NSC LM94CIMT

LM94
TruTherm™ Hardware Monitor with PI Loop Fan Control
for Server Management
1.0 General Description
The LM94 hardware monitor has a two wire digital interface
compatible with SMBus 2.0. Using a Σ∆ ADC, the LM94
measures the temperature of four remote diode connected
transistors as well as its own die and 16 power supply
voltages. The LM94 has new TruTherm technology that supports precision thermal diode measurements of processors
on sub-micron processes.
To set fan speed, the LM94 has two PWM outputs that are
each controlled by up to six temperature zones. The fancontrol algorithm can be based on a lookup table, PI
(proportional/integral) control loop, or a combination of both.
The LM94 includes digital filters that can be invoked to
smooth temperature readings for better control of fan speed
such that acoustical noise is minimized. The LM94 has four
tachometer inputs to measure fan speed. Limit and status
registers for all measured values are included.
The LM94 builds upon the functionality of previous motherboard server management ASICs, such as the LM93. It also
adds measurement and control support for dynamic Vccp
monitoring for VRD10/11 and PROCHOT. It is designed to
monitor a dual processor Xeon class motherboard with a
minimum of external components.
2.0 Features
n
n
n
n
n
n
n
n
n
n
n
n
8-bit Σ∆ ADC
Monitors 16 power supplies
Monitors 4 remote thermal diodes and 2 LM60
New TruTherm technology support for precision thermal
diode measurements
Internal ambient temperature sensing
Programmable autonomous fan control based on
temperature readings with fan boost support
Fan boost support on tachometer limit error event
Fan control based on 13-step lookup table or PI Control
Loop or combination of both
PI fan control loop supports Tcontrol
Temperature reading digital filters
0.5˚C digital temperature sensor resolution
0.0625˚C filtered temperature resolution for fan control
n 2 PWM fan speed control outputs
n 4 fan tachometer inputs
n Dual processor thermal throttling (PROCHOT)
monitoring
n Dual dynamic VID monitoring (6/7 VIDs per processor)
supports VRD10.2/11
n 8 general purpose I/Os:
— 4 can be configured as fan tachometer inputs
— 2 can be configured to connect to processor
THERMTRIP
— 2 are standard GPIOs that could be used to monitor
IERR signal
n 2 general purpose inputs that can be used to monitor
the 7th VID signal for VRD11
n Limit register comparisons of all monitored values
n 2-wire serial digital interface, SMBus 2.0 compliant
— Supports byte/block read and write
— Selectable slave address (tri-level pin selects 1 of 3
possible addresses)
— ALERT output supports interrupt or comparator
modes
n 2.5V reference voltage output
n 56-pin TSSOP package
n XOR-tree test mode
3.0 Key Specifications
Voltage Measurement Accuracy
Temperature Resolution
Temperature Sensor Accuracy
Temperature Range:
— LM94 Operational
— Remote Temp Accuracy
n Power Supply Voltage
n Power Supply Current
n
n
n
n
± 2% FS (max)
9-bits, 0.5˚C
± 2.5 ˚C (max)
0˚C to +85˚C
0˚C to +125˚C
+3.0V to +3.6V
1.6 mA
4.0 Applications
n Servers
n Workstations
n Multi-processor based equipment
5.0 Ordering Information
Order Number NS Package Number Transport media
LM94CIMT
MTD56
34 units in rail
LM94CIMTX
MTD56
1000 units in tape-and-reel
I2C is a registered trademark of the Philips Corporation.
© 2006 National Semiconductor Corporation
DS201124
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LM94 TruTherm™ Hardware Monitor with PI Loop Fan Control for Server Management
April 2006
LM94
6.0 Block Diagram
The block diagram of LM94 hardware is illustrated below. The hardware implementation is a
single chip ASIC solution.
20112401
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LM94
7.0 Application
Baseboard management of a dual processor server. Two
LM94s may be required to manage a quad processor board.
