Datasheet

System Monitors
Temperature
Diode
VREFP
VREFN
VREFP1/4
VREFN1/4
VREFP0/4
VREFN0/4
AVDD/4
AVSS/4
DVDD/4
DGND/4
ADS1148 Only
ADS1147/8 Only
VBIAS
AIN0
AIN1
VBIAS
AIN2
VBIAS
AIN3
VBIAS
AIN4
VBIAS
AIN5
VBIAS
AIN6
VBIAS
AIN7
AVDD
IDAC1
IDAC2
AVDD
VBIAS
PGA
AIN
P
AVSS
AVDD
Burnout Current Source
(0.5 A, 2 A, 10m m mA)
Burnout Current Source
(0.5 A, 2 A, 10m m mA)
AIN
N
To
ADC
AVSS
AVSS
AVSS
AVSS
AVSS
AVSS
AVSS
AVSS
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD AVDD
ADS1146
ADS1147
ADS1148
SBAS453F –JULY 2009–REVISED APRIL 2012 www.ti.com
ADC INPUT AND MULTIPLEXER Any analog input pin can be selected as the positive
input or negative input through the MUX0 register.
The ADS1146/7/8 ADC measures the input signal
The ADS1146/7/8 have a true fully differential mode,
through the onboard PGA. All analog inputs are
meaning that the input signal range can be from
connected to the internal AIN
P
or AIN
N
analog inputs
–2.5V to +2.5V (when AVDD = 2.5V and
through the analog multiplexer. A block diagram of
AVSS = –2.5V).
the analog input multiplexer is shown in Figure 19.
Through the input multiplexer, the ambient
The input multiplexer connects to eight (ADS1148),
temperature (internal temperature sensor), AVDD,
four (ADS1147), or two (ADS1146) analog inputs that
DVDD, and external reference can all be selected for
can be configured as single-ended inputs, differential
measurement. Refer to the System Monitor section
inputs, or in a combination of single-ended and
for details.
differential inputs. The multiplexer also allows the on-
chip excitation current and/or bias voltage to be On the ADS1147 and ADS1148, the analog inputs
selected to a specific channel. can also be configured as general-purpose
inputs/outputs (GPIOs). See the General-Purpose
Digital I/O section for more details.
Figure 19. Analog Input Multiplexer Circuit
18 Submit Documentation Feedback Copyright © 2009–2012, Texas Instruments Incorporated
Product Folder Link(s): ADS1146 ADS1147 ADS1148