TMP421 Datasheet, PDF (17/30 Pages) Burr-Brown (TI) – ±1°C Remote and Local TEMPERATURE SENSOR in SOT23-8

www.ti.com
SERIAL BUS ADDRESS
To communicate with the TMP421/22/23, the master
must first address slave devices via a slave address
byte. The slave address byte consists of seven
address bits, and a direction bit indicating the intent
of executing a read or write operation.
Two-Wire Interface Slave Device Addresses
The TMP421 supports nine slave device addresses
and the TMP422 supports four slave device
addresses. The TMP423 has one of two
factory-preset slave addresses.
The slave device address for the TMP421 is set by
the A1 and A0 pins according to Table 9.
The slave device address for the TMP422 is set by
the connections between the external transistors and
the TMP422 according to Figure 15 and Table 10. If
one of the channels is unused, the respective DXP
connection should be connected to GND, and the
TMP421
TMP422
TMP423
SBOS398B – JULY 2007 – REVISED MARCH 2008
DXN connection should be left unconnected. The
polarity of the transistor for external channel 2 (pins 3
and 4) sets the least significant bit of the slave
address. The polarity of the transistor for external
channel 1 (pins 1 and 2) sets the next least
significant bit of the slave address.
Table 9. TMP421 Slave Address Options
TWO-WIRE SLAVE
ADDRESS
0011 100
0011 101
0011 110
0011 111
0101 010
1001 100
1001 101
1001 110
1001 111
A1
Float
Float
0
1
Float
0
0
1
1
A0
0
1
Float
Float
Float
0
1
0
1
TWO-WIRE SLAVE ADDRESS
1001 100
1001 101
1001 110
1001 111
Table 10. TMP422 Slave Address Options
DX1
DXP1
DXP1
DXN1
DXN1
DX2
DXN1
DXN1
DXP1
DXP1
DX3
DXP2
DXN2
DXP2
DXN2
DX4
DXN2
DXP2
DXN2
DXP2
SCL
SDA
V+
DX1 V+
Q0
DX2 SCL
DX3 SDA
Q1
DX4 GND
Address = 1001100
Q2
Q3
DX1 V+
DX2 SCL
DX3 SDA
DX4 GND
Address = 1001101
DX1 V+
Q4
DX2 SCL
DX3 SDA
Q5
DX4 GND
Address = 1001110
Q6
Q7
DX1 V+
DX2 SCL
DX3 SDA
DX4 GND
Address = 1001111
Figure 15. TMP422 Connections for Device Address Setup
Copyright © 2007–2008, Texas Instruments Incorporated
Submit Documentation Feedback
17
Product Folder Link(s): TMP421 TMP422 TMP423