(Subject to change without notice)
December 22, 2000
TWO-OUTPUT 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
downconverter via the coaxial cable. Because most satellite receivers have two
antenna ports, the output voltage of the regulator is available at one of two
logic-selectable output terminals (LNBA, LNBB). If the device is in stand-by
mode (EN terminal LOW), both regulator outputs are disabled, allowing the
antenna downconverters to be supplied and controlled by other satellite
CLX 10 BUCK
CNote that the A8284SB (dual in-line package)
and A8284SLB (small-outline IC package) are
Aelectrically identical and share a common
terminal number assignment.
NTABSOLUTE MAXIMUM RATINGS
Supply Voltage, VIN .......................... 47 V
OOutput Current, IO .... Internally Limited
CLogic Input Voltage Range,
receivers sharing the same coaxial cable. Similar single-output devices, with a
bypass function for slave operation in single-dish dual-receiver systems, are the
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
regulators. Logic inputs (VSEL0, VSEL1, and LLC) select the desired output
voltage. A tracking current-mode buck converter provides the linear regulator
input voltage that is set to the output voltage plus typically 0.8 V. This
maintains constant voltage drop across the linear regulators while permitting
adequate voltage range for tone injection.
The device is supplied in a 24-pin plastic DIP with batwing tabs
(A8284SB), or a 24-lead SOIC power-tab package (A8284SLB). In both cases,
the power tab is at ground potential and needs no electrical isolation.
I Complete Interface for Two LNBs Remote Supply and Control
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
VI ................................... -0.5 V to +7 V
Flag Output Voltage, VOLF .................. 7 V
This device incorporates features that have patents pending.
Operating Temperature Range,
TA ............................... -20°C to +85°C
Storage Temperature Range,
TS ............................. -40°C to +150°C
Always order by complete part number, e.g., A8284SLB .