CS47L35 datasheet(231/300 Pages) CIRRUS

231 / 300 page

DS1085F3

231

CS47L35

5.1 Recommended External Components

5.1.4

Headphone/Earpiece Driver Output Path

The CS47L35 provides a stereo headphone output driver and a mono (differential) earpiece output driver. Note that the

respective output signal path is common to both drivers; only one of these drivers may be enabled at any time. These

outputs are all ground referenced, allowing direct connection to the external loads. There is no requirement for

DC-blocking capacitors.

Under default register conditions, the headphone/earpiece output path is configured for stereo output on HPOUTL and

HPOUTR; this is ideal for stereo headphone loads. In Mono Mode, with the earpiece output driver selected, the output

path is configured for mono (differential) output on EPOUTP and EPOUTN; this is suitable for an earpiece or hearing coil

load.

The headphone output incorporates a common mode, or ground loop, feedback path that provides rejection of

system-related ground noise. The feedback pin must be connected to ground for normal operation of the headphone

outputs. The HPOUT feedback is supported on two pins—the applicable pin is selected using ACCDET_SRC.

The selected feedback pin should be connected to GND as close as possible to the respective headphone jack ground

pin, as shown in Fig. 5-5. In mono (differential) mode, the feedback pins should be connected to the ground plane that is

closest to the earpiece output PCB tracks.

It is recommended to ensure that the electrical characteristics of the PCB traces for each output pair are closely matched.

This is particularly important to matching the two traces of a differential (BTL) output.

Typical headphone and earpiece connections are shown in Fig. 5-5.

Figure 5-5. Headphone and Earpiece Connection

It is common for ESD diodes to be wired to pins that link to external connectors. This provides protection from potentially

harmful ESD effects. In a typical application, ESD diodes are recommended if the headphone path is used for external

headphone or line output.

The HPOUT outputs are ground-referenced, and the respective voltages may swing between +1.8V and –1.8V. The ESD

diode configuration must be carefully chosen.

The recommended ESD diode configuration for these ground-referenced outputs is shown in Fig. 5-6. The back-to-back

arrangement prevents clipping and distortion of the output signal.

Note that similar care is required when connecting the CS47L35 outputs to external circuits that provide input path ESD

protection; the configuration on those input circuits must be correctly designed to accommodate ground-referenced

signals.

Earpiece

The HPOUTFB1 or HPOUTFB2 pin is

selected by the ACCDET_SRC register bit.

HPOUTL

HPOUTR

HPOUTFB1

HPOUTFB2

EPOUTP

EPOUTN

CS47L35

CS47L35 Datasheet(PDF) 231 Page - Cirrus Logic

CS47L35 Datasheet(HTML) 231 Page - Cirrus Logic

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL