IEEE 802.3at PoE Interface and Green-mode DC/DC Controller - TPS23751


IEEE 802.3at PoE Interface and Green-mode DC/DC Controller



The TPS23751 is a 16-pin integrated circuit that combines a Power-over-Ethernet (PoE) powered device (PD) interface and a current-mode DC-DC controller optimized specifically for applications requiring high efficiency over a wide load range.

The PoE interface implements type-2 hardware classification per IEEE 802.3at. It also includes an auxiliary power detect (APD) input and a disable function (DEN). A 0.5-Ω, 100-V pass MOSFET minimizes heat dissipation and maximizes power utilization.

The DC-DC controller features internal soft-start, a bootstrap startup current source, current-mode control with slope compensation, blanking, and current limiting. Efficiency is enhanced at light loads by disabling synchronous rectification and entering variable frequency operation (VFO).

The TPS23752 is a 20-pin extended version of the TPS23751 with the addition of a Sleep Mode feature. Sleep Mode disables the converter to minimize power consumption while still generating the Maintain Power Signature (MPS) required by IEEE802.3at.


  • IEEE 802.3at Classification With Status Flag
  • High Efficiency Solutions Over Wide Load Range
  • Powers Up to 25.5 W PDs
  • Robust 100 V, 0.5 Ω Hotswap MOSFET
  • Synchronous Rectifier Disable Signal
  • PowerPAD™ TSSOP Packages
  • Complete PoE Interface Plus DC-DC Controller
  • Adapter ORing Support
  • Programmable Frequency
  • TPS23752 Supports Ultra-Low Power Sleep
  • –40°C to 125°C Junction Temperature Range

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Parametrics Compare all products in Powered Device

Duty Cycle (%)
Fault Response
Switching Frequency
rDS(on) per FET (Typ) (mOhms)
Auxiliary/Local Power Support
Driven/Active Clamp (Second Gate Drive)
PoE Current Limit (Min) (mA)
Error Amplifier
PD Power Level
PoE Inrush Limit (Typ) (mA)
PoE Standards Supported
PoE I/F & DC DC Control
Auxiliary Power Rails Supported
Frequency (Max) (kHz)
Approx. Price (US$)
TPS23751 TPS23752 TPS23754 TPS23754-1 TPS23756
85     85     78     78     78    
Auto Retry     Auto Retry     Auto Retry     Auto Retry     Auto Retry    
Programmable     Programmable     Programmable
    Unified     Unified     Unified    
450     450     430     430     430    
    Programmable     Programmable     Programmable    
No     No     Yes     Yes     Yes    
850     850     850     850     850    
No     No     No     No     No    
25W     25W     25W     25W     25W    
140     140     140     140     140    
802.3at Type 1 (802.3af)
802.3at Type 2    
802.3at Type 1 (802.3af)
802.3at Type 2    
802.3at Type 1 (802.3af)
802.3at Type 2    
802.3at Type 1 (802.3af)
802.3at Type 2    
802.3at Type 1 (802.3af)
802.3at Type 2    
1     1     24-57V     24-57V     12-57V    
Adjustable     Adjustable          
16HTSSOP     20HTSSOP     20HTSSOP     20HTSSOP     20HTSSOP    
1.10 | 1ku     1.10 | 1ku     1.25 | 1ku     1.25 | 1ku     1.30 | 1ku