DAC8541 Datasheet, PDF (18/21 Pages) Texas Instruments – 16-BIT SINGLE CHANNEL, PARALLEL INPUT DIGITAL-TO-ANALOG CONVERTER WITH RAIL VOLTAGE OUTPUT

DAC8541
SLAS353 − DECEMBER 2001
TMS320C5402
D[15:0]
A[23:0]
IOSTRB
R/W
XF(I/O)
APPLICATION INFORMATION
16 Bits
DAC8541
D[15:0]
AVDD
0.1 µF
EN
Address
Decoder
CS
R/W
LDAC
DVDD
0.1 µF
VOUTSENSE
VOUT
VREFL
DGND
VREFH
AGND
0.1 µF
(Other Connections Omitted for Clarity)
10 µF
AVDD
10 µF
DVDD
VOUT
VREF
1 to 10 µF
Figure 33. DAC8541 to TMS320 DSP
bipolar operation using the DAC8541
The DAC8541 has been designed for single-supply operation but a bipolar output range is also possible using
the circuit shown in Figure 34. The circuit allows the DAC8541 to achieve an analog output range of ±5 V.
Rail-to-rail operation at the amplifier output is achievable using an OPA703 as the output amplifier.
Setting BTC/USB = 1, sets the DAC into binary 2s complement I/O format for the bipolar V_OUT configuration.
When operated with BTC/USB set high, the output voltage for any input code can be calculated as follows:
ƪ ǒ Ǔ ǒ Ǔ ǒ Ǔƫ VOUT + VREFH
D
65536
R1 ) R2
R1
* VREFH
R2
R1
where D represents the input code in decimal, unipolar straight binary (0–65535) and V_REFL = AGND.
With V_REFH = 5 V, R₁ = R₂ = 10 kΩ:
ǒ Ǔ _{VOUT +}
10 D
65536
*5V
This is an output voltage range of ±5 V with 8000h corresponding to a –5 V output and 7FFFh corresponding
to a 5 V output. Bipolar zero is given by 0000h applied to the DAC.
R2 = 10 kΩ
5V
10 µF ^{0.1 µF}
R1 = 10 kΩ
VREFH
VOUT
DAC8541
VOUTSense
VREFL
(Other Pins Omitted for Clarity)
5V
−
+
±5 V
OPA703
−5 V
Figure 34. Bipolar Operation With the DAC8541
18
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