The system diagram below shows a dual processor server
2 Way Xeon Server Management
20112405
3
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LM94
8.0 Connection Diagram
56 Pin TSSOP
20112402
NS Package MTD56
Top View
NS Order Numbers:
LM94CIMT (34 units per rail), or
LM94CIMTX (1000 units per tape-and-reel)
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4
LM94
9.0 Pin Descriptions
Symbol
Pin #
Type
Function
GPIO_0/TACH1
1
Digital I/O
(Open-Drain)
Can be configured as fan tach input or a general purpose
open-drain digital I/O.
GPIO_1/TACH2
2
Digital I/O
(Open-Drain)
Can be configured as fan tach input or a general purpose
open-drain digital I/O.
GPIO_2/TACH3
3
Digital I/O
(Open-Drain)
Can be configured as fan tach input or a general purpose
open-drain digital I/O.
GPIO_3/TACH4
4
Digital I/O
(Open-Drain)
Can be configured as fan tach input or a general purpose
open-drain digital I/O..
GPIO_4 /
P1_THERMTRIP
5
Digital I/O
(Open-Drain)
A general purpose open-drain digital I/O. Can be configured to
monitor a CPU’s THERMTRIP signal to mask other errors. Supports
TTL input logic levels and AGTL compatible input logic levels.
GPIO_5 /
P2_THERMTRIP
6
Digital I/O
(Open-Drain)
A general purpose open-drain digital I/O. Can be configured to
monitor a CPU’s THERMTRIP signal to mask other errors. Supports
TTL input logic levels and AGTL compatible input logic levels.
GPIO_6
7
Digital I/O
(Open-Drain)
Can be used to detect the state of CPU1 IERR or a general purpose
open-drain digital I/O. Supports TTL input logic levels and AGTL
compatible input logic levels.
GPIO_7
8
Digital I/O
(Open-Drain)
Can be used to detect the state of CPU2 IERR or a general purpose
open-drain digital I/O. Supports TTL input logic levels and AGTL
compatible input logic levels.
VRD1_HOT
9
Digital Input
CPU1 voltage regulator HOT. Supports TTL input logic levels and
AGTL compatible input logic levels.
VRD2_HOT
10
Digital Input
CPU2 voltage regulator HOT. Supports TTL input logic levels and
AGTL compatible input logic levels.
P2_VID6/GPI8
11
Digital Input
CPU2 VID6 input. Could also be used as a general purpose input to
trigger an error event. Supports TTL input logic levels and AGTL
compatible input logic levels.
P1_VID6/GPI9
12
Digital Input
CPU1 VID6 input. Could also be used as a general purpose input to
trigger an error event. Supports TTL input logic levels and AGTL
compatible input logic levels.
SMBDAT
13
Digital I/O
(Open-Drain)
Bidirectional System Management Bus Data. Output configured as
5V tolerant open-drain. SMBus 2.0 compliant.
SMBCLK
14
Digital Input
System Management Bus Clock. Driven by an open-drain output,
and is 5V tolerant. SMBus 2.0 Compliant.
ALERT/XtestOut
15
Digital Output
(Open-Drain)
Open-drain ALERT output used in an interrupt driven system to
signal that an error event has occurred. Masked error events do not
activate the ALERT output. When in XOR tree test mode, functions
as XOR Tree output.
RESET
16
Digital I/O
(Open-Drain)
Open-drain reset output when power is first applied to the LM94.
Used as a reset for devices powered by 3.3V stand-by. After reset,
this pin becomes a reset input. If this pin is not used, connection to
an external resistive pull-up is required to prevent LM94 malfunction.
AGND
17
GROUND Input
Analog Ground. Digital ground and analog ground need to be tied
together at the chip then both taken to a low noise system ground.
A voltage difference between analog and digital ground may cause
erroneous results.
VREF
18
Analog Output
2.5V used for external ADC reference, or as a VREF reference
voltage
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LM94
9.0 Pin Descriptions
(Continued)
Symbol
Pin #
Type
Function
REMOTE1−
19
Remote Thermal
Diode_1- Input (CPU
1 THERMDC)
This is the negative input (current sink) from both of the CPU1
thermal diodes. Connected to THERMDC pin of Pentium processor
or the emitter of a diode connected MMBT3904 NPN transistor.
