User Guide

The HF and HFCM amplifiers include a transient suppression circuitry, which prevents undesired spikes in XEarL

and XEarLC outputs when switching on and off the amplifiers. The HeadInt line is pulled up to 2.7V by the internal

resistor when the accessory is connected. When there is not accessory inserted, the voltage in the HeadInt line

will be <0.8 V caused by internal pull down resistor in the HF line.

Figure 111 External audio connector

Table 9 Audio connector pin assignments

Pin #/ Signal

name

Signal

description

Spectral range Voltage/

Current levels

Max or nominal

serial

impedance

Notes

1/ Charge V Charge DC 0-9V/ 0.85A

2/ GND Charge GND - 0.85A 100mW (PWB+

conn.)

3/ ACI ACI 1kbits/s Digital 0 / 47W Insertion &

removal

detection

2.5-2.78V

4/ Vout DC out DC 2.78V 70 mA 100mW (PWB+

conn.)

200mW

2.5V 90mA

9 / XMIC N Audio in 300-8k 1Vpp &

2.5-2.78VDC

10 / XMIC P Audio in 300-8k 1Vpp &

2.5-2.78VDC

11 / HEAR N Audio out 20-20k 1Vpp 10W

12 / HEAR P Audio out 20-20k 1Vpp 10W

13 / HEAR R N Audio out 20-20k 1Vpp 10W Not conn. in

mono

14 / HEAR R P Audio out 20-20k 1Vpp 10W Not conn. in

mono

RM-1

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Issue 1 Company Confidential Page 9–27