Designed for use in analog and digital satellite receivers, this single low-noise downconversion is convertedVoltage regulator(LNBR) is a monolithic linear/switching regulator designed to pass power and interface signals over coaxial cable to an LNB buck converter. The A8290 requires few external components and has a boost switch and compensation circuitry integrated into the device. A higher switching frequency is chosen to minimize the size of the passive filter element, further reducing costs. The high level of component integration ensures extremely low noise and pulsation patterns.
The A8290 is designed to achieve high efficiency by leveraging Allegro's® advanced BCD processes. The integrated boost switch is optimized to minimize switching and static losses. To further improve efficiency, minimize the voltage drop during the tracking regulator.
The A8290 has an integrated tone detection feature that fully supports both DiSEqC™ communications. Several modes are available to generate a tone signal using an internal or external clock source throughout the process until there is no load. DiSEqC™ filter bypass switches have been integrated to minimize output impedance during tone production.
The device provides a comprehensive set of fault registers that meet all common criteria, including: overcurrent, thermal shutdown, undervoltage, cable disconnect, power failure, and tone detection.
The device uses a 2-wire bidirectional serial interface, with I2C™ standard compatible and operating frequency up to 400 kHz.
The A8290 is available in a lead-free 28-pin MLP/QFN package.
- 2-wire serial I2C-compatible™ interfaces: control (write) and status (read)
- LNB voltages (16 programmable levels) are compatible with all common standards
- Lowest dissipation tracking switch-mode power converter
- Integrated converter switching and current sensing
- Provides continuous load currents up to 700 mA
- Typical 900 mA output current limit with 48 ms timer
- Quiescent current limiting circuitry allows full current at start-up, 13→18 V output conversion, and a wide load range for reliable start-up
- The push-pull output stage minimizes 13→18 V and 18→13 V output conversion times for high capacitive loads
- The rise/fall time is adjustable by an external timing capacitor
- Built-in tone oscillator, factory calibrated to 22 kHz, helps DiSEqC™ tone encoding, even when there is no load
- Via I2The C™ data bit and/or external pin enable four 22 kHz tone generation methods
- Filter bypass MOSFETs minimize losses during tone transmission
- The 22 kHz tone detector helps with DiSEqC™ 2.0 decoding
- SWM (Single Wire Multiple Switch) operates at 700 mAhoutput The voltage is 19 to 21 V dc
- Output voltage level, input supply UVLO, and DiSEqC™ tone output diagnostics
- Auxiliary modulation input
- With timer LNB overcurrent
- Cable disconnect diagnostics