Serves as the negative input into the A/D for thermal diode voltage
measurements. A 100 pF capacitor is optional and can be
connected between REMOTE1− and REMOTE1+.
REMOTE1a+
20
Remote Thermal
Diode_1+ I/O (CPU1
THERMDA1)
This is a positive connection to the first CPU1 thermal diode. Serves
as the positive input into the A/D for thermal diode voltage
measurements. It also serves as a current source output that
forward biases the thermal diode. Connected to THERMDA pin of
Pentium processor or the base of a diode connected MMBT3904
NPN transistor. A 100 pF capacitor is optional and can be
connected between REMOTE1− and each REMOTE1+.
REMOTE2−
21
Remote Thermal
Diode_2 - Input
(CPU2 THERMDC)
This is the negative input (current sink) from both of the CPU2
thermal diodes. Connected to THERMDC pins of Pentium processor
or the emitter of a diode connected MMBT3904 NPN transistor.
Serves as the negative input into the A/D for thermal diode voltage
measurements. A 100 pF capacitor is optional and can be
connected between REMOTE2− and each REMOTE2+.
REMOTE2a+
22
Remote Thermal
Diode_2 + I/O (CPU2
THERMDA1)
This is a positive connection to the first CPU2 thermal diode. Serves
as the positive input into the A/D for thermal diode voltage
measurements. It also serves as a current source output that
forward biases the thermal diode. Connected to THERMDA pin of
Pentium processor or the base of a diode connected MMBT3904
NPN transistor. A 100 pF capacitor is optional and can be
connected between REMOTE2− and REMOTE2+.
AD_IN1/REMOTE1b+
23
Analog Input (+12V1
or CPU1
THERMDA2)
Analog Input for +12V Rail 1 monitoring, for CPU1 voltage regulator.
External attenuation resistors required such that 12V is attenuated
to 0.927V for nominal 3⁄4 scale reading. This pin may also serve as
the second positive thermal diode input for CPU1.
AD_IN2/REMOTE2b+
24
Analog Input (+12V2
or CPU2
THERMDA2)
Analog Input for +12V Rail 2 monitoring, for CPU2 voltage regulator.
External attenuation resistors required such that 12V is attenuated
to 0.927V for nominal 3⁄4 scale reading. This pin may also serve as
the second positive thermal diode input for CPU2.
AD_IN3
25
Analog Input (+12V3)
Analog Input for +12V Rail 3, for Memory/3GIO slots. External
attenuation resistors required such that 12V is attenuated to 0.927V
for nominal 3⁄4 scale reading.
AD_IN4
26
Analog Input
(FSB_Vtt)
Analog input for 1.2V monitoring, nominal 3⁄4 scale reading
AD_IN5
27
Analog Input (3GIO /
PXH / MCH_Core)
Analog input for 1.5V monitoring, nominal 3⁄4 scale reading
AD_IN6
28
Analog Input
(ICH_Core)
Analog input for 1.5V monitoring, nominal 3⁄4 scale reading
AD_IN7 (P1_Vccp)
29
Analog Input
(CPU1_Vccp)
Analog input for +Vccp (processor voltage) monitoring.
AD_IN8 (P2_Vccp)
30
Analog Input
(CPU2_Vccp)
Analog input for +Vccp (processor voltage) monitoring.
AD_IN9
31
Analog Input (+3.3V)
Analog input for +3.3V monitoring, nominal 3⁄4 scale reading
AD_IN10
32
Analog Input (+5V)
Analog input for +5V monitoring silver box supply monitoring,
nominal 3⁄4 scale reading
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LM94
9.0 Pin Descriptions
(Continued)
Symbol
Pin #
Type
Function
AD_IN11
33
Analog Input
(SCSI_Core)
Analog input for +2.5V monitoring, nominal 3⁄4 scale reading. This
pin may also be used to monitor an analog temperature sensor such
as the LM60, since readings from this input can be routed to the fan
control logic.
AD_IN12
34
Analog Input
(Mem_Core)
Analog input for +1.969V monitoring, nominal 3⁄4 scale reading.
