For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824

Phone: 978-250-3343

Fax: 978-250-3373

Order On-line at www.hittite.com

Application Support: Phone: 978-250-3343 or apps@hittite.com

18

HMC992LP5E

v03.1013

IF AUTOMATIC GAIN CONTROLLER

(IF-AGC), 50 - 800 MHz

AGC Operation

The HMC992LP5E can be configured as an AGC amplifier by using VGA core and the built in log detector. An example

for AGC amplifier configuration of the HMC992LP5E is depicted in below figure.

Figure 5: The HMC992LP5E’s AGC configuration with 2 attenuators.

In AGC amplifier configuration, the input signal is amplified by the HMC992LP5E’s VGA.The output of the HMC992LP5E’s

VGA core is fed back to the input of the HMC992LP5E’s log detector (RFDETIN) through an external coupler or attenu-

ator to drop the maximum and minimum output level of the HMC992LP5E’s VGA to within the dynamic range of the

HMC992LP5E’s log detector. The HMC992LP5E’s log detector produces a voltage at the output of the log detector

(DETOUT) proportional to the output power level of the HMC992LP5E’s VGA. The high impedance output pin DETOUT

is connected to the gain control pin VCTRL of VGA to form the AGC loop. The VSET pin is the constant output power set

point of the AGC amplifier. As a result of negative feedback, the gain of the VGA is automatically adjusted to maintain a

constant signal power level at the output of AGC amplifier. The output signal power level is determined by the AGC set

point VSET, regardless of the input signal variation.

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice. No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarks and registered trademarks are the property of their respective owners.

For price, delivery, and to place orders: Analog Devices, Inc.,

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106

Phone: 781-329-4700 • Order online at www.analog.com

Application Support: Phone: 1-800-ANALOG-D