ADS8254 Datasheet, PDF (26/36 Pages) Texas Instruments – 16-BIT, 1-MSPS, PSEUDO-BIPOLAR DIFFERENTIAL SAR ADC WITH ON-CHIP ADC DRIVER (OPA) AND 4-CHANNEL DIFFERENTIAL MULTIPLEXER

ADS8254
SLAS643 – MARCH 2009................................................................................................................................................................................................... www.ti.com
From BUF-REF o/p of ADC
(Use external buffer if current drawn by
resistor network exceeds current output
specification of reference buffer)
R
R
R
R
C
C
CHnP
CHnM
±2* Ref True Bipolar,
Diff Signals
Note: Value of R depends on signal BW Use R = 1.2 kW for signal BW <= 10 kHz.
Choose C as per signal BW, 3 dB BW (filt) = RC/2
Figure 70. Bipolar Input Signals to Unipolar Differential Signals Conversion
MICROCONTROLLER INTERFACING
ADS8254 to 8-Bit Microcontroller Interface
Figure 71 shows a parallel interface between the ADS8254 and a typical microcontroller using an 8-bit data bus.
The BUSY signal is used as a falling edge interrupt to the microcontroller.
Analog 5 V
0.1 mF
AGND
10 mF
0.1 mF
Ext Ref Input
Analog Input
Micro
Controller
GPIO
GPIO
GPIO
RD
AD[7:0]
Data Bus D[17:0]
CS
BYTE
ADS8254
BDGND
CONVST
RD
DB[17:10]
+VBD
Digital 3 V
0.1 mF
BDGND
Figure 71. ADS8254 Application Circuitry
26
Submit Documentation Feedback
Product Folder Link(s) :ADS8254
Copyright © 2009, Texas Instruments Incorporated