○Product structure：Silicon monolithic integrated circuit ○This product has no designed protection against radioactive rays

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02.Nov.2015 Rev.001

TSZ22111・14・001

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TSZ02201-0J2J0A900980-1-2

Termination Regulators for DDR-SDRAMs

BD3538F

BD3538HFN

General Description

BD3538F/HFN is a termination regulator that complies

with JEDEC requirements for DDR-SDRAM. This

linear power supply uses a built-in N-channel MOSFET

and high-speed OP-AMPS specially designed to

provide

excellent

transient

response.

It

has

a

sink/source current capability of up to 1A and has a

power supply bias requirements of 3.3V to 5.0V for

driving the N-channel MOSFET. By employing

an

independent reference voltage input (VDDQ) and

a

feedback

pin

(VTTS),

this

termination

regulator

provides excellent output voltage accuracy and load

regulation

as

required

by

JEDEC

standards.

Additionally, BD3538 has a reference power supply

output

(VREF)

for

DDR-SDRAM

or

a

memory

controller. Unlike the VTT output that goes to

“Hi-Z”

state, the VREF output is kept unchanged when EN

input is changed to “Low”, making this IC suitable for

DDR-SDRAM under

“Self Refresh” state.

Features



Incorporates a push-pull power supply for

termination (VTT)



Incorporates a reference voltage circuit (VREF)



Incorporates an enabler



Incorporates an undervoltage lockout (UVLO)



Incorporates a thermal shutdown protector (TSD)



Compatible with Dual Channel (DDR-II)

Applications

Power supply for DDR I / II - SDRAM

Key Specifications

 Termination Input Voltage Range:

1.0V to 5.5V

 VCC Input Voltage Range:

2.7V to 5.5V

 VDDQ Reference Voltage Range:

1.0V to 2.75V

 Output Voltage:

 Output Current:

1.0A (Max)

 High side FET O-Resistance:

0.4

Ω(Typ)

 Low side FET ON-Resistance:

0.4

Ω(Typ)

 Standby Current:

0.5mA (Typ)

 Operating Temperature Range:

-40°C to +105°C

Packages

W(Typ) x D(Typ) x H(Max)

Typical Application Circuit, Block Diagram

SOP8

5.00mm x 6.20mm x 1.71mm

HSON8

2.90mm x 3.00mm x 0.60mm

VCC

VCC

VDDQ

VDDQ

VTT_IN

VCC

VCC

VCC

SOFT

UVLO

TSD

Reference

Block

Thermal

Protection

Enable

EN

GND

VREF

VTTS

VDDQ

½ x

VTT

VTT

VTT_IN

UVLO

TSD

EN

UVLO

TSD

EN

UVLO

VCC

TSD

EN

UVLO

EN

1

2

4

3

8

7

5

6

Datasheet

Datasheet