ISD5008 Product

4

ANA IN

(Analog Input)

The ANA IN pin is the analog input from the tele-

phone chip set. It can be switched (by the SPI bus)

to the speaker output, the array input or to various

other paths. This pin is designed to accept a nom-

inal 1.11 Vp-p when at its minimum gain (6 dB)

setting. There is additional gain available in 3 dB

steps controlled from the SPI bus, if required, up to

15 dB.

Figure 2:

ANA IN Input Modes

1. Gain from ANA IN to SP+/–

2. Gain from ANA IN to ARRAY IN

3. 0TLP Input is the reference Transmission Level Point that is used for testing. This level is typically 3 dB below clipping.

4. Speaker Out gain set to 1.6 (High). (Differential)

Gain

Setting

Resistor Ratio

(Rb/Ra)

Gain

(dB)

00

63.9/102

0.625

–4.1

01

77.9/88.1

0.88

–1.1

10

92.3/73.8

1.25

1.9

11

106/60

1.77

4.9

Table 4: ANA IN Amplifier Gain Settings

0TLP Input

(3)

CFG0

Array In/Out

Speaker Out

(4)

AIG1

AIG0

6 dB

1.11

0

0

.625

.694

2.22

9 dB

.785

0

1

.883

.694

2.22

12 dB

.555

1

0

1.250

.694

2.22

15 dB

.393

1

1

1.767

.694

2.22