Datasheet

AVDD
DVDD
CH SEL
SCLK
SDO
4 3 2 1
5
6
7
8
9 10 11 12
16
15
14
13
PDEN
NC
GND
REF
REFGND
AIN0P
AIN1P
AIN0GND
AIN1GND
NC
470 pF
C2
470 pF
C1
5 Ω
5 Ω
5 Ω
5 Ω
Input
Signal
Input
Signal
1 F
C3
Common Analog/
Digital Ground Plane
Reference
Input
Analog
Supply
1 F
C4
47 Ω
R1
0.1 F
C5
1 F
C6
Digital
Supply
Digital Signals From Host
ADS7946
U0
CS
ADS7945
ADS7946
www.ti.com SBAS539B –JUNE 2011– REVISED SEPTEMBER 2011
PCB LAYOUT/SCHEMATIC GUIDELINES: ADS7946
The ADS7946 is a mixed-signal device. For maximum performance, proper decoupling, grounding, and proper
termination of digital signals are essential. Figure 92 shows the essential components around the ADC. All
capacitors shown are ceramic. These decoupling capacitors must be placed close to the respective signal pins.
There is a 47 Ω source series termination resistor shown on the SDO signal. This resistor must be placed as
close to pin 15 as possible. Series terminations for SCLK and CS must be placed close to the host.
Figure 92. Recommended ADS7946 ADC Schematic
Copyright © 2011, Texas Instruments Incorporated Submit Documentation Feedback 41
Product Folder Link(s): ADS7945 ADS7946