MIC284_05 Datasheet, PDF (6/20 Pages) Micrel Semiconductor – Two-Zone Thermal Supervisor

MIC284
Functional Diagram
T1
2:1
MUX
VDD
Bandgap
Sensor
and
Reference
1-Bit
DAC
TEMPERATURE-TO-DIGITAL
CONVERTER
Digital Filter
and
Control
Logic
Micrel, Inc
A0
DATA
CLK
2-Wire
Serial Bus
Interface
Pointer
Register
MIC284
Result
Registers
T_SET & /CRIT
Setpoint
Registers
Temperature
Hysteresis
Registers
Configuration
Register
GND
State
Machine
and
Digital
Comparator
Open-Drain
Output
/INT
/CRIT
Functional Description
Pin Descriptions
Part Number
Inputs
A0
MIC 284 S lave Addres s
B inary
Hex
VDD: Power supply input. See electrical specifications.
GND: Ground return for all MIC284 functions.
CLK: Clock input to the MIC284 from the two-wire serial bus.
The clock signal is provided by the host, and is shared by all
devices on the bus.
DATA: Serial data I/O pin that connects to the two-wire serial
bus. DATA is bi-directional and has an open-drain output driver.
An external pull-up resistor or current source somewhere in
the system is necessary on this line. This line is shared by
all devices on the bus.
A0: This inputs sets the least significant bit of the MIC284’s
7-bit slave address. The six most-significant bits are fixed and
are determined by the part number ordered. (See ordering
information table above.) Each MIC284 will only respond to
its own unique slave address, allowing up to eight MIC284s to
share a single bus. A match between the MIC284’s address
and the address specified in the serial bit stream must be
made to initiate communication. A0 should be tied directly
to VDD or ground. See "Temperature Measurement and
Power On" for more information. A0 determines the slave
address as shown in Table 1:
MIC 284-0
0
100 1000_b
48_h
1
100 1001_b
49_h
MIC 284-1
0
100 1010_b
4A_h
1
100 1011_b
4B _h
MIC 284-2
0
100 1100_b
4C _h
1
100 1101_b
4D_h
MIC 284-3
0
100 1110_b
4E _h
1
100 1111_b
4F _h
Table 1. MIC284 Slave Address Settings
/INT: Temperature events are indicated to external circuitry
via this output. Operation of the /INT output is controlled by
the MODE and IM bits in the MIC284’s configuration register.
See "Comparator and Interrupt Modes" below. This output
is open-drain and may be wire-OR’ed with other open-drain
signals. Most systems will require a pull-up resistor or current
source on this pin. If the IM bit in the configuration register
is set, it prevents the /INT output from sinking current. In
I²C and SMBus systems, the IM bit is therefore an interrupt
MIC284
6
September 2005