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PGA308
PGA308
Fault
Monitor
Front-End
GainSelect
V
IN1
5
6
3
V
REF
V
S
V
IN2
Auto-Zero
PGA
7-Bit+Sign
DAC
PGA308
16-Bit
DAC
Output
Amplifier
NOTE: (1)Ref=V orV selectable.
REF S
V
EXC
V
REF
V
FB
4 10 1
2
8
7
9
V
OUT
V
SJ
GND
Input
Mux
Scale
Limit
1W
DigitalInterface
(One-Wire)
OTP
(7Banks)
RAM
CoarseOffset
V
REF
V
REF
16-Bit
DAC
Ref
(1)
Ref
(1)
FineOffset
OutputGain
FineGain
Output
Gain
Select
D
OUT
Select
3-Bit
DAC
Underscale
3-Bit
DAC
Overscale
D /V
OUT CLAMP
Bridge
Sensor
PGA308
www.ti.com
SBOS440B –JULY 2008–REVISED DECEMBER 2010
Single-Supply, Auto-Zero Sensor Amplifier
with Programmable Gain and Offset
Check for Samples: PGA308
1
FEATURES
DESCRIPTION
2
• Digital Calibration for Bridge Sensors
The PGA308 is a programmable analog sensor signal
conditioner. The analog signal path amplifies the
• Offset Select: Coarse and Fine
sensor signal and provides digital calibration for offset
• Gain Select: Coarse and Fine
and gain. Calibration is done via the 1W pin, a digital
• Bridge Fault Monitor
One-Wire, UART-compatible interface. For
• Input Mux for Lead Swap three-terminal sensor modules, 1W may be
connected to V
OUT
and the assembly programmed
• Over/Under Scale Limits
through the V
OUT
pin. Gain and offset calibration
• D
OUT
/ V
OUT
Clamp Function
parameters are stored onboard in seven banks of
• Seven Banks OTP Memory
one-time programmable (OTP) memory. The
power-on reset (POR) OTP bank may be
• One-Wire Digital UART Interface
programmed a total of four times.
• Operating Voltage: +2.7V to +5.5V
The all-analog signal path contains a 2×2 input
• Temperature Range: –40°C to +125°C
multiplexer (mux) to allow electronic sensor lead
• MSOP-10 and 3mm × 4mm DFN-10 Packages
swapping, a coarse offset adjust, an auto-zero
programmable gain instrumentation amplifier (PGA),
APPLICATIONS
a fine gain adjust, a fine offset adjust, and a
programmable gain output amplifier. Fault monitor
• Bridge Sensors
circuitry detects and signals sensor burnout,
• Remote 4-20mA Transmitters
overload, and system fault conditions.
• Strain, Load, Weigh Scales
Over/under-scale limits provide additional means for
• Automotive Sensors
system level diagnostics. The dual-use D
OUT
/V
CLAMP
pin can be used as a programmable digital output or
EVALUATION TOOLS
as a V
OUT
over-voltage clamp.
• PGA308EVM (Hardware and Software)
For detailed application information, see the PGA308
– Calibration and Configuration
User's Guide (SBOU069) available for download at
– Sensor Emulation
www.ti.com.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2008–2010, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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