The ISL6421A is a single output LNB Supply and Control Voltage Regulator with I2C Interface for Advanced Satellite Set-top Box Designs
The ISL6421A integrates a boost PWM converter and a low‑noise linear regulator to supply and control power for satellite set‑top box LNBs. It communicates via an I²C interface, allowing voltage selection, cable‑length compensation and DiSEqC control.
Key features include selectable 13 V or 18 V outputs, digital over‑current protection, built‑in 22 kHz tone oscillator for DiSEqC encoding, and a QFN package that meets RoHS requirements.
| Selectable Output Voltage | 13 V or 18 V |
|---|---|
| Efficiency | >92 % |
| Typical Output Current | 450 mA |
| Supply Voltage Range | 8 V to 14 V |
| Tone Frequency | 22 kHz |
| Package Type | QFN (32.5 mm × 5 mm) |
It can be set to either 13 V or 18 V via the VSEL bit on the I²C bus.
The over‑current limit is programmable either digitally or with a resistor, and dynamic current limiting is controlled by the DCL bit.
The boost PWM converter operates with greater than 92 % efficiency.
Yes, it has a built‑in 22 kHz oscillator for DiSEqC encoding, controllable via the ENT bit or DSQIN pin.