AD831APZ-REEL7 Analog Devices Inc, AD831APZ-REEL7 Datasheet - Page 8

AD831APZ-REEL7

Manufacturer Part Number

AD831APZ-REEL7

Description

MIXER IC

Manufacturer

Analog Devices Inc

Series

AD831r

Datasheet

1.AD831APZ.pdf (16 pages)

Specifications of AD831APZ-REEL7

Rf Type

HF, VHF

Frequency

500MHz

Number Of Mixers

Gain

0dB

Noise Figure

14dB

Secondary Attributes

Down Converter

Current - Supply

125mA

Voltage - Supply

4.5 V ~ 5.5 V

Package / Case

20-LCC (J-Lead)

Operating Temperature (min)

-40C

Operating Temperature (max)

85C

Operating Temperature Classification

Industrial

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

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The mixer has two open-collector outputs (differential currents) at

pins IFN and IFP.These currents may be used to provide nominal

unity RF to IF gain by connecting a center-tapped transformer

(1:1 turns ratio) to pins IFN and IFP as shown in Figure 2.

Programming the Bias Current

Because the AD831’s RF port is a Class-A circuit, the maximum

RF input is proportional to the bias current. This bias current

may be reduced by connecting a resistor from the BIAS pin to the

positive supply (Figure 3). For normal operation, the BIAS pin is

left unconnected. For lowest power consumption, the BIAS pin is

connected directly to the positive supply. The range of adjustment

is 100 mA for normal operation to 45 mA total current at minimum

power consumption.

AD831

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Figure 2. Connections forTransformer Coupling to

the IF Output

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Figure 3. Programming the Quiescent Current

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Low-Pass Filtering

A simple low-pass filter may be added between the mixer and

the output amplifier by shunting the internal resistive loads

(an equivalent resistance of about 14  with a tolerance of 20%)

with external capacitors; these attenuate the sum component in

a downconversion application (Figure 4). The corner frequency

of this one-pole low-pass filter (f = (2  RC

about an octave above the difference frequency IF. Thus, for a

70 MHz IF, a –3 dB frequency of 140 MHz might be chosen,

using C

standard value.

Using the Output Amplifier

The AD831’s output amplifier converts the mixer core’s differential

current output into a single-ended voltage and provides an output

as high as ±1 V peak into a 50 V load (+10 dBm). For unity gain

operation (Figure 5), the inputs AN and AP connect to the open-

collector outputs of the mixer’s core and OUT connects to VFB.

Figure 4. Low-Pass Filtering Using External Capacitors

Figure 5. Output Amplifier Connected for Unity

Gain Operation

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AD831APZ-REEL7 Analog Devices Inc, AD831APZ-REEL7 Datasheet - Page 8

AD831APZ-REEL7

Specifications of AD831APZ-REEL7

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