Datasheet

LT1952/LT1952-1
3
19521fe
PARAMETER CONDITIONS MIN TYP MAX UNITS
PWM CONTROLLER
Operational Input Voltage I(V
REF
) = 0µA
l
V
IN
OFF 25 V
V
IN
Quiescent Current I(V
REF
) = 0µA, I
SENSE
= OC = Open 5.2 6.5 mA
V
IN
Start-up Current (LT1952) FB = 0V, SS_MAXDC = 0V (Notes 4, 9)
l
460 700 µA
V
IN
Start-up Current (LT1952-1) FB = 0V, SS_MAXDC = 0V (Notes 4, 9)
l
400 575 µA
V
IN
Shutdown Current SD_V
SEC
= 0V 240 350 µA
SD_V
SEC
Threshold 10V < V
IN
< 25V
l
1.261 1.32 1.379 V
SD_V
SEC (ON)
Current SD_V
SEC
= SD_V
SEC
Threshold + 100mV 0 µA
SD_V
SEC (OFF)
Current SD_V
SEC
= SD_V
SEC
Threshold – 100mV 8.3 10 11.7 µA
V
IN ON
(LT1952)
l
14.25 15.75 V
V
IN OFF
(LT1952)
l
8.75 9.25 V
V
IN HYSTERESIS
(LT1952)
l
3.75 5.5 6.75 V
V
IN ON
(LT1952-1) E-, I-Grades
MP-Grade
l
l
7.75
7.75
8.13
8.3
V
V
V
IN OFF
(LT1952-1)
l
6.5 6.82 V
V
IN HYSTERESIS
(LT1952-1)
l
0.95 1.25 V
V
REF
Output Voltage I(V
REF
) = 0µA
l
2.425 2.5 2.575 V
Line Regulation I(V
REF
) = 0µA, 10V < V
IN
< 25V 1 10 mV
Load Regulation 0µA < I(V
REF
) < 2.5mA 1 10 mV
OSCILLATOR
Frequency: f
OSC
R
OSC
= 178k, FB = 1V, SS_MAXDC = 1.84V
l
165 200 240 kHz
Minimum Programmable f
OSC
Maximum Programmable f
OSC
R
OSC
= 365k, FB = 1V
R
OSC
= 64.9k, COMP = 2.5V, SD_V
SEC
= 2.64V
80
440
100
500
120
560
kHz
kHz
SYNC Input Resistance 18 kΩ
SYNC Switching Threshold FB = 1V 1.5 2.2 V
SYNC Frequency/f
OSC
FB = 1V (Note 7) 1.25 1.5
f
OSC
Line Reg FB = 1V, R
OSC
= 178k; 10V < V
IN
< 25V,
SS_MAXDC = 1.84V
0.05 0.33 %/V
V
ROSC
R
OSC
Pin voltage 1 V
ERROR AMPLIFIER
FB Reference Voltage 10V < V
IN
< 25V, V
OL
+ 0.2V < COMP < V
OH
– 0.2
l
1.201 1.226 1.250 V
FB Input Bias Current FB = FB Reference Voltage –75 –200 nA
Open Loop Voltage Gain V
OL
+ 0.2V < COMP < V
OH
– 0.2 65 85 dB
Unity Gain Bandwidth (Note 6) 3
MHz
COMP Source Current FB = 1V, COMP = 1.6V –4 –9 mA
COMP Sink Current COMP = 1.6V 4 10 mA
COMP Current (Disabled) FB = V
REF
, COMP = 1.6V 18 23 28 µA
COMP High Level: V
OH
FB = 1V, I
(COMP)
= –250µA 2.7 3.2 V
COMP Active Threshold FB = 1V, SOUT Duty Cycle > 0 % 0.7 0.8 V
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). COMP = open, FB = 1.4V, R
OSC
= 178k, SYNC = 0V,
SS_MAXDC = V
REF
, V
REF
= 0.1µF, SD_V
SEC
= 2V, BLANK = 121k, DELAY = 121k, I
SENSE
= 0V, OC = 0V, OUT = 1nF, V
IN
= 15V, SOUT = open,
unless otherwise specified.
ELECTRICAL CHARACTERISTICS