LINEAR TECHNOLOGY LTC1628 LTC1628-PG User Guide and Manual
Summary
Achieve reliable, high-efficiency power conversion with this dual, two-phase synchronous step-down switching regulator. Designed for advanced DC power distribution systems, it features low dropout operation, wide voltage range support (3.5V–36V), and robust protection circuitry crucial for sensitive electronics. The manual provides comprehensive technical details, including operational modes, schematics, and electrical specifications. This controller is ideal for engineers developing portable instruments, notebook computers, and deep-cycle battery-operated digital devices requiring precise and stable power delivery.
Page 1 Text Content
LTC1628/LTC1628-PG High Efficiency, 2-Phase
Synchronous Step-Down Switching Regulators
FEATURES DESCRIPTIO Out-of-Phase Controllers Reduce Required Input The LTC®1628/LTC1628-PG are high performance dual Capacitance and Power Supply Induced Noise step-down switching regulator controllers that drive all OPTI-LOOP® Compensation Minimizes COUT N-channel synchronous power MOSFET stages. A con- ±1% Output Voltage Accuracy stant frequency current mode architecture allows adjust- Dual N-Channel MOSFET Synchronous Drive ment of the frequency up to 300k Hz. Power loss and noise
Power Good Output Voltage Monitor (LTC1628-PG) due to the ESR of the input capacitors are minimized by DC Programmed Fixed Frequency 150k Hz to 300k Hz operating the two controller output stages out of phase.
Wide VIN Range: 3.5V to 36V Operation
OPTI-LOOP compensation allows the transient response
Very Low Dropout Operation: 99% Duty Cycle
to be optimized over a wide range of output capacitance and
Adjustable Soft-Start Current Ramping
ESR values. The precision 0.8V reference and power good
Foldback Output Current Limiting
output indicator are compatible with future microproces-
Latched Short-Circuit Shutdown with Defeat Option
sor generations, and a wide 3.5V to 30V (36V maximum)
Output Overvoltage Protection
input supply range encompasses all battery chemistries.
Remote Output Voltage Sense
Low Shutdown IQ: 20µA A RUN/SS pin for each controller provides both soft-start 5V and 3.3V Standby Regulators and optional timed, short-circuit shutdown. Current Selectable Constant Frequency or Burst Mode® foldback limits MOSFET dissipation during short-circuit Operation conditions when overcurrent latchoff is disabled. Output Available in 5mm × 5mm QFN and overvoltage protection circuitry latches on the bottom 28-Pin SSOP Packages MOSFET until VOUT returns to normal. The FCB mode pin can select among Burst Mode, constant frequency mode
APPLICATIO S and continuous inductor current mode or regulate a
secondary winding. The LTC1628-PG includes a power
Notebook and Palmtop Computers, PDAs
good output pin that replaces the FLTCPL, fault coupling
Battery Chargers
control pin of the LTC1628.
Portable Instruments
, LTC and LT are registered trademarks of Linear Technology Corporation.
Battery-Operated Digital Devices OPTI-LOOP and Burst Mode are registered trademarks of Linear Technology Corporation. DC Power Distribution Systems
VIN CIN 5.2V TO 28V
TYPICAL APPLICATIO 1µF 22µF
D4 CERAMIC 50V
VIN INTVCC
CERAMIC
M1 TG1 TG2 M3
L1 CB1, 0.1µF CB2, 0.1µF L2
6.3µH BOOST1 BOOST2 6.3µH
SW1 SW2 LTC1628
D1 M2 BG1 BG2 D2M4
SGND PGND
SENSE1+ SENSE2+
RSENSE1 1000p F RSENSE2
VOUT1 SENSE1– SENSE2– VOUT2
5V VOSENSE1 VOSENSE2 3.3V 5A R2 R4 5A
ITH1 ITH2
COUT1 105k CC1 CC2 63.4k
1% R1 RUN/SS1 RUN/SS2 R3 +COUT
6V RC1 CSS1 CSS2 RC2 6V
SP 15k 0.1µF 0.1µF 15k SP
M1, M2, M3, M4: FDS6680A
Figure 1. High Efficiency Dual 5V/3.3V Step-Down Converter
1628fb
Page Summary Contents For LINEAR TECHNOLOGY LTC1628 LTC1628-PG User Guide and Manual
Manual Details
| Brand | Linear |
|---|---|
| Pages | 32 |
| File Size | 381.58 KB |
| Published | June 05, 2026 |
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Frequently Asked Questions
What is the input supply voltage range for this controller?
The operating input supply voltage range is from 3.5V to 36V.
Does the LTC1628 support soft-start and shutdown features?
Yes, a dedicated RUN/SS pin provides both optional timed short-circuit shutdown and soft-start for each controller side.
How can the output voltage be monitored when using the -PG version?
The LTC1628-PG includes a Power Good Output Voltage Monitor (PGOOD) to provide fault signaling on the bottom.