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

19

HMC992LP5E

v03.1013

IF AUTOMATIC GAIN CONTROLLER

(IF-AGC), 50 - 800 MHz

AGC Set point Interface VSET

In closed loop AGC operation the output power level of the HMC992LP5E is controlled by the VSET pin. An input volt-

age between 0.2V and 1.2V should be applied to the VSET input pin to control the output power level. The VSET vs.

the output power characteristic is shown in Figure 6a and Figure 6b for different input power levels and different coupler

ratios used. The slope of the gain vs. VSET characteristic is 57dB/V and it is independent of the coupler ratio used.

In closed loop operation the HMC992LP5E is able to automatically adjust the RF gain over a gain adjustment range

of up to 46 dB at 100 MHz. The HMC992LP5E’s output dynamic range is a function of both input power level and the

coupler ratio used to close the AGC loop. The combined effect of the input power and coupler ratio on the output power

dynamic range is presented in Figures 6a and 6b.

For high input power levels, the maximum level of output dynamic range is limited by the Psat of the VGA or the high-

est detectable power level by the log detector. To eliminate any limitations that can arise due to highest detectable log

detector, a high enough coupler ratio should be chosen to translate the maximum VGA output power level to a value

lower than the highest detectable log detector power level.

Figure 6a: Output Power vs. VSET over Input Power, 2 attenuators @ 300 MHz.

-40

-30

-20

-10

0

10

20

30

0.2

0.4

0.6

0.8

1

1.2

Input Power = -25 dBm

Input Power = -20 dBm

Input Power = -15 dBm

VSET (V)

20 dB coupler is used

-40

-30

-20

-10

0

10

20

30

0.2

0.4

0.6

0.8

1

1.2

Coupler= -10 dBm

Coupler= -20 dBm

Coupler= -30 dBm

VSET (V)

Input Power = -20 dBm

Figure 6b: Output Power vs. VSET over coupler ratio, 2 attenuators @ 300 MHz.

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