MC13109

7

MOTOROLA ANALOG IC DEVICE DATA

Pre–Amplifier/Expander/Rx Mute/Volume Control (See Figure 4)

The Pre–Amplifier is an inverting rail–to–rail output swing

operational amplifier with the non–inverting input terminal

connected to the internal VB half supply reference. External

resistors and capacitors can be connected to set the gain and

frequency response. The expander analog ground is set to

the half supply reference so the input and output swing

capability will increase as the supply voltage increases. The

volume control can be adjusted through the MPU interface.

The “Rx Audio In” input signal is ac coupled.

(Test Conditions: VCC = 2.6 V, TA = 25°C, fin = 1.0 kHz, Set External Pre–Amplifier R’s for Gain of 1, Volume Control = (0111).)

Characteristic

Condition

Input

Pin

Measure

Pin

Symbol

Min

Typ

Max

Unit

Pre–Amp Open Loop

Gain

–

Rx Audio

In

Pre–Amp

AVOL

–

60

–

dB

Pre–Amp Gain

Bandwidth

–

Rx Audio

In

Pre–Amp

GBW

–

100

–

kHz

Pre–Amp Maximum

Output Swing

RL = 10 kΩ

Rx Audio

In

Pre–Amp

VOmax

–

VCC – 0.3

–

Vpp

Expander 0 dB Gain

Level

Vin = –10 dBV

Rx Audio

In

E Out

G

–3.0

–0.11

3.0

dB

Expander Gain

Tracking

Vin = –20 dBV, Output

Relative to G

V

30 dBV O

Rx Audio

In

E Out

Gt

–21

42

–19.65

39 42

–19

3

dB

g

Vin = –30 dBV, Output

Relative to G

–42

–39.42

–37

Total Harmonic

Distortion

Vin = –10 dBV

Rx Audio

In

E Out

THD

–

0.5

–

%

Maximum Output

Voltage

Increase input voltage

until output voltage

THD = 5%, then

measure output

voltage. RL = 10 kΩ

Rx Audio

In

E Out

VOmax

–

–5.0

–

dBV

Attack Time

Ecap = 1.0 µF,

Rfilt = 20 kΩ

(See Appendix B)

Rx Audio

In

E Out

ta

–

3.0

–

ms

Release Time

Ecap = 1.0 µF,

Rfilt = 20 kΩ

(See Appendix B)

Rx Audio

In

E Out

tr

–

13.5

–

ms

Compressor to

Expander Crosstalk

V (Rx Audio In)

= 0 Vrms,

Vin = –10 dBV

C In

E Out

CT

–

–

–70

dB

Rx Mute

Vin = –10 dBV

No popping

detectable during Rx

Mute transitions

Rx Audio

In

E Out

Me

–

–70

–

dB

Volume Control Range

Programmable through

MPU Interface

–

–

VCrange

–14

–

16

dB

Volume Control Steps

Programmable through

MPU Interface

–

–

VCn

–

16

–

–