RF2721 Ver la hoja de datos (PDF) - RF Micro Devices

Número de pieza

componentes Descripción

Fabricante

RF2721

QUADRATURE DEMODULATOR

RF Micro Devices 

RF2721

Preliminary

Pin Function Description

Interface Schematic

10

I OUT

Demodulated baseband I output. The reference DC level of this pin is See pin 8.

set by the voltage of pin 9 (REF IN), which is connected to this pin

through a 5kΩ resistor to the collectors of this push-pull output. This

results in an output impedance of 5kΩ if the REF IN pin is connected to

a low impedance source. The capacitance of the load determines the

maximum baseband frequency. A very low capacitive load may stretch

the 3dB bandwidth over 10MHz. Another way to increase bandwidth is

by connecting a shunt resistor. This will trade gain for bandwidth.

11

GND

Same as pin 2.

12

PD

Power down control. When this pin is "low", all circuits are shut off. A

"low" is typically 0.8V or less at room temperature. When this pin is

"high", all circuits are operating normally.

VCC

PD

13

VCC

Power supply pin. An external 100nF bypass capacitor is recom-

mended if no other bypass capacitor is nearby.

14

IF IN-

Balanced IF input. An input level of 400mVPP gives full output swing; a See pin 1.

level of maximum 250mVPP is recommended for linear operation. This

pin has no internal DC block and an external capacitor of 100nF is

needed if connected to a DC path. If the IF is driven by a single-ended

7

source, connect this pin to an 100nF capacitor to ground.

2-30

Rev A2 010509

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