Datasheet
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
EXC
GND
A
V
SA
V
IN1
V
IN2
V
FB
V
OUT
V
SJ
TEST
V
SD
GND
D
PRG
SCL
SDA
TEMP
IN
REF /REF
IN OUT
PGA309
SBOS292C –DECEMBER 2003–REVISED JANUARY 2011
www.ti.com
PIN CONFIGURATION
PW PACKAGE
TSSOP-16
(TOP VIEW)
PIN DESCRIPTIONS
PIN NO. NAME DESCRIPTION
Bridge sensor excitation. Connect to bridge if linearization and/or internal reference for bridge excitation
1 V
EXC
is to be used.
2 GND
A
Analog ground. Connect to analog ground return path for V
SA
. Should be same as GND
D
.
3 V
SA
Analog voltage supply. Connect to analog voltage supply. To be within 200mV of V
SD
.
Signal input voltage 1. Connect to + or – output of sensor bridge. Internal multiplexer can change
4 V
IN1
connection internally to Front-End PGA.
Signal input voltage 2. Connect to + or – output of sensor bridge. Internal multiplexer can change
5 V
IN2
connection internally to Front-End PGA.
V
OUT
feedback pin. Voltage feedback sense point for over/under-scale limit circuitry. When internal gain
set resistors for the output amplifier are used, this is also the voltage feedback sense point for the
6 V
FB
output amplifier. V
FB
in combination with V
SJ
allows for ease of external filter and protection circuits
without degrading the PGA309 V
OUT
accuracy. V
FB
must always be connected to either V
OUT
or the
point of feedback for V
OUT
, if external protection is used.
7 V
OUT
Analog output voltage of conditioned sensor.
Output amplifier summing junction. Use for output amplifier compensation when driving large capacitive
8 V
SJ
loads (> 100pF) and/or for using external gain setting resistors for the output amplifier.
9 TEST Test/External controller mode pin. Pull to GND
D
in normal mode.
10 V
SD
Digital voltage supply. Connect to digital voltage supply. To be within 200mV of V
SA
.
11 GND
D
Digital ground. Connect to digital ground return path for V
SD
. Should be same as GND
A
.
Single-wire interface program pin. UART-type interface for digital calibration of the PGA309 over a
12 PRG single wire. Can be connected to V
OUT
for a three-lead (V
S
, GND, V
OUT
) digitally-programmable sensor
assembly.
Clock input/output for Two-Wire, industry-standard compatible interface for reading and writing digital
13 SCL calibration and configuration from external EEPROM. Can also communicate directly to the registers in
the PGA309 through the Two-Wire, industry-standard compatible interface.
Data input/output for Two-Wire, industry-standard compatible interface for reading and writing digital
14 SDA calibration and configuration from external 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, or an external temperature sensing device such as diode
junction, RTD, or thermistor. This input can be internally gained by 1, 2, 4, or 8. In addition, this input
15 TEMP
IN
can be read differentially with respect to V
GNDA
, V
EXC
, or the internal/external V
REF
. There is also an
internal, register-selectable, 7mA current source (I
TEMP
) that can be connected to TEMP
IN
as an RTD,
thermistor, or diode excitation source.
Reference input/output pin. As an output, the internal reference (selectable as 2.5V or 4.096V) is
16 REF
IN
/REF
OUT
available for system use on this pin. As an input, the internal reference may be disabled and an
external reference can then be applied as the reference for the PGA309.
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Product Folder Link(s): PGA309