TPS23755 IEEE 802.3at PoE PD with No-Opto Flyback DC-DC Controller |


IEEE 802.3at PoE PD with No-Opto Flyback DC-DC Controller



The TPS23755 device combines a Power over Ethernet (PoE) powered device (PD) interface, a 150-V switching power FET, and a current-mode DC-DC controller optimized for flyback topology. The high level of integration along with primary side regulation (PSR), spread spectrum frequency dithering (SSFD), and advanced startup makes the TPS23755 an ideal solution for size-constrained applications. The PoE implementation supports the IEEE 802.3at standard as a 13-W, Type 1 PD.

The PSR feature of the DC-DC controller uses feedback from an auxiliary winding for control of the output voltage, eliminating the need for external shunt regulator and optocoupler. It is optimized for operation with secondary side diode rectifier (typically 12-V output or higher). Typically, the converter operates in continuous conduction mode (CCM) at a switching frequency of 250 kHz.

SFFD and slew rate control helps to minimize the size and cost of the EMI filter. Advanced Startup allows the use of minimal bias capacitor while simplifying converter startup and hiccup design.

Secondary auxiliary power detect capability provides priority for a secondary side power adapter, while ensuring smooth transition to and from PoE input power, with no efficiency or thermal trade-off.

The DC-DC controller features internal soft-start, slope compensation, and blanking. For non-isolated applications, the buck topology is also supported by the TPS23755.


  • Complete IEEE 802.3at PD Solution for Type 1 PoE
    • Ethernet Alliance (EA) Logo Certified Designs Available
    • Robust 100-V, 0.36-Ω (typ) Hotswap MOSFET
    • Programmable Classification Level
  • Integrated PWM Controller with 0.77-Ω (typ) 150-V Power MOSFET
    • Flyback Controller with PSR
      • Supports CCM Operation with Secondary Side Diode Rectifier
      • ±3% (typ, 12-V Output) Load Regulation (5%-100% range)
    • Supports Low-side Switch Buck Topology
    • Adjustable Switching Frequency with Synchronization
    • Advanced Startup
    • Programmable Slew Rate and Frequency Dithering for Enhanced EMI Reduction
  • Secondary Side Adapter Priority Control with Smooth Transition
  • –40°C to 125°C Junction Temperature Range
  • Small 6-mm x 4-mm VSON Package

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Part number Order Vin (Min) (V) Vin (Max) (V) PoE current limit (Min) (mA) PoE inrush limit (Typ) (mA) rDS(on) per FET (Typ) (mOhms) PoE standards supported PD power level DC/DC control Fault response Features Package Group Package size: mm2:W x L (PKG) Switching frequency
TPS23755 Order now 10.2     57     405     140     360     802.3at Type 1 (802.3af)     13W     PD and DC/DC     Auto Retry     Advanced startup
Error Amplifier
Integrated Switching FET
Primary-Side Regulation
Secondary Side Adapter Priority
Spread Spectrum Frequency Dithering
Thermal Shutdown    
VSON | 23     23VSON: 24 mm2: 4 x 6 (VSON | 23)     Programmable
TPS23753A Order now 9.3     57     405     140     700     802.3at Type 1 (802.3af)     13W     PD and DC/DC     Auto Retry     Primary Side Adapter Priority
Thermal Shutdown    
TSSOP | 14     14TSSOP: 32 mm2: 6.4 x 5 (TSSOP | 14)     Programmable
TPS23757 Order now 9.3     57     400     140     430     802.3at Type 1 (802.3af)     13W     PD and DC/DC     Auto Retry     Primary Side Adapter Priority
Second Gate Drive
Thermal Shutdown    
TSSOP | 20     20TSSOP: 42 mm2: 6.4 x 6.5 (TSSOP | 20)     Programmable
TPS23770 Order now 0     67     405     140     600     802.3at Type 1 (802.3af)     13W     PD and DC/DC     Auto Retry     Error Amplifier
Thermal Shutdown    
HTSSOP | 20     20HTSSOP: 42 mm2: 6.4 x 6.5 (HTSSOP | 20)     Programmable