Monolithic RF Power Measurement System AD8318 Typical Application Circuit

Published:2011/5/11 4:32:00 Author:Sharon | Keyword: Monolithic, RF power measurement, typical application | From:SeekIC

AD8318 typical application circuit is shown below. AD8318 is designed to measure RF power up to 8GHz. So, to maintain the insulation between the IN + and IN-pin and thefunctional unit circuit is essential. AD8318's positive power supply terminal UPSI and UPSO must take the same voltage. UPSI provides bias voltage for the input circuit andUPSO provides bias voltage for UOUT's low-noise output drive. Besides, there is still some independent public places within AD8318. CMOP is used as the public land of output drivers. All public places should be connected to PCB ground area of low impedance. The permitted supply voltage range is +4.5 ~ 5.5V. C3 ~ C6 is the power decoupling capacitors, which should be close to the power supply pin and ground. AD8318 applies AC coupled and single-ended input mode. When the input signal frequency is 1MHz ~ 8GHz, coupling capacitor (C1, c2) connected to the IN + and IN can use the 0402 1nF surface-mount-type ceramic capacitors, and coupling capacitors should be close to the IN +and IN-pin. External shunt resistor R1 (52.3Ω) is compatible with the IN + terminal, and can provide a 50Ω matching impedance of sufficient bandwidth. AD8318's output voltage can be directly sent to the digital voltmeter (DVM), and can also be sent to A / D converter's microcontroller (μC). To make AD8318 in working condition, ENBL end must be pulled through switch S to get a high electrical level(Us). When ENBL is grounded, AD8318 stays in sleep mode, and power supply current drops to 260μA.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Measuring_and_Test_Circuit/Monolithic_RF_Power_Measurement_System_AD8318_Typical_Application_Circuit.html

Print this Page | Comments | Reading(3)