TECHNICAL NOTE

High-performance Regulator IC Series for PCs

Termination Regulators

for DDR-SDRAM

BD3538F, BD3538HFN

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Description

BD3538F/HFN is a termination regulator compatible with JEDEC DDR-SDRAM, which functions as a linear power supply

incorporating an N-channel MOSFET and provides a sink/source current capability up to 1A respectively. A built-in

high-speed OP-AMP specially designed offers an excellent transient response. Requires 3.3 volts or 5.0 volts as a bias

power supply to drive the N-channel MOSFET.

Has an independent reference voltage input pin (VDDQ) and an

independent feedback pin (VTTS) to maintain the accuracy in voltage required by JEDEC, and offers an excellent output

voltage accuracy and load regulation. Also has a reference power supply output pin (VREF) for DDR-SDRAM or a

memory controller. When EN pin turns to “Low”, VTT output becomes “Hi-Z” while VREF output is kept unchanged,

compatible with “Self Refresh” state of DDR-SDRAM.

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Features

1) Incorporates a push-pull power supply for termination (VTT)

2) Incorporates a reference voltage circuit (VREF)

3) Incorporates an enabler

4) Incorporates an undervoltage lockout (UVLO)

5) Employs SOP8 package

6) Employs HSON8 package

7) Incorporates a thermal shutdown protector (TSD)

8) Operates with input voltage from 2.7 to 5.5 volts

9) Compatible with Dual Channel (DDR-II)

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Use

Power supply for DDR I/II/III - SDRAM

Oct. 2008