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A8298
Single LNB Supply and Control Voltage Regulator
Contact Allegro Marketing for datasheet.
Features
Integrated boost MOSFET, current sensing, and compensation•
Stable with low-profile ceramic boost capacitors•
Higher voltage ratings support increased surge•
Supplies up to 550 mA continuously•
Supplies up to 700 mA for reconfiguration•
Adjustable LNB output current limit from 300 to 800 mA•
Boost peak current limit scales with LNB current limit setting•
8 programmable LNB output voltage (DAC) levels•
LNB overcurrent limiter with shutdown timer•
Tracking boost converter minimizes power dissipation•
LNB transition times configurable by external capacitor•
Push-pull LNB output stage maintains 13→18 V and 18→13 V transition times, even with highly capacitive loads•
Built-in 22 kHz tone oscillator facilitates DiSEqC™ tone encoding, even at no-load•
Tone generation does not require additional external components•
Diagnostic features: PNG, TDET•
Dynamic tone detect amplitude and frequency thresholds•
Extensive protection features: UVLO, OCP, TSD, CPOK•
2-wire I2C-compatible interface•
Description
Intended for analog and digital satellite receivers, this single low noise block converter regulator (LNBR) is a monolithic linear and switching voltage regulator, specifically
designed to provide the power and the interface signals to an LNB down converter via coaxial cable. The A8298 requires few external components, with the boost switch and
compensation circuitry integrated inside of the device. A high switching frequency is chosen to minimize the size of the passive filtering components, further assisting in cost
reduction. The high levels of component integration ensure extremely low noise and ripple figures.
The A8298 has been designed for high efficiency, utilizing the Allegro® advanced BCD process. The integrated boost switch has been optimized to minimize both switching and
static losses. To further enhance efficiency, the voltage drop across the tracking regulator has been minimized.
For DiSEqC™ communications, a tone control pin is provided to gate the internally-generated 22 kHz tone on-and-off.
A comprehensive set of fault registers are provided, which comply with all the common standards, including: overcurrent, thermal shutdown, undervoltage, and power not good.
The device uses a 2-wire bidirectional serial interface, compatible with the I2C™ standard, that operates up to 400 kHz.
The A8298 is supplied in a lead (Pb) free package.
Functional Block Diagram
Part Number Package Type
RoHS
Compliant
Part Composition/
RoHS Data
Temperature Comments Samples/Demo Distributor Stock
A8298SESTR-T 20-lead QFN Yes view data -20 °C to 85 °C new Contact Local Sales Representative
or check distributor stock
All
Check Stock
APEK8298SES-01-T DEMO BOARD No -- -20 °C to 85 °C new Contac
Local Sales Re
resentative
Complete Part Numbers
Allegro's products are no
to be used in life support devices or systems, if a failure of an Allegro
roduct can reasonably be expected to cause the failure of that life
su
or
device or s
stem, or to a
ect the sa
et
or e
ectiveness o
that device or s
stem.
Pa
e 1 of 2Alle
ro
Product
A8298 Sin
le LNB Suppl
and Control Volta
e Re
ulato
10/4/2011htt
://www.alle
romicro.com/en/Products/Part
Numbers/8298
