LM81CIMT-3/NOPB National Semiconductor, LM81CIMT-3/NOPB Datasheet - Page 4

• Manufacturer Part Number: LM81CIMT-3/NOPB
• Description: IC MONITOR SYS HARDWAR 24-TSSOP
• Manufacturer: National Semiconductor

Specifications of LM81CIMT-3/NOPB

• Function: Hardware Monitor
• Topology: ADC (Sigma Delta), Comparator, Fan Speed Control, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: No
• Voltage - Supply: 2.8 V ~ 3.8 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP
• Supply Voltage Range: 2.8V To 3.8V
• Reset Type: Active-Low
• Supply Current: 1.4mA
• Digital Ic Case Style: TSSOP
• No. Of Pins: 24
• Operating Temperature Range: -40°C To +125°C
• Rohs Compliant: Yes
• Monitored Voltage: 2.5 V , 3.3 V , 5 V , 12 V
• Manual Reset: Not Resettable
• Watchdog: Watchdog
• Battery Backup Switching: No
• Supply Voltage (max): 3.8 V
• Supply Voltage (min): 2.8 V
• Supply Current (typ): 400 uA (Typ)
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM81CIMT-3; *LM81CIMT-3/NOPB; LM81CIMT-3

www.national.com
INT
DACOut/NTEST_IN
RESET
GND
Vccp2
+12Vin
+5Vin
+3.3Vin
+2.5Vin
Vccp1
VID4-VID0
TOTAL PINS
Pin Description
Name(s)
Pin
Number
20-24
Pin
10
11
12
13
14
15
16
17
18
19
(Continued)
Number
of Pins
24
1
1
1
1
1
1
1
1
1
1
5
Digital Output
Analog
Output/Digital
Input
Digital I/O
GROUND
Analog Input
Analog Input
Analog Input
Analog Input
Analog Input
Analog Input
Digital Inputs
Type
Interrupt active low open-drain output. This output is enabled when
Bit 1 in the Configuration Register is set to 1. The default state is
disabled.
0V to +1.25V amplitude 8-bit DAC output. When forced high by an
external voltage the NAND Tree Test mode is enabled which
provides board-level connectivity testing. Refer to Section 11.0 on
NAND Tree testing.
Master Reset, 5 mA driver (open-drain), active low output with a
20 ms minimum pulse width. Available when enabled via Bit 4 in
the Configuration register. It acts as an active low power on
RESET input.
Internally connected to all circuitry. The ground reference for all
analog inputs and the DAC output. This pin needs to be
connected to a low noise analog ground plane for optimum
performance of the DAC output.
Analog input for monitoring −12V or Vccp2. Selectable by
choosing the appropriate external resistor divider values such that
the input to the LM81 is scaled to +2.5V. See Section 4.0.
Analog input for monitoring +12V.
Analog input for monitoring +5V.
Analog input for monitoring +3.3V.
Analog input for monitoring +2.5V.
Analog input for monitoring Vccp, a processor voltage that is
nominally at +2.5V.
Supply Voltage readouts from the Pentium/PRO power supplies
that indicate the operating voltage or the processor (e.g. 1.5V to
2.9V). The values are read in the VID/Fan Divisor Register and
the VID4 Register.
4
Description