TK11821
DC-DC CONVERTER
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
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
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
T1 is connected to V
O
, the output voltage is set to 10 V.
The TK11821 is available in an 8-pin plastic surface mount
(MFP-8) package. External inductive components are also
available.
VFB
5
821 21
A
TK11821M
OSC
VD
BYPASS
VO
1
2
3
4
8
7
VFB
GND
6 VIN
5
T1
BLOCK DIAGRAM
OSC
1
VD
2
4
VO
ORDERING INFORMATION
TK11821M
Tape/Reel Code
VIN
6
Feedback
Control
GND
7
5
T1
BYPASS
V REF
3
TAPE/REEL CODE
BX:
TL:
MG:
Bulk/Bag
Tape Left
Magazine
January, 1996 TOKO, Inc.
1-30-96
Page 1
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