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LEON-G100 / LEON-G200 - System Integration Manual

GSM.G1-HW-09002-G3

Preliminary

System description

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

MIC_BIAS1

: single ended supply to the first microphone and represents the microphone signal input



MIC_GND1

: local ground for the first microphone



Second microphone input:



MIC_BIAS2

: single ended supply to the second microphone and represents the microphone signal input



MIC_GND2

: local ground for the second microphone

For a description of the internal function blocks see Figure 41.

1.10.1.2

Downlink path (speaker outputs)

The RX (downlink) path of the analog audio front-end of the module consists of two speaker outputs available
on the following pins:



First speaker output:



HS_P

: low power single ended audio output. This pin is internally connected to the output of the single

ended audio amplifier of the chipset



Second speaker output:



SPK_N/SPK_P

: high power differential audio output. These two pins are internally connected to the

output of the high power differential audio amplifier of the chipset

See Figure 41 for a description of the internal function blocks.

Warning: excessive sound pressure from headphones can cause hearing loss.

Detailed electrical characteristics of the low power single-ended audio receive path and the high power
differential audio receive path can be found in

LEON-G100 / LEON-G200

Data Sheet

[1].

Table 21 lists the signals related to analog audio functions.

Name

Description

Remarks

HS_DET

Headset detection input

Internal active pull-up to 2.85 V enabled.

HS_P

First speaker output with low power single-ended
analog audio

This audio output is used when audio downlink path is
“Normal earpiece“ or “Mono headset“

SPK_P

Second speaker output with high power differential
analog audio

This audio output is used when audio downlink path is
“Loudspeaker“.

SPK_N

Second speaker output with power differential
analog audio output

This audio output is used when audio downlink path is
“Loudspeaker“.

MIC_BIAS2

Second microphone analog signal input and bias
output

This audio input is used when audio uplink path is set as
“Headset Microphone“. Single ended supply output and
signal input for the second microphone.

MIC_GND2

Second microphone analog reference

Local ground of second microphone. Used for “Headset
microphone” path.

MIC_GND1

First microphone analog reference

Local ground of the first microphone. Used for “Handset
microphone” path

MIC_BIAS1

First microphone analog signal input and bias output

This audio input is used when audio uplink path is set as
“Handset Microphone“. Single ended supply output and
signal input for first microphone.

Table 21: Analog Audio Signal Pins

All audio lines on an Application Board must be routed in pairs, be embedded in GND (have the ground
lines as close as possible to the audio lines), and maintain distance from noisy lines such as VCC and
from components such as switching regulators.

Audio pins ESD sensitivity rating is 1 kV (HBM JESD22-A114F). A higher protection level could be
required if the lines are externally accessible on the application board. A higher protection level can be
achieved mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) on the lines
connected to these pins if they are externally accessible on the application board.

If the audio pins are not used, they can be left floating on the application board.