¡ Semiconductor

MSM7705-01/02/03

16/20

APPLICATION INFORMATION

DOUT Pull-up Resistor

A value of the pull-up resistor for the DOUT pin should be determined depending on frequencies

of BCLK and load capacitance.

If a smaller value is used, there may be some degradation in noise performance, resulting in an

increase in supply current.

Equation to give pull-up resistor

1

————

– 50 ns

Rpull = ———————— (W)

where

50 ns =

Frequency of BCLK

Load capacitance of the PCMOUT pin

(approximately 20 pF for a CMOS or TTL load)

Internal delay of the MSM7705

Condition for Calculation

If data is turned back from DOUT to DIN under the condition the SYNC signal and BCLK signal

rise simultaneously, the data can normally be transferred.

X, RSYNC

BCLK

DOUT

T