AD_IN13
35
Analog Input
(Mem_Vtt)
Analog input for +0.984V monitoring, nominal 3⁄4 scale reading.
AD_IN14
36
Analog Input
(Gbit_Core)
Analog input for +0.984V S/B monitoring, nominal 3⁄4 scale reading.
AD_IN15
37
Analog Input (-12V)
Analog input for -12V monitoring. External resistors required to scale
to positive level. Full scale reading at 1.236V, , nominal 3⁄4 scale
reading. This pin may also be used to monitor an analog
temperature sensor such as the LM60, since readings from this
input can be routed to the fan control logic.
Address Select
38
3 level analog input
This input selects the lower two bits of the LM94 SMBus slave
address.
3.3V SB (AD_IN16)
39
POWER (VDD) +3.3V
standby power
VDD power input for LM94. Generally this is connected to +3.3V
standby power.
The LM94 can be powered by +3.3V if monitoring in low power
states is not required, but power should be applied to this input
before any other pins.
This pin also serves as the analog input to monitor the 3.3V
stand-by (SB) voltage. It is necessary to bypass this pin with a 0.1
µF in parallel with 100 pF. A bulk capacitance of 10 µF should be in
the near vicinity. The 100 pF should be closest to the power pin.
GND
40
GROUND
Digital Ground. Digital ground and analog ground need to be tied
together at the chip then both taken to a low noise system ground.
A voltage difference between analog and digital ground may cause
erroneous results.
PWM1
41
Digital Output
(Open-Drain)
Fan control output 1.
PWM2
42
Digital Output
(Open-Drain)
Fan control output 2
P1_VID0/P1_VID7
43
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P1_VID1
44
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P1_VID2
45
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P1_VID3
46
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P1_VID4
47
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P1_VID5
48
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P1_PROCHOT
49
Digital I/O
(Open-Drain)
Connected to CPU1 PROCHOT (processor hot) signal through a
bidirectional level shifter. Supports TTL input logic levels and AGTL
compatible input logic levels.
P2_PROCHOT
50
Digital I/O
(Open-Drain)
Connected to CPU2 PROCHOT (processor hot) signal through a
bidirectional level shifter. Supports TTL input logic levels and AGTL
compatible input logic levels.
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LM94
9.0 Pin Descriptions
(Continued)
Symbol
Pin #
Type
Function
P2_VID0/P2_VID7
51
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P2_VID1
52
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P2_VID2
53
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P2_VID3
54
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P2_VID4
55
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
P2_VID5
56
Digital Input
Voltage Identification signal from the processor. Supports TTL input
logic levels and AGTL compatible input logic levels.
The over-score indicates the signal is active low (“Not”).
10.0 Recommended Implementation
20112406
Recommended implementation without thermal diode connections
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LM94
10.0 Recommended Implementation
(Continued)
20112407
Note: 100 pF cap across each thermal diode is optional and should be placed close to the LM94, if used. The maximum capacitance between thermal diode
pins is 300 pF.
Thermal diode recommended implementation
All but 4 of the analog inputs include internal scaling resistors. External scaling resistors are required for measuring
± 12V. The inputs are converted to 8-bit digital values such
that a nominal voltage appears at 3⁄4 scale for positive voltages and 1⁄4 scale for negative voltages. The analog inputs
are intended to be connected to both baseboard resident
VRDs and to standard voltage rails supplied by a SSI compliant power supply.
11.0 Functional Description
The LM94 provides 16 channels of voltage monitoring, 4
remote thermal diode monitors, an internal/local ambient
temperature sensor, 2 PROCHOT monitors, 4 fan tachometers, 8 GPIOs, THERMTRIP monitor for masking error
events, 2 sets of 7 VID inputs, an ALERT output and all the
associated limit registers on a single chip, and communicates to the rest of the baseboard over the System Management Bus (SMBus). The LM94 also provides 2 PWM outputs
and associated fan control logic for controlling the speed of
system fans. There are two sets of fan control logic, a lookup
table and a PI (proportional/integral) loop controller. The
lookup table and PI controller are interactive, such that the
fans run at the fastest required speed. Upon a temperature
or fan tach error event, the PWM outputs may be programmed such that they automatically boost to 100% duty
cycle. A timer is included that sets the minimum time that the
fans are in the boost condition when activated by a fan tach
error.
