SY81154UART

High Efficiency, 800kHz, 4A, 18V Input Synchronous Buck Converter

SY81154UART High Efficiency, 800kHz, 4A, 18V Input Synchronous Buck Converter Datasheet

Parameters
Features
Description

Part number	SY81154UART
Channel(#)	1
Vin (min) (V)	4.5
Vin (max) (V)	18
Switching frequency (min)(kHz)
Switching frequency (max)(kHz)	800
Vout (min) (V)	0.6
Vout (max) (V)	9.2
Iout (max) (A)	4
Vout2 (min)(V)
Vout2 (max )(V)
Iout2 (max)(A)
Vref accuracy (±%)	1
Vout accuracy(±%)
Control mode	COT+Ripple
Duty cycle (max)(%)	60
Operation mode	USM
Iq (typ) (uA)
Features	Hic-cup SCP
Package	SOT563
Operating temperature range(°C)	-40°C to 125°C
Functional safety category

· Low R_DS(ON) for Internal MOSFETs: 65mΩ Top, 30mΩ Bottom

· Wide Input Voltage Range: 4.5V ~ 18V

· Up to 4A Output Current

· Precise ±1% 0.6V Reference under -40°C~125°C

· Precise EN Threshold

· USM Light Load Operation

· Internal Soft-Start Limits the Inrush Current

· 800kHz Switching Frequency Minimizes the External Components

· Constant On-time and Ripple-Based Control to Achieve Fast Transient Responses

· Cycle-by-Cycle Valley and Peak Current Limit Protection

· Hic-Cup Mode Output Under Voltage Protection

· Auto-Recovery Mode Over Temperature Protection

· Input Under Voltage Lockout (UVLO)

· RoHS-Compliant and Halogen-Free

· Compact Package: SOT563

The SY81154U high efficiency 800kHz synchronous buck converter operates over a wide input voltage range of 4.5V to 18V, and can deliver an output current up to 4A. It integrates a top MOSFET and a bottom MOSFET with very low RDS(ON) to minimize conduction loss. The 800kHz pseudo-constant switching frequency enables using small external inductor and capacitor values.

Evaluation Board

Photo of evaluation board
Photo of evaluation board
Photo of evaluation board

EVB_SY81154UART

EVB File

EVB_SY81154UART is intended for evaluating 4A, 18V, 800kHz synchronous buck converter.

Technical Documentation

Title	Date
Silergy_Catalog_Q2_2026	2026-06-12
SOT563	2021-09-27