ADM1022ARQ-REEL ON Semiconductor, ADM1022ARQ-REEL Datasheet - Page 7

• Manufacturer Part Number: ADM1022ARQ-REEL
• Description: IC SENSOR TEMP/DET 3/5.5V 16QSOP
• Manufacturer: ON Semiconductor
• Type: Temperature Sensorr

Specifications of ADM1022ARQ-REEL

• Rohs Status: RoHS non-compliant
• Input Type: Logic
• Output Type: Analog
• Interface: Serial
• Current - Supply: 2.6mA
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP

400
350
300
250
200
150
100
2.3
2.2
2.1
2.0
1.9
1.8
1.7
–40
10
–40
9
8
7
6
5
4
3
2
1
0
50
–30
–30
–20
–20
500
V
DD
–10
–10
RST1
RST2
= 3.0V
0
0
5k
10
10
20
TEMPERATURE – C
20
TEMPERATURE – C
50k
FREQUENCY – Hz
30
30
V
10mV SQ. WAVE
DD
40
40
V
100k
= 3.3V
DD
50
50
= 5.5V
60
60
500k
70
70
80
80
5M
90
90
100
100
110
110
25M
120
120
50M
130
130
GENERAL DESCRIPTION
The ADM1022 is a low-cost temperature monitor and fan con-
troller for microprocessor-based systems. The temperature of
one or two remote sensor diodes may be measured, allowing
monitoring of processor temperature in single- or dual-processor
systems. The chip also contains an on-chip sensor to allow
ambient temperature to be monitored.
Measured values can be read out via a serial System Manage-
ment Bus, and values for limit comparisons can be programmed
in over the same serial bus.
The ADM1022 also contains a DAC for fan speed control.
Automatic hardware temperature trip points are provided for
fault tolerant fan control and the fan will be driven to full speed
if they are exceeded. Two interrupt outputs are provided, which
will be asserted if the software or hardware limits are exceeded.
Finally, the chip has two supply voltage monitors for brownout
detection. These drive two reset pins, one of which is bidirec-
tional. A manual reset input is also provided.
INTERNAL REGISTERS OF THE ADM1022
A brief description of the ADM1022’s principal internal regis-
ters is given below. More detailed information on the function
of each register is given in Tables IV to IX.
Configuration Register: Provides control and configuration.
Address Pointer Register: This register contains the address that
selects one of the other internal registers. When writing to the
ADM1022, the first byte of data is always a register address, which
is written to the Address Pointer Register.
Interrupt (INT) Status Register: This register provides status
of each Interrupt event. It is also mirrored by a second register
at address 4Ch.
Interrupt (INT) Mask Register: Allows masking of individual
interrupt sources.
Value and Limit Registers: The results of temperature measure-
ments are stored in these registers, along with their limit values.
Analog Output Register: The code controlling the analog out-
put DAC is stored in this register.
SERIAL BUS INTERFACE
Control of the ADM1022 is carried out via the serial bus. The
ADM1022 is connected to this bus as a slave device, under the
control of a master device, e.g., the PIIX4.
The ADM1022 has a 7-bit serial bus address. When the device is
powered up, it will do so with a default serial bus address. The five
MSBs of the address are set to 01011, the two LSBs are deter-
mined by the logical states of Pin 13 (ADD/NTEST_OUT).
This is a three-state input that can be grounded, connected to V
or left open-circuit to give three different addresses. The state of
the ADD pin is only sampled at power-up, so changing ADD
with power-on will have no effect until the device is powered
off then on again.
ADD Pin
GND
No Connect
V
CC
Table I. ADD Pin Truth Table
A1
1
0
0
ADM1022
A0
0
0
1
CC