The PGA309 is a programmable analog signal conditioner designed for bridge sensors

PGA309

Manufacturer Part NumberPGA309
DescriptionThe PGA309 is a programmable analog signal conditioner designed for bridge sensors
ManufacturerTexas Instruments
PGA309 datasheet
 


Specifications of PGA309

Vs(min)(v)2.7Vs(max)(v)5
Operating Temperature Range(c)-40 to 125Pin/package16TSSOP
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FEATURES
1
Complete Bridge Sensor Conditioner
2
Voltage Output: Ratiometric or Absolute
Digital Cal: No Potentiometers/Sensor Trims
Sensor Error Compensation
– Span, Offset, and Temperature Drifts
Low Error, Time-Stable
Sensor Linearization Circuitry
Temperature Sense: Internal or External
Calibration Lookup Table Logic
– Uses External EEPROM (SOT23-5)
Over/Under-Scale Limiting
Sensor Fault Detection
+2.7V TO +5.5V Operation
–40°C to +125°C Operation
Small TSSOP-16 Package
APPLICATIONS
Bridge Sensors
Remote 4-20mA Transmitters
Strain, Load, and Weigh Scales
Automotive Sensors
EVALUATION TOOLS
Hardware Designer’s Kit (PGA309EVM)
– Temperature Eval of PGA309 + Sensor
– Full Programming of PGA309
– Sensor Compensation Analysis Tool
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.
All trademarks are the property of their respective owners.
2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Voltage Output
Programmable Sensor Conditioner
Check for Samples:
PGA309
DESCRIPTION
The PGA309 is a programmable analog signal
conditioner designed for bridge sensors. The analog
signal path amplifies the sensor signal and provides
digital calibration for zero, span, zero drift, span drift,
and sensor linearization errors with applied stress
(pressure, strain, etc.). The calibration is done via a
One-Wire digital serial interface or through a
Two-Wire
calibration
nonvolatile memory (typically SOT23-5) to eliminate
manual trimming and achieve long-term stability.
The all-analog signal path contains a 2x2 input
multiplexer
instrumentation amplifier, linearization circuit, voltage
reference, internal oscillator, control logic, and an
output
compensates for sensor dc offsets.
The core of the PGA309 is the precision, low-drift, no
1/f noise Front-End PGA (Programmable Gain
Amplifier). The overall gain of the Front-End PGA +
Output Amplifier can be adjusted from 2.7V/V to
1152V/V. The polarity of the inputs can be switched
through the input mux to accommodate sensors with
unknown polarity output. The Fault Monitor circuit
detects and signals sensor burnout, overload, and
system fault conditions.
For detailed application information, see the
User's Guide (SBOU024)
www.ti.com.
P
psi
0
50
+125 C
°
T
-
40 C
°
SBOS292C – DECEMBER 2003 – REVISED JANUARY 2011
industry-standard
connection.
parameters
are
stored
in
(mux),
auto-zero
programmable-gain
amplifier.
Programmable
level
available for download at
V
S
Ref
Nonlinear
Linearization
V
EXC
Circuit
PGA309
Bridge
Transducer
Lin DAC
Analog Sensor Linearization
Fault
Over/Under
Auto- Zero
Monitor
Scale Limiter
PGA
Analog Signal Conditioning
Digital
Int Temp
Temperature
Compensation
Temp
Control Register
Ext Temp
ADC
Interface Circuitry
Ext Temp
Copyright © 2003–2011, Texas Instruments Incorporated
PGA309
The
external
shifting
PGA309
Linear
V
OUT
Digital Cal
EEPROM
(SOT23-5)

PGA309 Summary of contents

  • Page 1

    ... The core of the PGA309 is the precision, low-drift, no 1/f noise Front-End PGA (Programmable Gain Amplifier). The overall gain of the Front-End PGA + Output Amplifier can be adjusted from 2.7V/V to 1152V/V. The polarity of the inputs can be switched through the input mux to accommodate sensors with unknown polarity output ...

  • Page 2

    ... Input terminals are diode-clamped to the power-supply rails. Input signals that can swing more than 0.5V beyond the supply rails should be current limited to 10mA or less. 2 Submit Documentation Feedback PACKAGE DESIGNATOR PW (1) Copyright © 2003–2011, Texas Instruments Incorporated Product Folder Link(s): PGA309 www.ti.com (1) PACKAGE MARKING PGA309 PGA309 UNIT +7.0 V –0 +0 ±150 mA ± –60 to +150 °C – ...

  • Page 3

    ... Gain Error Gain Error Drift Offset Offset Drift (1) PGA309 total differential gain from input (V gain) × (Gain DAC). (2) RTI = Referred-to-input. RTO = referred to output. (3) Linear input range is the allowed min/max voltage on the V The allowed common-mode and differential voltage depends on gain and offset settings. Refer to the information. Copyright © ...

  • Page 4

    ... REF Ratio Register 5—bits D2, D1 ‘001’ REF Ratio Register 5—bits D2, D1 ‘000’ REF Product Folder Link(s): PGA309 www.ti.com must equal V ), GND = GND = 0, and PGA309 MIN TYP MAX 0. 0 – 1.5 S 100 0.25 ± ...

  • Page 5

    ... V SA INX might be higher or lower than the input CMR of the PGA input EXC Product Folder Link(s): PGA309 PGA309 must equal V ), GND = GND = 0, and PGA309 MIN TYP MAX V − 1 − 0.1 SA EXC 40 100 V − 0. − 0.12 ...

