11/16

・

VTT

A DDR memory termination output pin.

BD3533/31/32 has a sink/source current capability of ±1.0A/±1.5A/±3.0A

respectively. The output voltage tracks the voltage divided in half at VDDQ pin. VTT output is turned to OFF when VCC

UVLO or thermal shutdown protector is activated with EN pin level turned to “Low”. Do not fail to connect a capacitor to

VTT output pin for a loop gain phase compensation and a reduction in output voltage variation in the event of sudden change

in load. Insufficient capacitance may cause an oscillation. High ESR (Equivalent Series Resistance) of the capacitor may

result in increase in output voltage variation in the event of sudden change in load. It is recommended to use a 220 μF

functional polymer capacitor (OS-CON, POS-CAP, NEO-CAP), though it depends on ambient temperature and other

conditions. A low ESR ceramic capacitor may reduce a loop gain phase margin and may cause an oscillation, which may

be improved by connecting a resistor in series with the capacitor.

・

EN

With an input of 2.3 volts or higher, the level at EN pin turns to “High” to provide VTT output. If the input is lowered to 0.8

volts or less, the level at EN pin turns to “Low” and VTT status turns to Hi-Z. But if VCC and VDDQ are established, VREF

output is maintained.

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Evaluation Board

Part No

Value

Company

Parts Name

Part No

Value

Company

Parts Name

U1

-

ROHM

BD3533F

C4

-

-

-

R1

-

-

-

C5

10uF

KYOCERA

CM21B106M06A

R4

220Ω

ROHM

MCR032200

C6

-

-

-

J1

0Ω

-

-

C7

-

-

-

J2

0Ω

-

-

C8

-

-

-

C1

-

-

-

C9

2.2uF

KYOCERA

CM105B225K06A

C2

10uF

KYOCERA CM21B106M06A

C10

220uF

SANYO

2R5TPE220MF

C3

1uF

KYOCERA CM105B105K06A

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BD3533F Evaluation Board Application Components

Versions for MSOP8 and HQFN20V packages are also available.

In addition, BD3533F/FVM/EKN(1A), BD3531F(1.5A), and BD3532F/EFV/KN(3A) are available

.

Silk Screen

TOP Layer

Bottom Layer

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BD3533F Evaluation Board Circuit

C5,C6

GND

BD3533F

VREF

EN

VCC

VDDQ

VTT_IN

VTTS

VTT

GND

VCC

SW1

J2

R4

C9

J1

C3,C4

C7 C8 C10

C2

C1

R1

2

7

5

6

1

8

3

4

U1

VTT_IN

VCC

VTT

VREF

VDDQ

EN

VTTS

GND

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BD3533F（SOP8） Evaluation Board Layout