HMC920LP5EWell-suited for power management and control in automotive telematics, Cellular/3G, LTE/WiMAX/4G, broadband, military, and test equipment applications, the HMC920LP5E from Hittite is presented as the first complete Class-A amplifier biasing and monitoring solution.  

The HMC920LP5E is an Active Bias Controller which can be used to bias depletion and enhancement mode amplifiers operating in Class-A regime. This unique IC houses an integrated LDO to regulate the Drain supply of the targeted amplifier and a negative voltage generator for depletion mode devices. The gate voltage of the targeted amplifier is automatically adjusted to keep the quiescent current of the amplifier constant over supply, temperature and threshold drifts.

The control block in the HMC920LP5E manages the correct power-up and power-down sequence of the targeted amplifier to safely turn it on or off. It constantly monitors the quiescent current of the amplifier and generates an alarm if the current exceeds a higher or a lower threshold.

The HMC920LP5E features an Enable pin to quickly turn the targeted amplifier on or off. A Trigger-out signal is generated when the targeted amplifier achieves stable quiescent operation. Using Enable and Trigger-out signals, multiple HMC920LP5E devices can be daisy chained to bias a cascaded amplifier, which makes it possible to enable or disable the cascaded stages in a controlled and sequential manner.

The HMC920LP5E features many built-in safety features to protect both itself and the targeted amplifier from possible unintentional shorts to ground. The HMC920LP5E limits the power dissipation of the device with a power fold-back protection scheme. It constantly checks for failures and shorts to ground at Vdrain, Vnegative, and other important pins, disabling the system if a fault condition arises.

Housed in a compact and RoHS compliant, 5 x 5 mm QFN SMT package, the HMC920LP5E is specified for operation from -40°C to +85°C and is ideal for biasing Hittite’s broad line of amplifiers.
Samples and evaluation PC boards for all SMT packaged products are available from stock and can be ordered via the company’s e-commerce site or via direct purchase order. Released data sheets are available on-line at