January, 1996 TOKO, Inc.

Page 1

TK11821

1-30-96

APPLICATIONS

s Variable Capacitance and PIN Photodiode Bias

s Portable Instrumentation

s Radio Control Systems

s Mobile Radios

s Cellular Telephones

s Cordless Telephones

s Fiberoptic Receivers

s Local Area Network (LAN) Receivers

s Battery Operated Equipment

FEATURES

s Very Low Noise

s Very Small Size

s Few External Components

s Wide Supply Voltage Range (0.9 to 10 V)

s Sinewave Oscillator

s Selectable Output Voltages

TK11821M

Tape/Reel Code

TAPE/REEL CODE

BX:

Bulk/Bag

TL:

Tape Left

MG:

Magazine

ORDERING INFORMATION

DC-DC CONVERTER

TK11821M

BLOCK DIAGRAM

1

2

3

4

OSC

VD

BYPASS

VO

VIN

8

7

6

5

VFB

GND

T1

821

A21

DESCRIPTION

The TK11821 is a low power, low input voltage DC-DC

converter. The device has been optimized for variable

capacitance diode and PIN photodiode bias applications. It

generates 10 Vdc and 24 Vdc output voltages from an input

voltage as low as 0.9 V.

Since the built-in high frequency oscillator generates

sinewaves, the TK11821 produces very low RF interfer-

ence noise. The internal oscillator is capable of operation

at frequencies as high as 6-8 MHz, therefore, interference

filtering is simple and effective. This unique feature makes

the TK11821 ideally suitable for RF and fiber optic receiver

applications.

The device is capable of operation in the 0.9 to 10 V power

supply voltage range.

The output voltage is 24 V when T1 is not connected. When

The TK11821 is available in an 8-pin plastic surface mount

(MFP-8) package. External inductive components are also

available.

VO

T1

GND

BYPASS

V REF

VFB

OSC

Feedback

Control

6

5

2

4

5

7

3

1

VD

VIN