Datasheet

AVDD
AGND
REFINA
NC
CHA+
CHA-
CHB-
CHB+
NC
REFINB
AGND
AVDD
AVDD
REFOUT
AGND
OUTA
OUTB
CLKOUT
BGND
BVDD
CLKIN
CLKSEL
AGND
AVDD
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
ADS1209
14
13
ADS1209
SBAS491 –FEBRUARY 2010 www.ti.com
PIN CONFIGURATION
PW PACKAGE
TSSOP-24
(TOP VIEW)
PIN DESCRIPTIONS
PIN
NAME NO. I/O
(1)
DESCRIPTION
AVDD 1 P Analog power supply; nominal 5V. Decouple to AGND with a 0.1µF ceramic capacitor.
AGND 2 P Analog ground. Connect to analog ground plane.
REFINA 3 AI Reference voltage input for channel A
NC 4 NC This pin is not internally connected
CHA+ 5 AI Fully differential noninverting analog input channel A
CHA– 6 AI Fully differential inverting analog input channel A
CHB– 7 AI Fully differential inverting analog input channel B
CHB+ 8 AI Fully differential noninverting analog input channel B
NC 9 NC This pin is not internally connected
REFINB 10 AI Reference voltage input for channel B
AGND 11 P Analog ground. Connect to analog ground plane.
AVDD 12 P Analog power supply; nominal 5V. Decouple to AGND with a 0.1µF ceramic capacitor.
AVDD 13 P Analog power supply; nominal 5V. Decouple to AGND with a 0.1µF ceramic capacitor.
AGND 14 P Analog ground. Connect to analog ground plane.
Clock select input. When this pin is low, an external clock source at CLKIN is used. When high, the
CLKSEL 15 DI
internal RC oscillator is used as clock source.
CLKIN 16 DI External clock input. Must be tied to BVDD or BGND, if not used.
BVDD 17 P I/O buffer power supply, nominal: 3V. Decouple to BGND with a 0.1µF ceramic capacitor
BGND 18 P I/O buffer ground. Connect to digital ground plane
CLKOUT 19 DO Bit stream clock output
OUTB 20 DO Bit stream data output of channel B modulator
OUTA 21 DO Bit stream data output of channel A modulator
AGND 22 P Analog ground. Connect to analog ground plane.
REFOUT 23 AO Internal reference voltage output, nominal: 2.5V. Decouple to AGND with a 0.1µF ceramic capacitor.
AVDD 24 P Analog power supply, nominal: 5V. Decouple to AGND with a 0.1µF ceramic capacitor.
(1) AI = analog input; AO = analog output; DI = digital input; DO = digital output; P = power supply; NC = not connected.
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