Datasheet
50W
50W
PGA
MUX
2
3
1
4.7kW
(2)
18
19
24
1 Fm
10nF
(3)
1MW
100kW
VOP
VOCM
VON
GPIO6
GPIO5
GPIO0
12
8
DGND
VSON
DVDD
SCLK
SDO
SDI
CS
INN2
7
INP2
10
INN1
9
INP1
VSP
+15V
(1)
+5V
+3.3V
6
17 19 15 14 11 12 1315 14 16 13 5
(1)
VSN
-15V
(1)
11
VSOP
4
(1)
3
10
8
9
7
6
1 Fm
1 Fm
1 Fm
RESETPWDN/
DRDY
AINP
REFOUT
AINN
SYNCOUT
START
DIN
DOUT
SCLK
CS
4
5
BYPASS
XTAL2
XTAL1
DGND
DVDD
AVSS
2
16
1
AVDD
20
VREFP
17
VREFN
18
PGA280 ADS1259
Controller
SPI
1 Fm
+
ADS1259
www.ti.com
SBAS424D –JUNE 2009– REVISED AUGUST 2011
3. Optional readback verification of the register data
READ register command: <20h>, <08>
The nine bytes of readback data that follow represent the nine register bytes.
4. Take the START pin high or send the START command to start conversions.
5. Optionally, send the RDATAC command <10h>. This permits reading of conversion data without the need of
the read data command. Otherwise, the read data opcode must be sent to read each conversion result.
6. When the DRDY pin or the DRDY bit goes low, or when DOUT transitions low, read the data.
PGA280 APPLICATION
Figure 65 shows the ADS1259 connected to the PGA280. The PGA280 is a programmable gain, fully-differential
instrumentation amplifier that is ideally suited to drive the ADS1259. The amplifier features ±5V to ±18V supply
input section that accepts wide ranging signal levels and features a +5V output section that matches the
ADS1259 low-voltage inputs. The ADS1259 +2.5V REFOUT drives the PGA280 VOCM pin to level shift the
signal.
The ADS1259 provides a clock output (SYNCOUT) that drives the PGA280 (GPIO6) chopping clock input. An
optional extended CS (ECS) function feature of the PGA280 (GPIO0) allows use of one CS to alternately select
each device for SPI communication. Additionally, the optional BUFA trigger output of the PGA280 (GPIO5) starts
the ADS1259 conversions. The trigger can be delayed to occur after an input multiplexer change. The delay
allows settling of the PGA280 before the ADC conversion begins.
(1) Refer to the PGA280 product data sheet for power-supply bypassing recommendations.
(2) Locate this resistor as close as possible to pin 5 of the ADS1259.
(3) C0G or film capacitor.
Figure 65. PGA280 Driving the ADS1259
Copyright © 2009–2011, Texas Instruments Incorporated 41