LT1952EGN#PBF Linear Technology, LT1952EGN#PBF Datasheet - Page 9

• Manufacturer Part Number: LT1952EGN#PBF
• Description: IC CTLR PWM SGL SWITCH 16-SSOP
• Manufacturer: Linear Technology

Specifications of LT1952EGN#PBF

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 560kHz
• Duty Cycle: 90%
• Voltage - Supply: 9.25 V ~ 25 V
• Buck: No
• Boost: No
• Flyback: Yes
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SSOP
• Frequency-max: 560kHz
• Number Of Pwm Outputs: 1
• On/off Pin: No
• Adjustable Output: No
• Topology: Flyback/Forward
• Switching Freq: 80 TO 560kHz
• Operating Supply Voltage (max): 25V
• Synchronous Pin: Yes
• Rise Time: 50ns
• Fall Time: 30ns
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 16
• Package Type: SSOP N
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TIMING DIAGRAM
BLOCK DIAGRAM
V
V
I
I
V
V
START
IN
START
IN
IN
IN
LT1952-1
ON = 14.25V
OFF = 8.75V
ON = 7.75V
LT1952
OFF = 6.5V
= 460μA
= 400μA
SD_V
SYNC
R
OSC
SEC
7
3
4
V
V
IN
IN
–
SOUT
OUT
SS_MAXDC
–
OFF
ON
FAULTS TRIGGERING SOFT-START
V
OR
SD_V
OR
OC > 107mV (OVERCURRENT)
IN
1.32V
V
15
+
IN
+
< 8.75V
SEC
1.23V
FB
2
START-UP
INPUT CURRENT (ISTART)
< 1.32V (UVLO)
I
10μA SD_V
0μA SD_V
HYST
+
–
t
DELAY
(VOLTAGE)
ERROR AMPLIFIER
SEC
SEC
> 1.32V
= 1.32V
: PROGRAMMABLE SYNCHRONOUS DELAY
–
+
(TYPICAL 200kHz)
OSC
Figure 1. Timing Diagram
(100 TO 500)kHz
COMP
1.23V
Figure 2. Block Diagram
1
V
REF
6
SOFT-START
LATCH SET
2.5V
SOURCE
2.5mA
SS_MAXDC
RAMP
5
GND
8
–
+
SLOPE COMP
35μA 80% DC
8μA 0% DC
(LINEAR)
DUTY CYCLE
MAXIMUM
ADAPTIVE
0.45V
SOFT-START LATCH RESET:
V
AND
SD_V
AND
OC < 107mV
AND
SS_MAXDC < 0.45V
0mV TO 220mV
CLAMP
IN
> 14.25V (> 8.75V IF LATCH SET BY OC)
SEC
+
–
–
> 1.32V
CURRENT
SENSE
S
R
0.8V (ACTIVE THRESHOLD)
0.45V (RESET THRESHOLD)
0.2V
Q
+
Q
R
S
SOFT-START CONTROL
DELAY
DELAY
ON
12
BLANK
BLANK
LT1952/LT1952-1
9
DRIVER
1952 F01
1A
13V
107mV
+
CURRENT
OVER
>90%
V
REF
50mA
–
12V
1952 BD
11 OC
10
16 SOUT
14
13
OUT
PGND
I
SENSE
19521fd
9