ADM1022ARQ-REEL ON Semiconductor, ADM1022ARQ-REEL Datasheet - Page 13

• 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

THERM INPUT/OUTPUT
Pin 11 may be configured as an input for a second temperature
sensor by setting Bit 7 of the Configuration Register, or it may
be used as an interrupt output by clearing Bit 7 of the Configu-
ration Register, which is its default condition. The Thermal
Management Input/Output (THERM) is a logic input/open-
drain output. It can also function as a logic input. If THERM is
taken low by an external source, the analog output will be forced
to FFh to switch a controlled fan to maximum speed and
FAN_OFF will be negated.
THERM OPERATING MODE
THERM responds only to the “hardware” temperature limits
at addresses 13h, 14h, 17h and 18h, not to the software pro-
grammed limits. The function of these registers was described
earlier with regard to fault tolerant fan speed control.
THERM will go low if the hardware temperature limit is exceeded
for three consecutive measurements. It will remain low until the
HARDWARE
TRIP POINT
REGISTERS
AND LIMIT
ANALOG
OUTPUT
THERM
VALUE
FROM
VALUE
TEMP
LIMIT
LIMIT
HIGH
LOW
PROGRAMMED
VALUE
COMPARA-
TORS
HIGH
LIMIT
LOW
AND
1 = OUT
LIMIT
OF
FF
H
GPI
THERM
DEMULTI-
PLEXER
DATA
5
DIODE 2 FAULT
DIODE 1 FAULT
FF
EXT. TEMP2
EXT. TEMP1
RESERVED
FROM BUS
INT. TEMP
H
MASKING
8 MASK BITS
THERM
REGISTER)
ORDER AS
DATA
(SAME BIT
EXT
THERM
INPUT
GPI
STATUS
0
1
2
3
4
5
6
7
INTERRUPT
REGISTER
INTERRUPT
REGISTER
STATUS
MASK
THIS CONNECTION ONLY RELEVANT IF
THERM IS PULLED LOW EXTERNALLY.
temperature falls five degrees below the limit for three con-
secutive measurements. While THERM is low, the analog
output will go to FFh to boost a controlled fan to full speed
and FAN_OFF will be negated.
When the Fault Tolerant Fan Control state is exited, the analog
FAN_SPD output returns to its previously programmed value,
which may have been changed during the time that the FAN_SPD
output was forced to FFh.
INTERRUPT STRUCTURE
The Interrupt Structure of the ADM1022 is shown in more
detail in Figure 17. As each measurement value is obtained and
stored in the appropriate value register, the value and the limits
from the corresponding limit registers are fed to the high and
low limit comparators. The result of each comparison (1 = out
of limit, 0 = in limit) is routed to the corresponding bit input of
the Interrupt Status Register via a data demultiplexer, and used
to set that bit high or low as appropriate.
The Interrupt Mask Register has bits corresponding to each of
the Interrupt Status Register Bits. Setting an Interrupt Mask Bit
high forces the corresponding Status Bit output low, while set-
ting an Interrupt Mask Bit low allows the corresponding Status
Bit to be asserted. After masking, the status bits are all OR’d
together to produce the INT output, which will pull low if any
unmasked status bit goes high, i.e., when any measured value
goes out of limit.
The INT output is enabled when Bit 1 of the Configuration Register
(INT_Enable) is high, and Bit 2 (INT_Clear) is low.
The THERM output cannot be cleared nor its interrupt sources
masked.
STATUS
MASK GATING
MASK
BIT
BIT
8
INT_ENABLE
CONFIGURATION
REGISTER
ADM1022
INT_CLEAR
D2–/THERM
INT