Sony Ericsson GM47, GM48 manual General Purpose Analogue I/O Ports, Dac, ADC1, ADC2

2.SYSTEM CONNECTOR INTERFACE

2.14General Purpose Analogue I/O Ports

Pin	Signal	Dir	Description
20	DAC	O	Digital to analogue conversion output
26	ADC1	I	Analogue to digital conversion input 1
27	ADC2	I	Analogue to digital conversion input 2
28	ADC3	I	Analogue to digital conversion input 3

The module is able to convert digital to analogue signals and vice versa.

2.14.1 Digital to Analogue Converter - DAC

The DAC is an 8-bit converter. Conversion takes place when an AT command is sent to the module. The module sends the resulting analogue value to the DAC pin.

DAC output electrical characteristics are given in the following table.

Parameter	Limit	Units
Resolution	8	Bits
Output voltage for code = 0	(2.75a x 0.05) ± 0.05	V
Output voltage for code = 255	(2.75a x 0.95) ± 0.05	V
Nominal step size	(2.75a x 0.9)/256	mV
Absolute errorb	≤ ± 0.5	mV
Output wide-band noise and clock	≤0.5	mVrms
feed-through 0-1.1MHz
Power-supply rejection ratio 50Hz - 10kHz	≥40	dB
Conversion rate ± 0.5LSB	≤2 (Load A)c	ms
	≤50 (Load B)c	ms
Output buffer impedance when disabled	≥50	kΩ
Output current source or sink	≥1	mA
Current consumption (active)	≤1.0	mA

a.Tolerance on this internal voltage is ±5%

b.Referred to the ideal conversion characteristic.

c.See Figure 2.9, page 64

63

LZT 123 7263 R1C