CONTROL-VOLTAGE REGULATOR. 8283 Datasheet
LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR
|Total Page||8 Pages|
(Subject to change without notice)
November 21, 2000
Note that the A8283SB (dual in-line package)
and A8283SLB (small-outline IC package) are
electrically identical and share a common
terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VIN .......................... 47 V
Output Current, IO .... Internally Limited
Logic Input Voltage Range,
VI ................................... -0.5 V to +7 V
Bypass Switch Current,
ISW ........................ Internally Limited
Flag Output Voltage, VOLF .................. 7 V
Operating Temperature Range,
TA ............................... -20°C to +85°C
Storage Temperature Range,
TS ............................. -40°C to +150°C
LNB SUPPLY AND
Intended for analog and digital satellite receivers, the low-noise block
converter regulator (LNBR) is a monolithic linear and switching voltage
regulator designed to provide power and interface signals to the LNB down
converter via the coaxial cable. If the device is in stand-by mode (EN terminal
LOW), the regulator output is disabled, allowing the antenna downconverters to
be supplied or controlled by other satellite receivers sharing the same coaxial
cable. Similar two-output LNB supply and control voltage regulators are the
For slave operation in single-dish dual-receiver systems, the bypass
function is implemented by an electronic switch between the master input
terminal (MI) and the LNB terminal, leaving all LNB power and control
functions to the master receiver. This electronic switch is closed if the device
is powered, EN is HIGH, and OSEL is LOW.
The regulator outputs are set to 12, 13, 18, or 20 V by the VSEL terminals.
Additionally, it is possible to increase the selected voltage by 1 V to compen-
sate for the voltage drop in the coaxial cable (LLC terminal HIGH). The
LNBR combines a tracking switching regulator and low-noise linear regulator.
Logic inputs (VSEL0, VSEL1, and LLC) select the desired output voltage. A
tracking current-mode buck converter provides the linear regulator with an
input voltage that is set to the output voltage plus typically 0.8 V. This main-
tains constant voltage drop across the linear regulator while permitting ad-
equate voltage range for tone injection.
The device is supplied in a 24-pin plastic DIP with batwing tabs
(A8283SB), or a 24-lead SOIC power-tab package (A8283SLB). In both cases,
the power tab is at ground potential and needs no electrical isolation.
I Short-Circuit Protected Bypass Function for Slave Operation
I LNB Selection and Stand-By Function
I Built-In Tone Oscillator Factory Trimmed to 22 kHz, Facilitates
DiSEqC™ (a trademark of EUTELSAT) Encoding
I Full Modulation With No Load
I Tracking Switch-Mode Power Converter for Lowest Dissipation
I Externally Adjustable Short-Circuit Protection
I LNB Short-Circuit Protection and Diagnostics
I Auxiliary Modulation Input
I Cable Length Compensation
I Internal Over-Temperature Protection
This device incorporates features that have patents pending.
Always order by complete part number, e.g., A8283SLB .
LNB SUPPLY AND
FUNCTIONAL BLOCK DIAGRAM
22 kHz TONE
Output Voltage Select Table
115 Northeast Cutoff, Box 15036
2 Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2000, Allegro MicroSystems, Inc.
|Features||Datasheet pdf 8283 PRELIMINARY INFORMATION (Subject to change without notice) November 21, 20 00 LNB SUPPLY AND CONTROL-VOLTAGE REGU LATOR Intended for analog and digital s atellite receivers, the low-noise block converter regulator (LNBR) is a monoli thic linear and switching voltage regul ator designed to provide power and inte rface signals to the LNB down converter via the coaxial cable. If the device i s in stand-by mode (EN terminal LOW), t he regulator output is disabled, allowi ng the antenna downconverters to be sup plied or controlled by other satellite receivers sharing the same coaxial cabl e. Similar two-output LNB supply and co ntrol voltage regulators are the A8284S B/SLB. For slave operation in single-di sh dual-receiver systems, the bypass fu nction is implemented by an electronic switch between the master input termina l (MI) and the LNB terminal, leaving al l LNB power and control functions to th e master receiver. This electronic swit ch is closed if the device is powered, EN is HIGH, and OSEL is .|
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