The LM94 incorporates National Semiconductor’s TruTherm
technology for precision “Remote Diode” readings of processors on 90nm process geometry or smaller. Readings from
the external thermal diodes and the internal temperature
sensor are made available as an 9-bit two’s-complement
digital value with the LSb representing 0.5˚C. Filtered temperature readings are available as a 12-bit two’scomplement digital value with the LSb representing
0.0625˚C.
The LM94 has logic that ties a set of dynamically moving VID
inputs to their associated Vccp analog input for real time
window comparison fault determination. Voltage mapping for
VRD10, VRD10 extended and VRD11are supported by the
LM94. When VRD10 mode is selected GPI8 and GPI9 can
be used to detect external error flags whose state is be
reflected in the status registers.
Error events are captured in two sets of mirrored status
registers (BMC Error Status Registers and Host Status Registers) allowing two controllers access to the status information without any interference.
The LM94’s ALERT output supports interrupt mode or comparator mode of operation. The comparator mode is only
functional for thermal monitoring.
The LM94 provides a number of internal registers, which are
detailed in the register section of this document.
12.0 Please contact your local sales office for complete LM94 applications
information.
13.0 Registers
13.1 REGISTER WARNINGS
In most cases, reserved registers and register bits return zero when read. This should not be relied upon, since reserved registers
can be used for future expansion of the LM94 functions.
Some registers have “N/D” for their default value. This means that the power-up default of the register is not defined. In the case
of value registers, care should be taken to ensure that software does not read a value register until the associated measurement
function has acquired a measurement. This applies to temperatures, voltages, fan RPM, and PROCHOT monitoring.
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LM94
13.0 Registers
(Continued)
13.2 REGISTER SUMMARY TABLE
Register Key
Term
Lock
Register Name
Description
N/D
Not Defined
N/A
Not Applicable
R
Read Only
R/W
Read or Write
RWC
Read or Write to Clear
Address
Description
FACTORY REGISTERS
x
XOR Test
00h
Used to set the XOR test tree mode
SMBus Test
01h
SMBus read/write test register
Reserved
02h-04h
“REMOTE DIODE” MODE SELECT
x
Transistor Mode Select
05h
Selects Diode Mode (default) or Transistor Mode for “Remote
Diode” measurements
Zone 1b (CPU1 Diode b) Temp
06h
Measured value of remote thermal diode temperature channel
1b
Zone 2b (CPU2 Diode b) Temp
07h
Measured value of remote thermal diode temperature channel
2b
Zone 1b (CPU1 Diode b) Filtered
Temp
08h
Filtered value of remote thermal diode temperature channel 1b
Zone 2b (CPU2 Diode b) Fitlered
Temp
09h
Filtered value of remote thermal diode temperature channel 2b
PWM1 8-bit Duty Cycle Value
0Ah
8- bit value of the PWM1 duty cycle.
