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Copyright © 2016

Microsemi

Page 1 of 20

Rev.2.0, 17-Jan-2017

CPG

– PoE BU

One Enterprise Aliso Viejo, CA 92656 USA

PD70101 / PD70201

Datasheet

Features

 IEEE802.3af and IEEE802.3at

Compliant

 Support for 4-pair Applications of up to

47.7W With a Single IC

 Two-events Classification

Identification With a Level Signal

Indicating Type 1 or Type 2 PSE

 Less Than 10 µA (typical) Offset

Current During Detection

 Signature Resistor is Disconnected

upon Detection

 Programmable Classification Setting

With a Single Resistor

 Integrated 0.6 Ohm Isolating MOSFET

Switch With Inrush Current Limit

 Power Off DC-DC Input Capacitor

Discharge

 100 kHz to 500 kHz Adjustable DC-DC

Switching Frequency

 DC-DC Frequency Can Be

Synchronized to External Clock

 Supports Low Power Mode Operation

for Higher Efficiency 50% Maximum

Duty Cycle

 Soft-start Circuit to Control The Output

Voltage Rise Time

 Two out-of-phase driver stages for

efficient synchronous rectification or

active clamp

 PoE Port Input UVLO with

Programmable Threshold and

Hysteresis

 Internal Differential Amplifier

Simplifying Non-isolated Step Down

Converter

 Over Load and Short Circuit Protection

 RoHS Compliant & Pb-Free

Applications

 IEEE802.3at and IEEE802.3af

powered devices such as IP

phones, WLAN Access Points and

Network Cameras.

 48V Input Telcom/Networks Hot

Swappable Power Supply.

Power Over Ethernet

802.3af/at PD Controller

The PD70101 and PD70201 are integrated Powered Device Interface and

PWM controllers for a DC-DC converter used in IEEE802.3af and

IEEE802.3at applications. The PD70101 can be used for IEEE802.3af or

IEEE802.3at Type 1 applications, while the PD70201 can also be used in

IEEE802.3at Type 2 applications.

A single PD70201 can be used in 4-pair applications which consumes up

to 47.7W.

These devices have a number of features designed to improve efficiency

and reliability:

Detection and Classification: The front end interface includes detection

and

classification

circuitry.

The

detection

signature

resistor

is

disconnected upon completion of the detection phase. The system then

begins the classification phase. Classification can be configured for

Classes 0 to 4 via an external resistor.

The PD70201 includes a

two-events classification identification circuit which generates a flag to

inform the PD application whether the Power Source Equipment (PSE) is

Type 1 or Type 2.

Capacitor: A current limited internal MOSFET switch charges the input

capacitor of the DC-DC converter. This capacitor is discharged in a timely

manner when the input power is removed.

Gate drivers: The PWM DC-DC controller has two built-in gate drivers

designed to swing between VCC and GND. These 2 out-of-phase driver

stages can be configured for synchronous rectification or active clamp.

Peak current mode control: The DC-DC converter employs peak current

mode control for better line and load step response.

The switching

frequency can be set from 100kHz to 500kHz, enabling a size and

efficiency trade off.

Maximum duty cycle is limited to 50% to reduce the power MOSFET

switch voltage to two times the input voltage; a 150V rated MOSFET can

be used for the primary side switch.

The secondary synchronous

MOSFET voltage rating depends on the output voltage and can be higher

or lower than the primary side MOSFET switch.

Soft-start circuit: The devices include a soft-start circuit to control the

output voltage rise time (user settable) at start up, and to limit the inrush

current. An integrated startup bias circuit powers the DC-DC controller,

until the device starts up by the voltage generated by the bootstrap circuit.

Low Voltage Protection Warning and Monitoring: Dual Under Voltage

Lock Out (UVLO), which monitors both the PoE Port Input Voltage and

VCC, ensures reliable operation during any system disturbances.

The

PoE port UVLO has a programmable threshold and hysteresis to enable

tailoring to the desired turn on and turn off voltage.

An internal current sense amplifier with a Kelvin connection allows the use

of an extremely low resistor to measure the current sense threshold

voltage (200 mV) which optimizes efficiency.

Low Power Mode operation is provided to improve efficiency under light

loads such as when the PD is in standby. The user can define at what

power level the unit enters low power mode by means of a single resistor

value.