A8285 Datasheet, PDF (1/17 Pages) Allegro MicroSystems – LNB Supply and Control Voltage Regulator

A8285/A8287
LNB Supply and Control Voltage Regulator
A8285SlB
SOIC
Scale 1:1
SCL 1
SDA 2
IRQ 3
GND 4
VREG 5
VIN 6
EXTM 7
ADD 8
16 VCP
15 BOOST
14 LX
13 GND
12 LNB
11 TOUT
10 TCAP
9 NC
A8287SlB
SOIC
Scale 1:1
SCL 1
SDA 2
IRQ 3
GND 4
GND 5
GND 6
GND 7
VREG 8
VIN 9
EXTM 10
ADD 11
TDO 12
24 VCP
23 BOOST
22 GND
21 GND
20 LX
19 GND
18 GND
17 LNB
16 TOUT
15 TCAP
14 NC
13 TDI
ABSOLUTE MAXIMUM RATINGS
Load Supply Voltage, V_IN....................................16 V
Output Current, I_OUT ..................Internally Limited*
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 the Application Information section
Operating Temperature
Ambient, T_A.......................–20°C to +85°C
Junction, T_J.......................–20°C to +150°C
Storage,T_S .......................–55°C to +150°C
* 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.
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 I²C (Inter-C bus) standard, that operates up to 400 kHz.
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.
FEATURES
LNB selection and standby function
Provides up to 500 mA load current
Two-wire serial I²C interface
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:
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