TPS2383 datasheet(2/27 Pages) TI

2 / 27 page

TPS2383

SLUS559B − APRIL 2003 − REVISED JULY 2004

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DESCRIPTION

The TPS2383 family of products are power sourcing equipment power managers (PSEPM) that are compliant

to the power-over-ethernet (PoE) IEEE 802.3af Standard. A PSEPM port can discover, classify and deliver

power to a powered device (PD) capable of accepting PoE twisted pair cable. The TPS2383 is fully

programmable by the user. This allows for the detection and powering of both fully compliant 802.3 devices as

well as custom detection of legacy devices.

The TPS2383 PSEPM can individually manage power for up to eight ethernet ports. All operations of the

TPS2383 are controlled through register read and write operations over a standard (slave) I2C serial interface.

The TPS2383 has dual SDA lines to allow easy application of opto-coupler circuitry to maintain ethernet port

isolation when a ground based controller is used. Each TPS2383 has five selection pins making it possible to

address up to 32 devices on the I2C bus and allows individual control and monitoring of up to 256 ethernet ports

from a single master I2C controller. Per-port write registers initiate and manipulate the flow of the discovery,

classification, and power-up states while the read registers contain status information of the enable process,

faults, classification value, and real time port operating current and voltage. Per-port status LED drivers are

provided which can be manually controlled through the serial I/O.

The TPS2383 is available in a full function 64-pin LQFP.

External N-channel MOSFETs switch port power. High-voltage (HV) gate drive ensures that these FETs are fully

enhanced, resulting in lower power dissipation and enabling the use of lower costs FETs. The TPS2383

generates its HV gate supply from the 48-V port power, simplifying system power supply design. An external

3.3-V digital supply is also used. This supply can be active when 48-V power is not present which allows the

user to access the part through the serial I/O in this case. A 5-V analog supply is used to power port LEDs and

internal analog functions. Due to the very low quiescent current, both the 3.3-V and 5-V supply can be generated

from the +48-V power bus with minimal external components. An internal power-on-reset (POR) circuit with an

ORed external input pin resets all registers positions to a known safe state upon power up.

TPS2383 Datasheet(PDF) 2 Page - Texas Instruments