Document
U U
FEATURES
■ High Efficiency Synchronous Push-Pull PWM ■ 1.5A Sink, 1A Source Output Drivers ■ Supports Push-Pull, Full-Bridge, Half-Bridge, and
Forward Topologies ■ Adjustable Push-Pull Dead-Time and Synchronous
Timing ■ Adjustable System Undervoltage Lockout and
Hysteresis ■ Adjustable Leading Edge Blanking ■ Low Start-Up and Quiescent Currents ■ Current Mode (LTC3723-1) or Voltage Mode
(LTC3723-2) Operation ■ Single Resistor Slope Compensation ■ VCC UVLO and 25mA Shunt Regulator ■ Programmable Fixed Frequency Operation to 1MHz ■ 50mA Synchronous Output Drivers ■ Soft-Start, Cycle-by-Cycle Current Limiting and
Hiccup Mode Short-Circuit Protection ■ 5V, 15mA Low Dropout Regulator ■ Available in 16-Pin SSOP Package
U APPLICATIO S
■ Telecommunications, Infrastructure Power Systems ■ Distributed Power Architectures
LTC3723-1/LTC3723-2
Synchronous Push-Pull PWM Controllers
DESCRIPTIO
The LTC®3723-1/LTC3723-2 synchronous push-pull PWM controllers provide all of the control and protection functions necessary for compact and highly efficient, isolated power converters. High integration minimizes external component count, while preserving design flexibility.
The robust push-pull output stages switch at half the oscillator frequency. Dead-time is independently programmed with an external resistor. Synchronous rectifier timing is adjustable to optimize efficiency. A UVLO program input provides precise system turn-on and turn off voltages. The LTC3723-1 features peak current mode control with programmable slope compensation and leading edge blanking, while the LTC3723-2 employs voltage mode control with voltage feedforward capability.
The LTC3723-1/LTC3723-2 feature extremely low operating and start-up currents. Both devices provide reliable short-circuit and overtemperature protection. The LTC3723-1/LTC3723-2 are offered in a 16-pin SSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
Isolated Push-Pull Converter
VOUT VIN
FROM AUXILIARY
WINDING
VREF
UVLO
DRVA
SPRG VCC DPRG
DRVB CS
CT
SDRA
RLEB
SDRB VREF
LTC3723-1
SS
COMP
FB GND
••
ME SYNC
LTC3901
MF
VREF VOUT
VOUT
V+ COLL
LT1431
RREF
GND-F GND-S
372312 TA01
372312f
1
LTC3723-1/LTC3723-2
U WW W
ABSOLUTE AXI U RATI GS (Note 1)
VCC to GND (Low Impedance Source) .......– 0.3V to 10V (Chip Self-Regulates at 10.3V)
UVLO to GND ............................................. – 0.3V to VCC All Other Pins to GND (Low Impedance Source) .........................– 0.3V to 5.5V VCC (Current Fed) ................................................. 40mA
UW U PACKAGE/ORDER I FOR ATIO
VREF Output Current ............................... Self-Regulated Operating Temperature (Notes 5,6)
LTC3723E ........................................... – 40°C to 85°C Storage Temperature Range ................. – 65°C to 125°C Lead Temperature (Soldering, 10sec)................... 300°C
TOP VIEW
VREF 1 SDRB 2 SDRA 3 DRVB 4
VCC 5 DRVA 6
GND 7 CT 8
16 SPRG 15 UVLO 14 SS 13 FB 12 RLEB 11 COMP 10 CS 9 DPRG
GN PACKAGE 16-LEAD PLASTIC SSOP
TJMAX = 125°C, θJA = 100°C/W
ORDER PART NUMBER LTC3723EGN-1
GN PART MARKING 37231
Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
TOP VIEW
VREF 1 SDRB 2 SDRA 3 DRVB 4
VCC 5 DRVA 6
GND 7 CT 8
16 SPRG 15 UVLO 14 SS 13 FB 12 DPRG 11 COMP 10 CS 9 RAMP
GN PACKAGE 16-LEAD PLASTIC SSOP
TJMAX = 125°C, θJA = 100°C/W
ORDER PART NUMBER LTC3723EGN-2
GN PART MARKING 37232
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 9.5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Input Supply
VCCUV VCCHY ICCST ICCRN VSHUNT RSHUNT SUVLO
VCC Undervoltage Lockout VCC UVLO Hysteresis Start-Up Current Operating Current Shunt Regulator Voltage Shunt Resistance System UVLO Threshold
SHYST
System UVLO Hysteresis Current
Pulse Width Modulator
Measured on VCC Measured on VCC VCC = VUVLO – 0.3V No Load on Outputs
10.25 10.7
V
3.8
4.2
V
●
145 230
µA
3
8
mA
Current into VCC = 10mA Current into VCC = 10mA to 17mA Measured on UVLO Pin, 10mA into VCC Current Flows Out of UVLO Pin, 10mA into VCC
10.3 10.8
V
1.4
3.5
Ω
4.8
5.0
5.2
V
8.5
10
11.5
µA
ROS
Ramp Offset Voltage
Measured on COMP, RAMP = 0V
0.65
V
IRMP
Ramp Discharge Current
RAMP = 1V, COMP = 0V, CT = 4V, 3723-1 Only
50
mA
372312f
2
LTC3723-1/LTC3723-2
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 9.5V unless otherwise noted.
SYMBOL PARAMETE.