LTC3721-2 LINER [Linear Technology], LTC3721-2 Datasheet - Page 20

• Manufacturer Part Number: LTC3721-2
• Description: Synchronous Rectifier Driver for Forward Converters
• Manufacturer: LINER [Linear Technology]

LTC3900
Typical applicaTion
PART NUMBER
LT1952/LT1952-1
LTC3901
LT4430
LT1431
LTC3726/LTC3725 Synchronous No Opto Forward Converter Controller Chip Set Ideal for Medium Power 24V or 48V Input Isolated Applications
LTC3723-1/
LTC3723-2
LTC3721-1/
LTC3721-2
LTC3722/
LTC3722-2
20
relaTeD parTs
0.47µF
0.1µF
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone]
115k
59k
DESCRIPTION
Synchronous Forward Converter Controllers
Secondary Side Synchronous Driver for Push-Pull and Full
Bridge Converters
Secondary Side Optocoupler Driver
Programmable Reference
Synchronous Push-Pull Controllers
Nonsynchronous Push-Pull Controllers
Synchronous Phase Modulated Full Bridge Controllers
13.2k
27k
10k
●
370k
FAX: [phone]
36V to 72V Input to 12V at 20A “No Optocoupler” Synchronous “Bus Converter”
7
3
9
5
6
1
2
SD_V
R
BLANK
SS_MAXDC
V
COMP
FB = 1.23V
R
OSC
LTC3900-Based Synchronous “Bus Converter” Efficiency vs Load Current
= 2.5V
36V TO 72V
SEC
LT1952
V
IN
DELAY
I
PGND
●
SENSE
SOUT
GND
OUT
V
47k
82k
OC
www.linear.com
IN
14
15
8
13
12
11
10
16
V
96.0
95.5
95.0
94.5
94.0
93.5
93.0
U1
18V
4
BAT
760
6
470
39k
BCX55
12V
8
V
LOAD CURRENT (A)
U1
2.2µF , 100V
EFFICIENCY
10
1µF
PH21NQ15
220pF
BAS516
POWER LOSS
0.1µF
12
9m
×2
×2
14
PA0815.002
COMMENTS
Ideal for Medium Power 24V or 48V Input Isolated Applications
Similar to the LTC3900, Used in Full Bridge and Push-Pull
Converters
Optocoupler Driver with Precise Reference Voltage
Adjustable Shunt Voltage Regulator with 100mA Sink Capability
High Efficiency with On-Chip MOSFET Drivers
Minimizes External Components, On-Chip MOSFET Drivers
Ideal for High Power 24V or 48V Input Applications
16
V
V
•
•
IN
OUT
•
= 48V
18
= 12V
3900 TA07b
1nF
Q4470-B
1µF
• •
20
BIAS
16
12
8
4
8V
Si7370
×2
5
6
4
8
560
FG
GND
V
SYNC
CC
LTC3900
PH4840
L1: PULSE PA1494.242
ALL CAPACITORS ARE TDK, X5R CERAMIC
TIMER
CS
CS
×2
CG
+
–
15k
R
 LINEAR TECHNOLOGY CORPORA TION 2003
3
1
2
7
T
BIAS
8V
1nF
C
2.4µH
T
L1
10k
10k
10k
LT 0511 REV B • PRINTED IN USA
3900 TA07a
C
33µF , 16V
X5R, TDK
×3
V
12V, ±10%,
20A MAX
OUT
OUT
3900fb