ADM1034ARQZ-R7 ON Semiconductor, ADM1034ARQZ-R7 Datasheet - Page 15

• Manufacturer Part Number: ADM1034ARQZ-R7
• Description: IC THERM/FAN SPEED CTLR 16-QSOP
• Manufacturer: ON Semiconductor

Specifications of ADM1034ARQZ-R7

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

with each temperature measurement channel. Exceeding the
programmed high and low limits sets the appropriate status
bit. Exceeding either limit can cause an SMBusALERT
interrupt.
Additional Functions
available on the ADM1034 offer the systems designer added
flexibility.
Turn−off Averaging
less than or equal to 8 conversions per second. This means
that the value in the measurement register is the average of 16
measurements. For faster measurements, set the conversion
rate to 16 conversions per second or greater. (Averaging is not
carried out at these conversion rates.) Alternatively, switch
off averaging at the slower conversion rates by setting Bit 1
(AVG) of Configuration 1 Register (Address 0x01).
Single−Channel ADC Conversions
three temperature channels: the local temperature channel,
and the remote 1 and remote 2 channels. However, the user
has the option to set up the ADM1034 to convert on one
channel only. To enable single−channel mode, the user sets
the round−robin bit (Bit 7) in Configuration Register 2
(Address 0x02) to 0. When the round−robin bit equals 1, the
ADM1034 converts on all three temperature channels. In
single−channel mode, it converts on one channel only, to be
determined by the state of the channel selector bits (Bits 5
and 4) of the Configuration Register 2 (Address 0x02).
Table 6. Temperature Measurement Registers
High and low temperature limit registers are associated
Several other temperature measurement functions
The ADM1034 performs averaging at conversion rates of
In normal operating mode, the ADM1034 converts on
Register
0x40
0x41
0x42
0x43
0x44
0x45
TRANSISTOR
SENSING
REMOTE
Local Temperature, LSBs
Local Temperature, MSBs
Remote 1 Temperature, LSBs
Remote 1 Temperature, MSBs
Remote 2 Temperature, LSBs
Remote 2 Temperature, MSBs
Description
D+
D–
I
Figure 27. ADM1034 Signal Conditioning
N2 × I
N1 × I
Default
0x00
0x00
0x00
0x00
0x00
0x00
http://onsemi.com
I
BIAS
LOW−PASS FILTER
15
f
C
Removing Temperature Errors
avoid high frequency clocks when routing the D+ and D−
traces around a system board. Even when the recommended
layout guidelines are followed, temperature errors attributed
to noise coupled onto the D+ and D− lines remain. High
frequency noise generally gives temperature measurements
that are consistently too high. The ADM1034 has Local,
Remote 1, and Remote 2 temperature offset registers at
0x16, 0x17, and 0x18; one for each channel. By completing
a one−time calibration, the user can determine the offset
caused by the system board noise and remove it using the
offset registers. The registers automatically add a twos
compliment word to the remote temperature measurements,
ensuring correct readings in the value registers.
Table 7. Temperature Measurement Limit Registers
= 65kHz
Table 8. Channel Selector
As CPUs run faster and faster, it gets more difficult to
Register
Bits 5:4
0x0B
0x0C
0x0D
0x0E
0x0F
0x10
0x11
0x12
0x13
00
01
10
11
V
DD
Local Channel = Default
Remote 1 Channel
Remote 2 Channel
Reserved
Local High Limit
Local Low Limit
Local THERM Limit
Remote 1 High Limit
Remote 1 Low Limit
Remote 1 THERM Limit
Remote 2 High Limit
Remote 2 Low Limit
Remote 2 THERM Limit
Channel Selector (Configuration 2)
Description
V
TO ADC
V
OUT+
OUT–
0x8B (75°C)
0x8B (75°C)
0x8B (75°C)
0x54 (20°C)
0x95 (85°C)
0x54 (20°C)
0x95 (85°C)
0x54 (20°C)
0x95 (85°C)
Default