AD28MSP02 View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

AD28MSP02

Voiceband Signal Port

Analog Devices 

AD28msp02

To select values for the components shown in Figure 7, use the

following equations:

Gain = RFB

RIN

CI N

=

1

60 π RIN

CFB

=

1

(2 π)(20 × 103 ) RFB

10 kΩ ≤ RFB, RIN ≤ 50 kΩ

150 pF ≤ CFB ≤ 600 pF

Figure 8 shows an example of a typical input circuit configured

for 0 dB gain. The circuit’s diodes are used to prevent the input

signal from exceeding maximum limits.

VCC

330pF

INPUT

10k Ω

SIGNAL

1.0µF

10kΩ

20kΩ

VFBNORM

VINNORM

GNDA

VFBAUX

VINAUX

MUX

VOLTAGE

REFERENCE

AD28msp02

Figure 9 shows a simple circuit providing a differential output

with ac coupling. The capacitor of this circuit (COUT) is

optional; if used, its value can be chosen as follows:

COUT

=1

(60 π) RL

AD28msp02

C OUT

VOUTP

RL

C OUT

VOUT N

Figure 9. Example Circuit for Differential Output

The VOUTP–VOUTN outputs must be used as differential out-

puts; do not use either as a single-ended output. Figure 10

shows an example circuit which can be used to convert the dif-

ferential output to a single-ended output. The circuit uses a

differential-to-single-ended amplifier, the Analog Devices

SSM2141.

+12 V

AD28msp02

0.1 µF

GNDA

Figure 8. Example Analog Input Circuit for 0 dB Gain

Analog Output

The AD28msp02’s differential analog output (VOUTP, VOUTN)

is produced by an on-chip differential amplifier. The differential

amplifier can drive a minimum load of 2 kΩ (RL ≥ 2 kΩ) and

has a maximum differential output voltage swing of ± 3.156 V

peak-to-peak (3.17 dBm0). The differential output can be

ac-coupled directly to a load or dc-coupled to an external

amplifier.

VOUT

7

5

SSM2141

1

4

VOUTP

VOUTN

GNDA

–12 V

0.1 µF

GNDA

Figure 10. Example Circuit for Single-Ended Output

–8–

REV. 0

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