AAT3125ISN-T1 データシートの表示（PDF） - Analog Technology Inc

部品番号

コンポーネント説明

一致するリスト

AAT3125ISN-T1

USB OTG 5V Charge Pump

Analog Technology Inc 

AAT3125

USB OTG 5V Charge Pump

Functional Block Diagram

C1+ C1- C2+ C2-

IN

5V Charge Pump

OC

10mA

4.0

SR

Control

EN

UVLO

OTMP

4.4

2.0

Voltage

Reference

0.6

OUTCP

OUT

POK1

POK2

SESDET

SRRDY

Functional Description

Charge Pump

The charge pump uses a 1.5X topology; the two

flying capacitors are charged in series and dis-

charged in parallel. Using this topology, output cur-

rent is approximately 2/3 input current. Since the

power bus in battery-operated devices that use a

single cell Lithium-Ion/Polymer battery ranges from

3V to 4.5V, output voltage above 4.4V can be

maintained. Output voltage is regulated to 5V and

output current is limited by the value of RCS. The

charge pump is designed to operate safely with

any combination of input and output voltages.

Current is not allowed to flow from OUT to IN.

10mA Current Source

A 10mA current source supplies current to OUT for

VBUS pulsing during SRP. During VBUS pulsing, the

length of time needed to charge capacitance con-

nected to OUT distinguishes between non-SRP

capable devices and SRP capable devices. Using

10mA, SESDET should rise about 7ms after

8

GND

SRRDY rises when an OTG device is connected.

With a non-OTG device connected, this period is at

least 70ms. 10mA should not damage non-SRP

capable hosts that allow reverse current flow from

the bus. Current is not allowed to flow from OUT

to IN through the current source.

SESDET (MicroPower Voltage

Detector)

The SESDET open drain output signals the use of

SRP while the system is acting as the A device.

OUT powers this detector because the local 5V

bus may not be powered when the B device initi-

ates SRP. Since VBUS provides no more than

150µA to OUT, the detector consumes only 7µA.

SRRDY Voltage Detector

The SRRDY open drain output signals that VBUS is

ready for SRP. SRRDY is powered by IN and is

active as long as IN is above the UVLO level.

SRRDY is true (low) when OUT is below the

SRRDY threshold (0.6V nom). SRRDY is false

3125.2005.1.1.3

Share Link: