CS47L85 datasheet(230/370 Pages) CIRRUS

230 / 370 page

CS47L85

230

Rev 4.3

HPOUT1FB1/

MICDET2

MICDET1/

HPOUT1FB2

MICBIASn

* IN1BP, IN2BLP, IN2BR

2.2k

 (+/-2%)

* Note: The Jack plug is shown partially

removed, with the MICDET1 pin in

contact with the headphone load.

* see note

MICDET

Clamp Control

MICD_CLAMP_OVD

MICD_CLAMP_MODE

MICD_CLAMP_STS

MICD_CLAMP_DB

CS47L85

When the MICDET Clamp is active in the configuration shown, the

MICDET1 pin is grounded via the headphone jack ground connection.

* Note that the IN1B or IN2B analogue

mic channel is recommended with the

external accessory detect function

Figure 68 MICDET Clamp circuit

In applications where a large decoupling capacitance is present on the MICBIAS output, the MICDET Clamp function alone

may be unable to discharge the capacitor sufficiently to eliminate pops and clicks associated with jack insertion and removal.

In this case, it may be desirable to use the General Purpose Switch within the CS47L85 to provide isolation from the MICBIAS

output; an example circuit is shown in Figure 69.

The General Purpose Switch is configured using SW1_MODE. This register allows the switch to be disabled, enabled, or

synchronised to the MICDET Clamp status, as described in Table 86.

For jack pop suppression, it is recommended to set SW1_MODE=11. In this case, the switch contacts are open whenever

the MICDET Clamp is active, and the switch contacts are closed whenever the MICDET Clamp is inactive.

Normal accessory functions are supported when the switch contacts (GPSWP and GPSWN) are closed, and the MICDET

Clamp is inactive. Ground clamping of MICDET, and isolation of MICBIAS are achieved when the switch contacts are open,

and the MICDET Clamp is active.

Note that the MICDET Clamp function must also be configured appropriately when using this method of pop suppression

control.

CS47L85 Datasheet(PDF) 230 Page - Cirrus Logic