SY23218XTQ (SY56816XTQ)

IEEE 802.3af/at Compliant PoE PD Interface with High Efficiency PSR/SSR Flyback Converter

Parameters
Features
Description

Part number	SY23218XTQ
PoE standards	af/at
Vin (min) (V)	10
Vin (max) (V)	57
PD (max)(W)	<25W
Ron (typ) (mΩ)	450
Power conversion FETs integrated	YES
Breakdown voltage (V)	150V/0.07Ω
Features	PSR/SSR Flyback,Hiccup UVP,Hiccup SCP,Hiccup OCP,Hiccup OVP,Hiccup OTP
Package	QFN4×6-38
Operating temperature range(°C)	-40 to 125
Functional safety category

Fully Compatible with 802.3af/at Specifications
100V 0.45Ω PD Integrated Pass Switch
30W maximum power
100mA PD Inrush Current Limit
900mA PD Normal Operation Current Limit
Auxiliary Adaptor ORing Support
Flexible Topology:
Primary-Side Regulated (PSR) Flyback (250kHz/400kHz Selectable)
Secondary-Side Regulated (SSR) Flyback (Programmable Frequency)
Integrated with 150V 70mΩ Power MOSFET
Output Diode Compensation in PSR Mode
Cycle-by-Cycle Current Sense Limit
Precision Voltage Reference
Frequency Modulation for EMI reduction
Programmable Soft-start
OLP Compensation for Wide-input Range
Externally Programmable Thermal Shutdown
Programmable Line Under Voltage Lockout (UVLO) with Adjustable Hysteresis
Hiccup Protection for OLP, SCP, OVP and Thermal Shutdown

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Evaluation Board

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

EVB_SY23218XTQ

The EVB_SY23218XTQ is intended for evaluating IEEE 802.3af/at Compliant PoE PD Interface with High Efficiency PSR/SSR Flyback Converter

Technical Documentation

Title	Date
Silergy_Catalog_Q2_2026	2026-06-12