A8285/A8287

LNB Supply and Control Voltage Regulator

Intended for analog and digital satellite receivers, the LNB (low noise

block) converter regulator is a monolithic linear and switching voltage

regulator, specifically designed to provide power and interface signals

to an LNB downconverter, via coaxial cable.

The device uses a 2-wire bidirectional serial interface, compatible with

The A8285 is supplied in a 16-lead plastic power SOIC with internally

fused leads for thermal dissipation. The A8287 is supplied in a 24-lead

plastic power SOIC with internally fused leads. Both devices are also

available in lead (Pb) free versions, with 100% matte tine leadframe

plating.

LNB selection and standby function

Provides up to 500 mA load current

Built-in tone oscillator, factory-trimmed to 22 kHz; facilitates

DiSEqC™ 2.0 encoding

Auxiliary modulation input

22 kHz tone detector facilitates DiSEqC™ decoding (A8287 only)

Tracking switch-mode power converter for lowest dissipation

LNB overcurrent protection and diagnostics

Internal overtemperature protection

LNB voltages (16 possible levels) compatible with all common

standards

Use the following complete part numbers when ordering:

ABSOLUTE MAXIMUM RATINGS

8

ADD

4

GND

7

EXTM

3

IRQ

6

VIN

2

SDA

5

VREG

9

NC

13

GND

10

TCAP

14

LX

11

TOUT

15

BOOST

12

LNB

16

VCP

1

SCL

A8287SlB

SOIC

Part Number

Pb-free

Package

Description

A8285SLB

–

16-pin SOIC

Tone detect not provided

A8285SLB-T

Yes

16-pin SOIC

Tone detect not provided

A8287SLB

–

24-pin SOIC

All features

A8287SLB-T

Yes

24-pin SOIC

All features

Load Supply Voltage, V

Output Current, I

Output Voltage

LNB, BOOST .....................–0.3 V to 28 V

TOUT ................................. –0.3 V to 22 V

Logic Input

EXTM ...................................–0.3 V to 5 V

Other .................................... –0.3 V to 7 V

Logic Output ........................................ –0.3 V to 7 V

Package Power Dissipation ………..See power dissi-

pation information in theApplication Information section

Operating Temperature

Ambient, T

Junction, T

Storage,T

* Output current rating may be limited by duty cycle,

ambient temperature, and heat sinking. Under any

set of conditions, do not exceed the specified current

rating or a junction temperature of +150°C.

13

TDI

14

NC

TCAP

15

16

TOUT

17

LNB

21

GND

18

GND

22

GND

19

GND

23

BOOST

20

LX

24

VCP

12

TDO

11

ADD

10

EXTM

9

VIN

8

VREG

4

GND

7

GND

3

IRQ

6

GND

2

SDA

5

GND

1

SCL

A8285SlB

SOIC

FEATURES

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