  • Page 6

    ... PGA At dc and PGA At dc and PGA Register 6, bit D11 = 1 Product Folder Link(s): PGA309 www.ti.com must equal V ), GND = GND = 0, and PGA309 MIN TYP MAX 800 400 200 150 0.05 0. ppm/°C < 105 100 ±V /G ...

  • Page 7

    ... Register 3, bit D11 = 1 With respect ±127 steps, 7-bit + sign With respect to V REF I = 5mA EXC Short-circuit V output current EXC Bus speed Serial speed baud rate PGA309 to EEPROM (SCL frequency) Low High Hysteresis Open drain 5mA SINK +5V, without bridge load rising ...

  • Page 8

    ... EEPROM. Can also communicate directly to the registers in the PGA309 through the Two-Wire, industry-standard compatible interface. External temperature signal input. PGA309 can be configured to read a bridge current sense resistor as an indicator of bridge temperature external temperature sensing device such as diode junction, RTD, or thermistor ...

  • Page 9

    ... G OUTAMP 100k 1M 10 Product Folder Link(s): PGA309 PGA309 must equal V ), GND = GND = 0, and CURRENT vs TEMPERATURE B Average 105 125 145 Temperature ( C) ° Figure 2. RTO of Front- End PGA ...

  • Page 10

    ... TO 10Hz PEAK-TO-PEAK NOISE +61mV V = 4.096V IN REF CLK_CFG = 00 (default) Measured After Bandpass Filter 0.1Hz Second-Order High-Pass 10Hz Fourth-Order Low-Pass Product Folder Link(s): PGA309 www.ti.com must equal V ), GND = GND = 0, and TEMPERATURE Q All Blocks Enabled ...

  • Page 11

    ... SUPPLY ANALOG SD SUPPLY DIGITAL SA 1 Coarse Offset Adjust = 0mV CLK_CFG = 00 (default) 0.1 0. 10k 50k Gain = 8 Gain = 8 Product Folder Link(s): PGA309 PGA309 must equal V ), GND = GND = 0, and INPUT VOLTAGE NOISE DENSITY 10 100 1k 10k 100k Frequency (Hz) Figure 14. LARGE-SIGNAL STEP RESPONSE Gain = 1152 ...

  • Page 12

    ... GAIN DAC TYPICAL ERROR vs CODE 10000 20000 30000 40000 50000 60000 Code (LSB) Figure 23. Product Folder Link(s): PGA309 www.ti.com must equal V ), GND = GND = 0, and OVERVOLTAGE RECOVERY V OUT V IN Time (100 s/div) m Figure 20. ZERO DAC TYPICAL ERROR vs CODE ...

  • Page 13

    ... Combined coarse and fine offset adjust. 3. Lower impedance possible by using a dropping resistor in series with the bridge. GAIN SCALING The core of the PGA309 is the precision low-drift and no 1/f noise Front-End PGA. The overall gain of the Front-End PGA + Output Amplifier can be adjusted from 2.7V/V to 1152V/V. The polarity of the inputs can be switched through the 2x2 input mux to accommodate sensors with unknown polarity output ...

  • Page 14

    ... Offset Adjust IN1 Front-End PGA (Gain 4 to 128) V IN2 Bridge Sensor R Fault Conditions TEMP Monitoring Circuit TEST Test Logic Figure 24. Simplified Diagram of the PGA309 in a Typical Configuration 14 Submit Documentation Feedback + Power-On REF K Reset REF V FB Linearization DAC ...

  • Page 15

    ... Over-Scale Limit level or well below the set Under-Scale Limit level. The state of the fault condition can be read in digital form in Register 8—Alarm Status Register. If the Over/Under-Scale Limit is disabled, the PGA309 output voltage will still pin back through be driven within 100mV of either V depending upon the alarm configuration setting. ...

  • Page 16

    ... PGA309, and reset the internal registers and circuitry to an initial state. This reset also occurs when the supply is detected to be invalid, so that the PGA309 known state when the supply becomes valid again. The rising threshold for this circuit is typically 2.2V and the falling threshold is typically 1 ...

  • Page 17

    ... Front-End PGA Zero Auto INN Zero INT/EXT FB Select Alarm Register Inputs Fault Monitor Circuit Output Gain Select ( Range Figure 25. Detailed Block Diagram Product Folder Link(s): PGA309 PGA309 POR Internal Set REF Bandgap Reference R ...

  • Page 18

    ... Updated document format to current standards ................................................................................................................... • Deleted lead temperature specification from • Added PGA Transfer Function section ............................................................................................................................... 18 Submit Documentation Feedback REVISION HISTORY Absolute Maximum Ratings table .................................................................. Copyright © 2003–2011, Texas Instruments Incorporated Product Folder Link(s): PGA309 www.ti.com Page ...

  • Page 19

    ... TSSOP PGA309AIPWRG4 ACTIVE TSSOP PGA309AIPWT ACTIVE TSSOP PGA309AIPWTG4 ACTIVE TSSOP (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. ...

  • Page 20

    ... TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Type Drawing PGA309AIPWR TSSOP PW PGA309AIPWT TSSOP PW PACKAGE MATERIALS INFORMATION Pins SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 16 2500 330.0 12.4 6.9 16 250 180.0 12.4 6.9 Pack Materials-Page 1 12-Dec-2011 Pin1 (mm) ...

  • Page 21

    ... Device Package Type PGA309AIPWR TSSOP PGA309AIPWT TSSOP PACKAGE MATERIALS INFORMATION Package Drawing Pins SPQ Length (mm 2500 PW 16 250 Pack Materials-Page 2 12-Dec-2011 Width (mm) Height (mm) 346.0 346.0 29.0 210.0 185.0 35.0 ...

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  • Page 24

    ... Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’ ...