Designed for use in analog and digital satellite receivers, this dual low-noise downscaling conversionVoltage regulator(LNBR) is a monolithic linear/switching regulator designed to pass power and interface signals over coaxial cable to an LNB buck converter. The A8297 has a boost switch and compensation circuit integrated into the device, requiring only a few external components. 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.
A8297Designed by leveraging Allegro® Advanced BCD processes for high efficiency. The integrated boost switch is optimized to minimize switching and static losses. To further improve efficiency, voltage drops during the tracking regulator have been minimized.
For DiSEqC™ communication, a tone control pin is provided to gate an internally generated 22kHz tone switch.
The device provides a comprehensive set of fault registers that meet all common criteria, including overcurrent, thermal shutdown, undervoltage, and poor power supply.
The device uses a 2-wire bidirectional serial interface, with I2C™ standard compatible and operates at frequencies up to 400 kHz.
The A8297 is available in a lead-free (Pb) package.
- Integrated boost MOSFETs, current sensing, and compensation
- Continuously delivers up to 550 mA
- Each channel provides up to 700 mA for reconfiguration
- Both channels continuously deliver up to 950 mA of total current
- Both channels provide up to 1,100 mA of total current for reconfiguration
- Adjustable LNB output current limit from 300 to 800 mA
- The boost peak current limit level is set by LNB current limit
- 8-Level Programmable LNB Output Voltage (DAC)
- LNB overcurrent limiter with shutdown timer
- The reliability of the quiescent LNB current limit enables a wide range of loads to be initiated
- Track boost converters to reduce power consumption
- LNB transient time configurable by external capacitors
- The push-pull LNB output stage maintains 13-18 V and 18-13 V transient times, even with high capacitive loads.
- A built-in 22 kHz tone oscillator facilitates DiSEqC™ tone encoding, even when there is no load
- No additional external components are required to produce tones
- Dynamic tone detection of send/receive thresholds for amplitude and frequency
- Extensive protection functions: UVLO, OCP, TSD, CPOK
- ResetInput disable LNB and reset control registers to 0 state to quickly load the 2-wire I2C-compatible ™ interface being loaded
- Small low profile 5 mm × 5 mm, 0.90 mm QFN-28 package