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Preliminary
Figure 1: PGA309DK Typical System Setup
3.0 PGA309 Sensor Interface Board Overview
(Refer to PGA309 Sensor Interface Board Schematic)
3.1 Input/Output
Bridge sensor input connections are made though Tin, an 8-position screw terminal strip. In parallel with Tin
are plated-through holes that are provided for solder connections if so desired. The connections from the
PGA309 Sensor Interface Board to the PGA309 PC Interface Board are provided through Tio, an 8-position
screw terminal strip. This connector provides ease of connections to wires for the required selected signals
when placing the PGA309 Sensor Interface Board inside a temperature chamber for PGA309 + Sensor
calibration. In parallel with Tio is Jtest which provides a means for direct plug-in connection to the PGA309 PC
Interface Board. This is useful for initial checkout of the PGA309DK system.
3.2 Jumper Configuration
J1, J2, J3, J4, J5, J10 and J11 allow flexibility in the configuration of the connection to a bridge sensor. These
jumpers also allow connection of the on-board test resistor RTEST used for testing functionality of the PGA309
without any bridge sensor connected. Rt+ and Rt- allow for resistors to be used in the top or bottom of the
bridge sensor’s excitation path for one method of measuring bridge temperature by total bridge resistance
changes. Jumper J6 is used to configure the PGA309 circuit for external or internal temperature sensing. If
external temperature sensing using an RTD or external diode is to be used then set J6 to EXT and remove the
J1 jumper entirely to avoid any interaction with Rt+ or Rt-. J9 provides hardware configuration for either
internal or external reference voltage. J8 is used when Vout is to be tied to PRG for a 3-terminal sensor
module configuration. J12 and J7 together decide if the Test pin on the PGA309 is to be controlled by the
PGA309 PC Interface Board or hardware-programmed on the PGA309 Sensor Interface Board.
3.3 PGA309 + External SOT23-5 EEPROM
U1 is the PGA309 for evaluation. Also on-board is a 16k-bit, external, SOT23-5, industry standard Two-Wire,
EEPROM, U2. Although the PGA309 needs only 1k-bit of external EEPROM to access its configuration
registers plus the maximum number of 17 temperature coefficients, both the One-Wire and Two-Wire
interfaces allow access to locations in much larger EEPROMs which can be used to store user-specific
information such as a serial number, lot and date code information, etc.
Rev 1.5
2/26/2004 8:46:00 AM
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