Copyright

© ANPEC Electronics Corp.

Rev. A.6 - Sep., 2012

APW8813/A

www.anpec.com.tw

1

ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and

advise customers to obtain the latest version of relevant information to verify before placing orders.

DDR2 And DDR3 Power Solution Synchronous Buck Controller With 1.5A LDO

Features

General Description

Buck Controller (VDDQ)

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High Input Voltages Range from 3V to 28V Input

Power

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Provide 1.8V (DDR2), 1.5V (DDR3) or Adjustable

Output Voltage from 0.75V to 5.5V

- ±1% Accuracy Over-Temperature

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Integrated MOSFET Drivers and Bootstrap Diode

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Excellent Line and Load Transient Responses

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PFM Mode for Increased Light Load Efficiency

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Constant-On-Time Controller Scheme

- Switching Frequency Compensation for PWM

Mode

- Adjustable Switching Frequency from 100kHz

to 550kHz in PWM Mode with DC Output Current

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Integrated MOSFET Drivers and Bootstrap Diode

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S3 and S5 Pins Control The Device in S0, S3, or

S4/S5 State

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Power Good Monitoring

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70% Under-Voltage Protection (UVP)

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125% Over-Voltage Protection (OVP)

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Adjustable Current-Limit Protection

- Using Sense Low-Side MOSFET R

DS(ON)

±1.5A LDO Section (VTT)

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Souring or Sinking Current up to 1.5A

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Fast Transient Response for Output Voltage

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Output Ceramic Capacitors Support at Least

10

µF MLCC

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VTT and VTTREF Track at Half the VDDQSNS by

Internal Divider

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±20mV Accuracy for VTT and VTTREF

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Independent Over-Current-Limit (OCL)

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Thermal Shutdown Protection

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QFN-24 4mmx4mm Thin Package (TQFN4x4-24A)

for APW8813 and QFN-20 3mmx3mm Thin

Package (TQFN3x3-20) for APW8813A

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Lead Free and Green Devices Available

(RoHS Compliant)

Applications

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DDR2, and DDR3 Memory Power Supplies

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SSTL-2 SSTL-18 and HSTL Termination

The APW8813/A integrates a synchronous buck PWM

controller to generate VDDQ, a sourcing and sinking LDO

linear regulator to generate VTT. It provides a complete

power supply for DDR2 and DDR3 memory system. It

offers the lowest total solution cost in system where space

is at a premium.

The APW8813/A provides excellent transient response

and accurate DC voltage output in either PFM or PWM

Mode. In Pulse Frequency Mode (PFM), the APW8813/A

provides very high efficiency over light to heavy loads with

loading-modulated switching frequencies. On TQFN4x4-

24A package, the Forced PWM Mode works nearly at con-

stant frequency for low-noise requirements.

The APW8813/A is equipped with accurate current-limit,

output under-voltage, and output over-voltage protections.

A Power-On-Reset function monitors the voltage on V

CC

prevents wrong operation during power on.

The LDO is designed to provide a regulated voltage with

bi-directional output current for DDR-SDRAM termination.

The device integrates two power transistors to source or

sink current up to 1.5A. It also incorporates current-limit

and thermal shutdown protection.

The output voltage of LDO tracks the voltage at VTTREF

pin. An internal resistor divider is used to provide a half

voltage of VDDQ for VTTREF and VTT Voltage. The VTT

output voltage is only requiring 20

µF of ceramic output

capacitance for stability and fast transient response. The

S3 and S5 pins provide the sleep state for VTT (S3 state)

and suspend state (S4/S5 state) for device, when S5 and

S3 are both pulled low the device provides the soft-off for

VTT and VTTREF.

The APW8813/A is available in 4mmx4mm 24-pin TQFN

package, and the APW8813A is available in 3mmx3mm

20-pin TQFN package.