User's Manual

GE865 Hardware User Guide

1vv0300799 Rev.6 - 04/06/09

10 OUTPUT LINES (Speaker)

10.1 Short description

The Telit GE865 provides one audio paths in receive section.

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the “Ear” lines EPN1 and EPP1 are the Differential Line-Out Drivers ; they can drive an external

amplifier or directly a 16 Ω earpiece at –12dBFS (*) ;

(*) FS : acronym of Full Scale. It is equal to 0dB, the maximum Hardware Analog Receive Gain of

BaseBand Chip.

The output is a B.T.L. type (Bridged Tie Load) and the OEM circuitry shall be designed bridged to

reduce the common mode noise typically generated on the ground plane and to get the maximum

power output from the device; however also a single ended circuitry can be designed for particular

OEM application needs.

10.2 Output Lines Characteristics

“Ear” Differential Line-out Drivers Path

• line coupling: DC

• line type: bridged

• output load resistance : ≥ 14 Ω

• internal output resistance: 4 Ω (typical)

• signal bandwidth: 150 - 4000 Hz @ -3 dB

• max. differential output voltage 1310 mV

rms

(typ, open circuit)

• differential output voltage 328mVrms /16 Ω @ -12dBFS

• SW volume level step - 2 dB

• number of SW volume steps 10

For more detailed information about audio please refer to the Audio Settings Application Note

80000NT10007a