Datasheet A8283SLB, A8283SB Datasheet (Allegro)

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

continued next page ...

3

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).

OUT

= 24 V,

IN

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Overload Flag Logic Low V

Overload Flag Leakage Current I

Logic Input Voltage V

Logic Input Current I

Supply Current I

OL

OZ

V

IH

IN

I

= 8 mA — 0.28 — V

OL

V

= 5.5 V — <1.0 — µA

OH

IL

IH

V

= 5 V — <1.0 — µA

IH

——0.8V

2.0 — — V

Outputs disabled (EN = L) — 0.5 — mA

ENT = H, IO = 600 mA, VO = 13 V — 382 — mA

Thermal Shutdown Temp. T

Linear Regulator Voltage Drop ∆V

Switching Frequency f

Bypass Switch Current Limit I

Bypass Switch Voltage Drop V

J

BUCK

O

swM

sw

V

– V

BULK

16 • f

O

tone

OSEL = L 630 900 — mA

OSEL = L, I

= 300 mA — 0.15 — V

sw

— 165 — °C

—0.8— V

320 352 384 kHz

(MI to LNB)

4

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

CONTROL-VOLTAGE REGULATOR

FUNCTIONAL DESCRIPTION

8283

LNB SUPPLY AND

The ENT (Tone Enable) terminal activates the internal
tone signal, modulating the dc output with a ±0.3 V, 22
kHz symmetrical waveform. The internal oscillator is
factory-trimmed to provide a tone of 22 kHz ±2 kHz. No
further adjustment is required. The internal oscillator
operates the buck converter at 16 times the tone fre­quency.

Burst coding of the 22 kHz tone can be accomplished
due to the fast response of the ENT input and rapid tone
response. This allows implementation of the DiSEqC™
protocols.

To improve design flexibility and to allow implemen­tation of proposed LNB remote control standards, an
analog modulation input terminal is available (EXTM).
An appropriate dc-blocking capacitor must be used to
couple the modulating signal source to the EXTM termi­nal. If external modulation is not used, the EXTM termi­nal can be left open.

The output linear regulator will sink and source
current. This feature allows full modulation capability
into capacitive loads as high as 0.25 µF.

In operation, the short-circuit protection produces
current fold-back at the input due to the tracking con­verter. If the output is shorted, the linear regulator will
limit the output current to I

. The tracking converter

OM

will maintain a constant voltage drop of 0.8 V across the
linear regulator. This condition results in typically 550
mW dissipation (IOM • 0.8 V). Short-circuit or thermal­shutdown activation will cause the OLF terminal, an open­drain diagnostic output flag, to go LOW.

Thermal resistance:
DIP — R

θJA

SOIC — R

= 40°C/W, R

= 55°C/W, R

θJA

= 6°C/W,

θJT

= 6°C/W.

θJT

The device junction temperature should be kept below
150°C. Thermal shut-down circuitry turns off the device
if junction temperature exceeds +165°C typically.

The programmed output voltage rise and fall times
can be set by an internal 25 kΩ resistor and an external
capacitor located on the TCAP terminal. Although any
value of capacitor is permitted, practical values are
typically 0.001 µF to 0.02 µF. This feature only affects
the turn on and programmed voltage rise and fall times.
Modulation is unaffected by the choice of TCAP. This
terminal can be left open if voltage rise and fall time
control is not required.

Two terminals are dedicated to the over-current
protection/monitoring: SENSE and OLF. The LNB output
is current limited. The short-circuit protection threshold is
set by the value of an external resistor, R
terminals 3 and 8. RS = V

OM(th)/IOM

, between

S

where V

OM(th)

is the
current-limiting threshold voltage and IOM is the desired
current limit value. The minimum recommended value
for RS is 0.17 Ω.

www.allegromicro.com

The products described here are manufactured under one or more

U.S. patents or U.S. patents pending.

Allegro MicroSystems, Inc. reserves the right to make, from time to
time, such departures from the detail specifications as may be
required to permit improvements in the performance, reliability, or
manufacturability of its products. Before placing an order, the user is
cautioned to verify that the information being relied upon is current.

