LT1952
2
1952f
GN PACKAGE
16-LEAD PLASTIC SSOP
1
2
3
4
5
6
7
8
TOP VIEW
16
15
14
13
12
11
10
9
COMP
FB
R
OSC
SYNC
SS_MAXDC
V
REF
SD_V
SEC
GND
SOUT
V
IN
OUT
PGND
DELAY
OC
I
SENSE
BLANK
V
IN
(Note 8) ............................................... –0.3V to 25V
SYNC, SS_MAXDC, SD_V
SEC
, I
SENSE
,
OC, COMP, BLANK, DELAY ......................... –0.3V to 6V
FB ................................................................ –0.3V to 3V
R
OSC
......................................................................................
–50µA
V
REF
.................................................................... –10mA
Operating Junction Temperature Range
(Notes 2, 5) ....................................... –40°C to 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
GN PART
MARKING
T
JMAX
= 125°C, θ
JA
= 110°C/W, θ
JC
= 40°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
1952E
1952I
LT1952EGN
LT1952IGN
ABSOLUTE AXI U RATI GS
W
WW
U
PACKAGE/ORDER I FOR ATIO
UUW
(Note 1)
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. COMP = open, FB = 1.4V, R
OSC
= 178k, SYNC = 0V, SS_MAXDC = V
REF
, V
REF
= 0.1µF, SD_V
SEC
= 2V, BLANK = 40k, DELAY = 40k, I
SENSE
= 0V, OC = 0V, OUT = 1nF, V
IN
= 15V, SOUT = open, unless otherwise specified.
PARAMETER CONDITIONS MIN TYP MAX UNITS
PWM CONTROLLER
Operational Input Voltage I
(VREF)
= 0µA ● V
IN OFF
25 V
V
IN
Quiescent Current I
(VREF)
= 0µA, FB = 0V, I
SENSE
= OC = Open 5.2 6.5 mA
V
IN
Startup Current FB = 0V, SS_MAXDC = 0V (Notes 4, 9) ● 460 700 µA
V
IN
Shutdown Current SD_V
SEC
= 0V 240 350 µA
SD_V
SEC
Threshold 10V < V
IN
< 25V ● 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 9.5 11.2 12.9 µA
V
IN ON
● 12.75 14.25 15.75 V
V
IN OFF
● 8.0 8.75 9.25 V
V
IN HYSTERESIS
● 3.75 5.5 6.75 V
V
REF
Output Voltage I
(VREF)
= 0µA ● 2.425 2.5 2.575 V
Line Regulation I
(VREF)
= 0µA, 10V < V
IN
< 25V 1 10 mV
Load Regulation 0µA < I
(VREF)
< 2.5mA 1 10 mV
OSCILLATOR
Frequency: f
OSC
R
OSC
= 178k, FB = 1V ● 165 200 240 kHz
Minimum Programmable f
OSC
R
OSC
= 365k 80 100 120 kHz
Maximum Programmable f
OSC
R
OSC
= 64.9k, COMP = 2.5V, SD_V
SEC
= 2.64V 440 500 560 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, 0.05 0.33 %/V
SS_MAXDC = 1.84V
V
ROSC
R
OSC
Pin voltage 1 V