EMC1412-1-AC3-TR SMSC, EMC1412-1-AC3-TR Datasheet - Page 14

• Manufacturer Part Number: EMC1412-1-AC3-TR
• Description: Board Mount Temperature Sensors Temp Sensor w/ Beta Comp & Select
• Manufacturer: SMSC

Specifications of EMC1412-1-AC3-TR

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Revision 1.38 (10-25-10)
5.1.3
5.1.4
5.1.5
Shared THERM
The EMC1412-1 SMBus address is hard coded to 1001_100(r/w).
The EMC1412-2 SMBus address is hard coded to 1001_101(r/w).
THERM Pin Considerations
Because of the decode method used to determine the SMBus Address, it is important that the pull-up
resistance on the THERM pin be within the tolerances shown in
resistor on the THERM pin must be connected to the same 3.3V supply that drives the VDD pin.
For 15ms after power up, the THERM pin must not be pulled low or the SMBus address will not be
decoded properly. If the system requirements do not permit these conditions, the THERM pin must be
isolated from its hard-wired OR’d bus during this time.
One method of isolating this pin is shown in
SMBus Data Bytes
All SMBus Data bytes are sent most significant bit first and composed of 8-bits of information.
SMBus ACK and NACK Bits
The SMBus client will acknowledge all data bytes that it receives. This is done by the client device
pulling the SMBus Data line low after the 8th bit of each byte that is transmitted. This applies to both
the Write Byte and Block Write protocols.
The Host will NACK (not acknowledge) the last data byte to be received from the client by holding the
SMBus data line high after the 8th data bit has been sent. For the Block Read protocol, the Host will
ACK each data byte that it receives except the last data byte.
22K
+2.5 - 5V
PULL UP RESISTOR ON
Table 5.1 SMBus Address Decode (continued)
THERM PIN (±5%)
4.7K – 33k
Figure 5.2 Isolating THERM Pin
22k
33k
DATASHEET
THERM / ADDR
Multiple Channel 1°C Temperature Sensor with Beta Compensation
14
Figure
VDD
SMBUS ADDRESS
DN
DP
0011_100(r/w)b
0111_100(r/w)b
5.2.
+3.3V
1
2
3
4
EMC1412
Table
5.1. Additionally, the pull-up
8
7
6
5
ALERT
SMCLK
SMDATA
GND
SMSC EMC1412
Datasheet