LT1952EGN#PBF Linear Technology, LT1952EGN#PBF Datasheet - Page 20

• 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

APPLICATIONS INFORMATION
LT1952/LT1952-1
20
Figure 12. LT1952-Based Synchronous Forward Converter
Effi ciency vs Load Current (For Circuit in Figure 14)
0.1μF
100k
Q1: PHM15NQ20 PHILIPS
SOUT
22k
98
96
94
92
90
88
86
115k
0.1μF
0
16
5
6
2
3
4
SOUT
SS_MAXDC
V
FB
R
SYNC
BLANK DELAY
REF
OSC
5
9
40k
LT1952-1
LOAD CURRENT (A)
10
Figure 14. 36V to 72V Input to 5V at 20A Synchronous Forward Converter
12
33k
SD_V
I
COMP
SENSE
PGND
GND
OUT
0.1μF
SEC
V
OC
IN
15
1μF
10V
7
14
11
10
13
8
15
1
V
V
f
OSC
IN
OUT
BIAS
= 48V
20
= 300kHz
= 5V
1952 F12
9.53k
4.75k
36V TO 72V
25
6
5
4
10V
HCPL-M453
BIAS
+V
IN
SOUT
475k
18.2k
1
2
3
220pF
1k
2.2μF
100V
T2
X5R
C
IN
Figure 13. Output Voltage Transient Response
(6A to 12A Load Step at 6A/μs)
(200mV/DIV)
(5A/DIV)
Q1
560Ω
0.015Ω
SYNC
V
I
OUT
OUT
PA0491
0A
T1
X5R
+V
1μF
C9, 6.8nF
0UT
7V
BIAS
Q2
PH3830
38.3k
270Ω
R14
1.2k
R15
R13
20μs/DIV
1
2
3
4
5
6
8
R16
12.4k
V
CG
PGND
GND
OPTO
V
V
DD
COMP
FB
LTC1698
Q3
PH3830
I
PA1393.152
SYNC
+I
–I
COMP
V
OVP
AUX
SNS
SNS
FG
1952 F13
L1
16
15
14
13
12
11
9
SYNC
1952 F14
C
100μF
X5R
2
+V
5V
20A
01
19521fd
0.1μF
0UT