PWM2 8-bit Duty Cycle Value
0Bh
8-bit value of the PWM2 duty cycle
VALUE REGISTER SECTION 1
HIGH RESOLUTION PWM OVERIDE REGISTERS
x
PWM1 Duty Cycle Override (low
byte)
0Ch
Lower byte of the high resolution PWM1 duty cycle register
x
PWM1 Duty Cycle Override (high
byte)
0Dh
Upper byte of the high resolution PWM1 duty cycle register
x
PWM2 Duty Cycle Override (low
byte)
0Eh
Lower byte of the high resolution PWM2 duty cycle register
x
PWM2 Duty Cycle Override (high
byte)
0Fh
Upper byte of the high resolution PWM2 duty cycle register
EXTENDED RESOLUTION TEMPERATURE VALUE REGISTERS
Z1a_LSB
10h
Zone 1a (CPU1) extended resolution unfiltered temperature
value register, least-significant byte
Z1a_MSB
11h
Zone 1a (CPU1) extended resolution unfiltered temperature
value register, most-significant byte
Z1b_LSB
12h
Zone 1b (CPU1) extended resolution unfiltered temperature
value register, least-significant-byte
Z1b_MSB
13h
Zone 1b (CPU1) extended resolution unfiltered temperature
value register, most-significant byte
Z2a_LSB
14h
Zone 2a (CPU2) extended resolution unfiltered temperature
value register, least-significant-byte
Z2a_MSB
15h
Zone 2a (CPU2) extended resolution unfiltered temperature
value register, most-significant byte
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Lock
LM94
13.0 Registers
(Continued)
Register Name
Address
Description
EXTENDED RESOLUTION TEMPERATURE VALUE REGISTERS
Z2b_LSB
16h
Zone 2b (CPU2) extended resolution unfiltered temperature
value register, least-significant-byte
Z2b_MSB
17h
Zone 2b (CPU2) extended resolution unfiltered temperature
value register, most-significant byte
Z1a_F_LSB
18h
Zone 1a (CPU1) extended resolution filtered temperature value
register, least-significant byte
Z1a_F_MSB
19h
Zone 1a (CPU1) extended resolution filtered temperature value
register, most-significant byte
Z1b_F_LSB
1Ah
Zone 1b (CPU1) extended resolution filtered temperature value
register, least-significant-byte
Z1b_F_MSB
1Bh
Zone 1b (CPU1) extended resolution filtered temperature value
register, most-significant byte
Z2a_F_LSB
1Ch
Zone 2a (CPU2) extended resolution filtered temperature value
register, least-significant-byte
Z2a_F_MSB
1Dh
Zone 2a (CPU2) extended resolution filtered temperature value
register, most-significant byte
Z2b_F_LSB
1Eh
Zone 2b (CPU2) extended resolution filtered temperature value
register, least-significant-byte
Z2b_F_MSB
1Fh
Zone 2b (CPU2) extended resolution filtered temperature value
register, most-significant byte
Z3_LSB
20h
Zone 3 (Internal) extended resolution temperature value
register, least-significant byte
Z3_MSB
21h
Zone 3 (Internal) extended resolution temperature value
register, least-significant byte
Z4_LSB
22h
Zone 4 (External Digital) extended resolution temperature value
register, most-significant byte
Z4_MSB
23h
Zone 4 (External Digital) extended resolution temperature value
register, least-significant byte
Reserved
24h-30h
PI LOOP AND FAN CONTROL SETUP REGISTERS
x
Temperature Source Select
31h
Selects the temperature source for some temperature zones.
x
PWM Filter Settings
32h
Sets the IIR filter coefficients for the PWM outputs for low
resolution sources
x
PWM1 Filter Shutoff Threshold
33h
PWM1 Filter Shutoff Threshold
x
PWM2 Filter Shutoff Threshold
34h
PWM2 Filter Shutoff Threshold
x
PI/LUT Fan Control Bindings
35h
PI/LUT fan control binding configuration
x
PI Controller Minimum PWM and
Hysteresis
36h
