CONTROL-VOLTAGE REGULATOR. 8284 Datasheet

8284 Datasheet PDF, Equivalent


Part Number

8284

Description

TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR

Manufacture

Allegro MicroSystems

Total Page 8 Pages
PDF Download
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8284 Datasheet
8284
ADVANCE INFORMATION
(Subject to change without notice)
December 22, 2000
TWO-OUTPUT LNB SUPPLY AND
CONTROL-VOLTAGE REGULATOR
Intended for analog and digital satellite receivers, the low noise block
A8284SLB
converter regulator (LNBR) is a monolithic linear and switching voltage
regulator designed to provide power and interface signals to the LNB
OSEL 1
24 EXTM
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
OLF 2
23 VINT
logic-selectable output terminals (LNBA, LNBB). If the device is in stand-by
mode (EN terminal LOW), both regulator outputs are disabled, allowing the
VBULK 3
22 PUMPX
antenna downconverters to be supplied and controlled by other satellite
LNBB 4
YNC 5
GND 6
RGND 7
OSENSE 8
TLNBA 99
CLX 10 BUCK
AVIN 11
FTCAP 12
REG.
21 VPUMP
20 CPUMP
19 GND
18 GND
17 ENT
16 EN
15 VSEL0
14 VSEL1
13 LLC
TDwg. PP-072-1A
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
A8283SB/SLB.
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.
FEATURES
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 .

8284 Datasheet
8284
TWO-OUTPUT LNB SUPPLY AND
CONTROL-VOLTAGE REGULATOR
FUNCTIONAL BLOCK DIAGRAM
47 V
MAX
+
RS
VINT
VOLTAGE
REG.
EN
5V
ENT
CHARGE
PUMP
176 kHz
BOOST VOLTAGE
+
÷2
BUCK
CONV.
7V
VREF
352 kHz
OVER-
+ CURRENT
+
150 mV
25 k
800 mV
+
5 k
1
0
÷8 &
WAVESHAPING
22 kHz TONE
TSD
OLF
OVER-CURRENT
5 k
1 k
TCAP
OSEL
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
VSEL0
L
L
L
L
H
H
H
H
L
L
L
L
H
H
H
H
VSEL1
L
L
H
H
L
L
H
H
L
L
H
H
L
L
H
H
LLC
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
VLNBA(typ)
13 V
14 V
18 V
19 V
12 V
13 V
20 V
21 V
Low
Low
Low
Low
Low
Low
Low
Low
VLNBB(typ)
Low
Low
Low
Low
Low
Low
Low
Low
13 V
14 V
18 V
19 V
12 V
13 V
20 V
21 V
Output Voltage Select Table
115 Northeast Cutoff, Box 15036
2 Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2000, Allegro MicroSystems, Inc.
LNBB
EXTM
LNBA
Dwg. FP-051


Features Datasheet pdf 8284 ADVANCE INFORMATION (Subject to cha nge without notice) December 22, 2000 TWO-OUTPUT LNB SUPPLY AND CONTROL-VOLTA GE REGULATOR Intended for analog and di gital satellite receivers, the low nois e block converter regulator (LNBR) is a monolithic linear and switching voltag e regulator designed to provide power a nd interface signals to the LNB downcon verter via the coaxial cable. Because m ost satellite receivers have two antenn a ports, the output voltage of the regu lator is available at one of two logic- selectable output terminals (LNBA, LNBB ). If the device is in stand-by mode (E N terminal LOW), both regulator outputs are disabled, allowing the antenna dow nconverters to be supplied and controll ed by other satellite receivers sharing the same coaxial cable. Similar single -output devices, with a bypass function for slave operation in single-dish dua l-receiver systems, are the A8283SB/SLB . The regulator outputs are set to 12, 13, 18, or 20 V by the VSEL terminals. Additionally, it is poss.
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