Allegro products are not authorized for use as critical components
in life-support devices or systems without express written approval.

The information included herein is believed to be accurate and
reliable. However, Allegro MicroSystems, Inc. assumes no responsi­bility for its use; nor for any infringement of patents or other rights of
third parties which may result from its use.

5

8283

LNB SUPPLY AND
CONTROL-VOLTAGE REGULATOR

Terminal Configuration

Symbol Terminal Function

OSEL 1 Logic input: selects between LNB on (when high) and

bypass switch closed (when low)

OLF 2 Overload flag output: low when IO > IOM or IO > I

TJ > 165°C, high when IO < IOM and IO < I

VBULK 3 Tracking supply voltage to linear regulators

MIOUT 4 Output voltage from MI (connect to terminal 9)

MI 5 Master input

GND 6, 7 Ground

SENSE 8 Current limit setup resistor

LNB 9 Output voltage to LNB (connect to terminal 4)

LX 10 Inductor drive point

VIN 11 Supply input voltage (minimum, VLNB + 2.5 V)

TCAP 12 Capacitor for setting the rise and fall time of the outputs

LLC 13 Logic input: when high, increases output voltage by 1 V

for line length compensation

VSEL1 14 Logic input: output voltage select

VSEL0 15 Logic input: output voltage select

EN 16 Logic input: when high, enables device

ENT 17 Logic input: when high, enables internal 22 kHz

modulation

SWM

or

SWM

and TJ < 130°C

GND 18, 19 Ground

CPUMP 20 High side of charge-pump capacitor

VPUMP 21 Gate supply voltage for high-side drivers

PUMPX 22 Charge-pump drive

VINT 23 Bypass capacitor for internal voltage reference

EXTM 24 External modulation input

6

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

0.280

0.240

24

NOTE 1

CONTROL-VOLTAGE REGULATOR

A8283SB

Dimensions in Inches

(controlling dimensions)

13

8283

LNB SUPPLY AND

0.014

0.008

0.430

MAX

0.300

BSC

0.210

MAX

7.11

6.10

0.015

MIN

16

0.070

0.045

0.022

0.014

24

1

1.77

1.15

7

NOTE 1

67

0.100

1.280

1.230

BSC

Dimensions in Millimeters

(for reference only)

13

12

32.51

31.24

2.54

BSC

12

0.005

MIN

0.150

0.115

0.13

MIN

0.355

0.204

Dwg. MA-001-25A in

10.92

MAX

7.62

BSC

5.33

MAX

0.39

MIN

0.558

0.356

NOTES: 1. Webbed lead frame. Leads 6, 7, 18, and 19 are internally one piece.

2. Exact body and lead configuration at vendor’s option within limits shown.

3. Lead spacing tolerance is non-cumulative

4. Lead thickness is measured at seating plane or below.

www.allegromicro.com

3.81

2.93

Dwg. MA-001-25A mm

7

8283

24

13

LNB SUPPLY AND
CONTROL-VOLTAGE REGULATOR

A8283SLB

Dimensions in Inches

(for reference only)

0.0125

0.0091

0.2992

0.2914

0.020

0.013

0.0926

0.1043

7.60

7.40

1 2

3

0.6141

0.5985

0.0040

MIN

.

Dimensions in Millimeters

(controlling dimensions)

24 13

0.050

BSC

NOTE 1
NOTE 3

0.491

0.394

0.050

0.016

0° TO 8

Dwg. MA-008-25 in

0.32

0.23

10.65

10.00

1 2

0.51

0.33

3

15.60

15.20

2.65

2.35

0.10

MIN

.

NOTES: 1. Exact body and lead configuration at vendor’s option within limits shown.

2. Lead spacing tolerance is non-cumulative

3. Webbed lead frame. Leads 6, 7, 18, and 19 are internally one piece.

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

8

1.27

BSC

NOTE 1
NOTE 3

1.27

0.40

0° TO 8

Dwg. MA-008-25A mm