PI Controller Minimum PWM and Hysteresis settings
x
Zone 1 Tcontrol
37h
Zone 1 (CPU1) PI Controller Target Temperature (Tcontrol)
x
Zone 2 Tcontrol
38h
Zone 2 (CPU2) PI Controller Target Temperature (Tcontrol)
x
Zone 1 Toff
39h
Zone 1 (CPU1) PI Controller Off Temperature (Toff)
x
Zone 2 Toff
3Ah
Zone 2 (CPU2) PI Controller Off Temperature (Toff)
x
P Coefficient
3Bh
PI controller proportional coefficient
x
I Coefficient
3Ch
PI controller integral coefficient
x
PI Exponents
3Dh
PI controller coefficient exponents
3Eh
Contains manufacturer ID code
DEVICE IDENTIFICATION REGISTERS
Manufacturer ID
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LM94
13.0 Registers
Lock
(Continued)
Register Name
Address
Description
PI LOOP AND FAN CONTROL SETUP REGISTERS
Version/Stepping
3Fh
Contains code for major and minor revisions
B_Error Status 1
40h
BMC error status register 1
B_Error Status 2
41h
BMC error register 2
B_Error Status 3
42h
BMC error register 3
B_Error Status 4
43h
BMC error register 4
B_P1_PROCHOT Error Status
44h
BMC error register for P1_PROCHOT
B_P2_PROCHOT Error Status
45h
BMC error register for P2_PROCHOT
B_GPI Error Status
46h
BMC error register for GPIs
B_Fan Error Status
47h
BMC error register for Fans
H_Error Status 1
48h
HOST error status register 1
H_Error Status 2
49h
HOST error register 2
H_Error Status 3
4Ah
HOST error register 3
H_Error Status 4
4Bh
HOST error register 4
H_P1_PROCHOT Error Status
4Ch
HOST error register for P1_PROCHOT
BMC ERROR STATUS REGISTERS
HOST ERROR STATUS REGISTERS
H_P2_PROCHOT Error Status
4Dh
HOST error register for P2_PROCHOT
H_GPI Error Status
4Eh
HOST error register for GPIs
H_Fan Error Status
4Fh
HOST error register for Fans
Zone 1a (CPU1) Temp
50h
Measured value of remote thermal diode temperature channel
1a
Zone 2a (CPU2) Temp
51h
Measured value of remote thermal diode temperature channel
2a
VALUE REGISTERS SECTION 2
Zone 3 (Internal) Temp
52h
Measured temperature from on-chip sensor
Zone 4 (External Digital) Temp
53h
Measured temperature from external temperature sensor
Zone 1a (CPU1) Filtered Temp
54h
Filtered value of remote thermal diode temperature channel 1a
Zone 2a (CPU2) Filtered Temp
55h
Filtered value of remote thermal diode temperature channel 2a
AD_IN1 Voltage
56h
Measured value of AD_IN1
AD_IN2 Voltage
57h
Measured value of AD_IN2
AD_IN3 Voltage
58h
Measured value of AD_IN3
AD_IN4 Voltage
59h
Measured value of AD_IN4
AD_IN5 Voltage
5Ah
Measured value of AD_IN5
AD_IN6 Voltage
5Bh
Measured value of AD_IN6
AD_IN7 Voltage
5Ch
Measured value of AD_IN7
AD_IN8 Voltage
5Dh
Measured value of AD_IN8
AD_IN9 Voltage
5Eh
Measured value of AD_IN9
AD_IN10 Voltage
5Fh
Measured value of AD_IN10
AD_IN11 Voltage
60h
Measured value of AD_IN11
AD_IN12 Voltage
61h
Measured value of AD_IN12
AD_IN13 Voltage
62h
Measured value of AD_IN13
AD_IN14 Voltage
63h
Measured value of AD_IN14
AD_IN15 Voltage
64h
Measured value of AD_IN15
AD_IN16 Voltage
65h
Measured value of AD_IN16 (VDD 3.3V S/B)
Reserved
66h
Current P1_PROCHOT
67h
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Measured P1_PROCHOT throttle percentage
12
Lock
LM94
13.0 Registers
(Continued)
Register Name
Address
Description
VALUE REGISTERS SECTION 2
Average P1_PROCHOT
68h
Average P1_PROCHOT throttle percentage
Current P2_PROCHOT
69h
Measured P2_PROCHOT throttle percentage
Average P2_PROCHOT
6Ah
Average P2_PROCHOT throttle percentage
GPI State
6Bh
Current GPIO state
P1_VID
6Ch
Current VID value of Processor 1
