Allegro A8283SLB, A8283SB Datasheet

Data Sheet

PRELIMINARY INFORMATION

(Subject to change without notice)

November 21, 2000

A8283SLB

OSEL

1

OLF

2

VBULK

MIOUT

SENSE

3

4

MI

5

GND

6

GND

7

8

9

LNB

9

LX

VIN

TCAP

Note that the A8283SB (dual in-line package)
and A8283SLB (small-outline IC package) are
electrically identical and share a common
terminal number assignment.

BUCK

10

11

12

REG.

CHARGE

VOLTAGE

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, V

Operating Temperature Range,

TA............................... -20°C to +85°C

Storage Temperature Range,

TS............................. -40°C to +150°C

.................. 7 V

OLF

EXTM

24

VINT

23

PUMPX

22

VPUMP

21

PUMP

CPUMP

20

GND

19

18

GND

ENT

17

EN

16

VSEL0

15

VSEL1

14

CONTROL

LLC

13

Dwg. PP-072A

8283

LNB SUPPLY AND

CONTROL-VOLTAGE REGULATOR

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
A8284SB/SLB.

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 compen­sate 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 main­tains constant voltage drop across the linear regulator while permitting ad­equate 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.

FEATURES

■ Short-Circuit Protected Bypass Function for Slave Operation

■ LNB Selection and Stand-By Function

■ Built-In Tone Oscillator Factory Trimmed to 22 kHz, Facilitates

DiSEqC™ (a trademark of EUTELSAT) Encoding

■ Full Modulation With No Load

■ Tracking Switch-Mode Power Converter for Lowest Dissipation

■ Externally Adjustable Short-Circuit Protection

■ LNB Short-Circuit Protection and Diagnostics

■ Auxiliary Modulation Input

■ Cable Length Compensation

■ Internal Over-Temperature Protection

This device incorporates features that have patents pending.

Always order by complete part number, e.g., A8283SLB .

27448

8283

LNB SUPPLY AND
CONTROL-VOLTAGE REGULATOR

FUNCTIONAL BLOCK DIAGRAM

VINT

ENT

OLF

VBULK

150 mV

RS

SENSE

MI

MIOUT

LNB

EXTM

Dwg. FP-051-1

47 V
MAX

VPUMP

CHARGE

TSD

PUMP

CPUMP

176 kHz

OVER­CURRENT

PUMPX

VOLTAGE

REG.

EN

5 V

VIN

BOOST

VOLTAGE

–

+

÷2

÷8

&

WAVESHAPING

7 V

0

1

352 kHz

22 kHz TONE

OSEL

BUCK

CONV.

VREF

VSEL0

VSEL1

LX

–

OVER-

+

CURRENT

800 mV

TCAP

–

+

25 kΩ

LLC

–

+

1 kΩ

+

+

–

5 kΩ

5 kΩ

Output Voltage Select Table

VSEL0 VSEL1 LLC V

LLL13 V
L L H 14 V
LHL18 V

L H H 19 V
H L L 12 V
H L H 13 V
H H L 20 V
HHH21 V

2

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
Copyright © 2000, Allegro MicroSystems, Inc.

LNB(typ)

8283

LNB SUPPLY AND

CONTROL-VOLTAGE REGULATOR

ELECTRICAL CHARACTERISTICS at TA = 25°C, ENT = L, EN = H, OSEL = H, LLC = L, V
I

= 50 mA (unless otherwise noted).

O

= 24 V,

IN

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Supply Voltage V

Output Voltage V

Line Regulation ∆V

IN

O

O

IO = 600 mA, VSEL0 = L, VSEL1 = L, LLC = L

IO = 600 mA, VSEL0 = L, VSEL1 = L, LLC = L

IO = 600 mA, VSEL0 = L, VSEL1 = L, LLC = H

IO = 600 mA, VSEL0 = L, VSEL1 = H, LLC = L

IO = 600 mA, VSEL0 = L, VSEL1 = H, LLC = H

IO = 600 mA, VSEL0 = H, VSEL1 = L, LLC = L

IO = 600 mA, VSEL0 = H, VSEL1 = L, LLC = H

IO = 600 mA, VSEL0 = H, VSEL1 = H, LLC = L

IO = 600 mA, VSEL0 = H, VSEL1 = H, LLC = H

—

3.3 + ∆V

BUCK

47 V

12.5 13 13.5 V

13.4 14 14.6 V

17.3 18 18.7 V

18.2 19 19.8 V

11.5 12 12.5 V

12.5 13 13.5 V

19.2 20 20.8 V

20.2 21 21.8 V

VO = 13 V, VI = 16 to 40 V — 4.0 40 mV

VO = 18 V, VI = 21 to 40 V — 4.0 40 mV

Load Regulation ∆V

Current-Limiting Threshold V

Tone Frequency f

Tone Amplitude V

OM(th)

tone

tone(PP)

Tone Duty Cycle dc

Tone Rise or Fall Time tr, t

External Modulation Gain G

External Modulation V

mod

mod(PP)

O

tone

f

VO = 13 or 18 V, IO = 50 to 600 mA — 80 180 mV

125 135 145 mV

ENT = H 20 22 24 kHz

ENT = H 550 680 800 mV

ENT = H 40 50 60 %

ENT = H 5.0 10 15 µs

∆VO/∆V

, f = 10 Hz to 40 kHz — 5.0 — V/V

mod

AC coupling — — 160 mV

Input Voltage

External Modulation Z
Impedance

www.allegromicro.com

mod

f = 10 Hz to 40 kHz — 5.0 — kΩ

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