ADT7470ARQZ-REEL Analog Devices Inc, ADT7470ARQZ-REEL Datasheet - Page 15

• Manufacturer Part Number: ADT7470ARQZ-REEL
• Description: IC,Motor Controller,SSOP,16PIN
• Manufacturer: Analog Devices Inc

Specifications of ADT7470ARQZ-REEL

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Fan Speed Control, Register Bank
• Sensor Type: External
• Sensing Temperature: External Sensor
• Output Type: I²C™
• Output Alarm: No
• 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
• For Use With: EVAL-ADT7470EBZ - BOARD EVALUATION FOR ADT7470
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TEMPERATURE MEASUREMENT LIMITS
High and low temperature limits can be individually set for
each of the TPM05/06s that the ADT7470 is monitoring. The
temperature limit registers are at address 0x44 to 0x57. The
power-on default value for all TMP05/06 lower limits is −127°C
(0x81). The power –on default value for all TMP05/06 upper
limits is +127°C (0x7F). See Table 9 for details on the
temperature limit registers.
If the temperature measured from a TMP05/06 exceeds the
upper or lower limit, then a status bit in the Interrupt Status
registers will be set to 1. See Table 12 and Table 13 for more
details on the temperature status bits.
SMBALERT will assert is any temperature exceeds either the
upper or lower limits. The temperature measurements can be
masked as interrupt sources for SMBALERT using the interrupt
mask registers, 0x72 and 0x73. See
more details on the interrupt mask registers.
Table 14
and
Table 15
for
Rev. C | Page 15 of 40
THERMAL ZONES FOR AUTOMATIC FAN CONTROL
The ADT7470 can control up to four independent thermal zones
with individual fans. The user can configure which TMP05
controls which fan via register 0x7C and 0x7D.For each of the four
thermal zones, an individual TMP05, or the hottest TMP05 in the
daisy chain, can control the fan. In a system with n TMP05s, it is
possible to have 1 or n TMP05s controlling each fan.
Thermal Zone T
For each of the four thermal zones, the user can configure the
minimum temperature at which the fans run. Registers 0x6E to
0x71 should be configured with the minimum temperature for
each thermal zone. When the temperature exceeds T
thermal zone, the fans run at minimum speed (PWM
fan speed increases to maximum speed (PWM
20°C]. Fan on/off hysteresis is set at 4°C so that the fans turn off
4°C below the temperature at which they turn on. This prevents
fan chatter in the system.
MIN
MAX
) at [T
ADT7470
MIN
MIN
for that
MIN
). The
+