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5.16.1 Digital to Analogue Converter - DAC
LZT 123 7589 R1A
5. SYSTEM CONNECTOR INTERFACE
The DAC is an 8-bit converter. Conversion takes place when an AT
command is sent to the radio device. The radio device sends the resulting
analogue value to the DAC pin.
Tolerance on this internal voltage is ± 5 %
DAC output electrical characteristics are given in the following table.
Parameter
Resolution
Output voltage for code = 0
Output voltage for code = 255
Nominal step size
(7)
Absolute error
Output wide-band noise and clock
feed-through 0 - 1.1 MHz
Power-supply rejection ratio 50 Hz - 10 kHz
Conversion rate ± 0.5 LSB
Output buffer impedance when disabled
Output current source or sink
Current consumption (active)
(6)
Tolerance on this internal voltage is ± 5 %
(7)
Referred to the ideal conversion characteristic.
(8)
See Figure 5.11, page 46
DAC
DGND
DAC
DGND
Limit
8
(2.75
(2.75
(2.75
± 0.5
0.5
40
2 (Load A)
50 (Load B)
50
1
1.0
100 - 200pF
100k
10nF
1nF
1k
Figure 5.11 DAC loads
Units
Bits
V
(6)
x 0.05) ± 0.05
V
(6)
x 0.95) ± 0.05
mV
(6)
x 0.9)/256
mV
mV
dB
ms
(8)
ms
(8)
k
mA
mA
Load A
Load B
rms
46
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