Siemens EF 88H Series Manual de usuario descargar pdf (Pagina 94)

Device Specification

Semiconductor Group 7-32

A/D Converter

In the SAB 80C517A a new high performance / high-speed 12-channel 10-bit A/D-Converter is

implemented. Its successive approximation technique provides 7

µs con-version time (f

OSC

= 16

MHz). The conversion principle is upward compatible to the one used in the SAB 80C517. The

main functional blocks are shown in figure 4.

The comparator is a fully differential comparator for a high power supply rejection ratio and very

low offset voltages. The capacitor network is binary weighted providing genuine 10-bit

resolution.

The table below shows the sample time T

and the conversion time T

, which are dependend

on f

OSC

and a new prescaler (see also Bit ADCL in SFR ADCON 1).

OSC

[MHz] Prescaler f

ADC

[MHz] Sample Time

[µs]

Conversion Time

(incl. sample time)

[µs]

12 ÷ 8 1.5 2.67 9.33

÷ 16 0.75 5.33 18.66

16 ÷ 8 2.0 2.0 7.0

÷ 16 1.0 4.0 14.0

18 ÷ 8 – – –

÷ 16 1.125 3.55 12.4

1 2 ... 89 90 91 92 93 94 95 96 97 98 99 ... 136 137

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Siemens EF 88H Series Manual de usuario Pagina 94