JUNCTION TEMPERATURE ( C)
SHUTDOWN VOLTAGE (V)
V
0
IN
0.5
= 60V
0.2
25
V
FB
50
V
(V)
0.3
IN
= 15V
1.0
75
FREQUENCY
SWITCHING
CURRENT
0.4
FB PIN
100
1766 G03
1766 G06
1766 G09
1766fa
125
0.5
1.5