ADM1033ARQZ-REEL7 ON Semiconductor, ADM1033ARQZ-REEL7 Datasheet - Page 14

• Manufacturer Part Number: ADM1033ARQZ-REEL7
• Description: IC THERM/FAN SPEED CTRLR 16-QSOP
• Manufacturer: ON Semiconductor

Specifications of ADM1033ARQZ-REEL7

• 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 ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

capacitor value up to 1000 pF may be placed between the D+
and D− inputs to filter the noise. However, additional
parasitic capacitance on the lines between D+, D−, and the
thermal diode should also be considered. The total
capacitance should never be greater than 1000 pF.
operating currents of I, (N1 x I), and (N2 x I). The resulting
waveform is passed through a 65 kHz low−pass filter to
remove noise, then to a chopper−stabilized amplifier that
amplifies and rectifies the waveform. This produces a dc
voltage proportional to DV
determine the temperature of the thermal diode, while
automatically compensating for any series resistance on the
D+ and/or D− lines. The temperature is stored in two
registers as a 13−bit word.
performed by averaging the results of 16 measurement cycles
at conversion rates of less than or equal to 8 Hz. An external
temperature measurement takes nominally 32 ms when
averaging is enabled and 6 ms when averaging is disabled.
ADM1033 can theoretically measure temperatures from
−64°C to +191.96875°C, although these are outside its
operating range. The extended temperature resolution data
format is shown in Table 5. The data for the local and remote
Additional Functions
available on the ADM1033 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).
If the sensor is used in a very noisy environment, a
To measure each DV
To further reduce the effects of noise, digital filtering is
One LSB of the ADC corresponds to 0.03125°C. The
Several other temperature measurement functions
The ADM1033 performs averaging at conversion rates of
TRANSISTOR
SENSING
REMOTE
BE
, the sensor is switched between
BE
D+
D–
. These voltage measurements
I
Figure 27. ADM1033 Signal Conditioning
N2 × I
N1 × I
http://onsemi.com
I
BIAS
LOW−PASS FILTER
14
f
C
channels is stored in the extended temperature resolution
registers (Reg. 0x40 = Local, Reg. 0x42 = Remote 1).
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.
Single−Channel ADC Conversions
temperature channels: the local temperature channel, and
the remote channel. However, the user has the option to set
up the ADM1033 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 ADM1033 converts
on all 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
Table 7. Temperature Measurement Limit Registers
= 65kHz
High and low temperature limit registers are associated
In normal operating mode, the ADM1033 converts on two
Register
Register
0x0B
0x0C
0x0D
0x0E
0x40
0x41
0x42
0x43
0x0F
0x10
V
DD
Local High Limit
Local Low Limit
Local THERM Limit
Remote 1 High Limit
Remote 1 Low Limit
Remote 1 THERM Limit
Local Temperature, LSBs
Local Temperature, MSBs
Remote 1 Temperature, LSBs
Remote 1 Temperature, MSBs
Description
Description
V
TO ADC
V
OUT+
OUT–
0x8B (75°C)
0x8B (75°C)
0x54 (20°C)
0x95 (85°C)
0x54 (20°C)
0x95 (85°C)
Default
Default
0x00
0x00
0x00
0x00