P2_VID
6Dh
Current VID value of Processor 2
FAN Tach 1 LSB
6Eh
Measured FAN Tach 1 LSB
FAN Tach 1 MSB
6Fh
Measured FAN Tach 1 MSB
FAN Tach 2 LSB
70h
Measured FAN Tach 2 LSB
FAN Tach 2 MSB
71h
Measured FAN Tach 2 MSB
FAN Tach 3 LSB
72h
Measured FAN Tach 3 LSB
FAN Tach 3 MSB
73h
Measured FAN Tach 3 MSB
FAN Tach 4 LSB
74h
Measured FAN Tach 4 LSB
FAN Tach 4 MSB
75h
Measured FAN Tach 4 MSB
Reserved
76h-77h
TEMPERATURE LIMIT REGISTERS
Zone 1 (CPU1) Low Temp
78h
Low limit for external thermal diode temperature channel 1 (D1)
measurement
Zone 1 (CPU1) High Temp
79h
High limit for external thermal diode temperature channel 1
(D1) measurement
Zone 2 (CPU2) Low Temp
7Ah
Low limit for external thermal diode temperature channel 2 (D2)
measurement
Zone 2 (CPU2) High Temp
7Bh
High limit for external thermal diode temperature channel 2
(D2) measurement
Zone 3 (Internal) Low Temp
7Ch
Low limit for local temperature measurement
Zone 3 (Internal) High Temp
7Dh
High limit for local temperature measurement
Zone 4 (External Digital) Low Temp
7Eh
Low limit for external digital temperature sensor
Zone 4 (External Digital) High Temp
7Fh
High limit for external digital temperature sensor
x
Fan Boost Temp Zone 1
80h
Zone 1 (CPU1) fan boost temperature
x
Fan Boost Temp Zone 2
81h
Zone 2 (CPU2) fan boost temperature
x
Fan Boost Temp Zone 3
82h
Zone 3 (Internal) fan boost temperature
x
Fan Boost Temp Zone 4
83h
Zone 4 (External Digital) fan boost temperature
Zone1 and Zone 2 Hysteresis
84h
Zone 1 and Zone 2 hysteresis for limit comparisons
Zone 3 and Zone 4 Hysteresis
85h
Zone 3 and Zone 4 hysteresis for limit comparisons
Reserved
86h-8Dh
ZONE 1b and 2b TEMPERATURE READING ADJUSTMENT REGISTERS
Zone 1b Temp Adjust
8Eh
Allows all Zone 1b temperature measurements to be adjusted
by a programmable offset.
Zone 2b Temp Adjust
8Fh
Allows all Zone 2b temperature measurements to be adjusted
by a programmable offset.
13
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LM94
13.0 Registers
Lock
(Continued)
Register Name
Address
Description
OTHER LIMIT REGISTERS
AD_IN1 Low Limit
90h
Low limit for analog input 1 measurement
AD_IN1 High Limit
91h
High limit for analog input 1 measurement
AD_IN2 Low Limit
92h
Low limit for analog input 2 measurement
AD_IN2 High Limit
93h
High limit for analog input 2 measurement
AD_IN3 Low Limit
94h
Low limit for analog input 3 measurement
AD_IN3 High Limit
95h
High limit for analog input 3 measurement
AD_IN4 Low Limit
96h
Low limit for analog input 4 measurement
AD_IN4 High Limit
97h
High limit for analog input 4 measurement
AD_IN5 Low Limit
98h
Low limit for analog input 5 measurement
AD_IN5 High Limit
99h
High limit for analog input 5 measurement
AD_IN6 Low Limit
9Ah
Low limit for analog input 6 measurement
AD_IN6 High Limit
9Bh
High limit for analog input 6 measurement
AD_IN7 Low Limit
9Ch
Low limit for analog input 7 measurement
AD_IN7 High Limit
9Dh
High limit for analog input 7 measurement
AD_IN8 Low Limit
9Eh
Low limit for analog input 8 measurement
AD_IN8 High Limit
9Fh
High limit for analog input 8 measurement
AD_IN9 Low Limit
A0h
Low limit for analog input 9 measurement
AD_IN9 High Limit
A1h
High limit for analog input 9 measurement
AD_IN10 Low Limit
A2h
Low limit for analog input 10 measurement
AD_IN10 High Limit
A3h
High limit for analog input 10 measurement
AD_IN11 Low Limit
A4h
Low limit for analog input 11 measurement
AD_IN11 High Limit
A5h
High limit for analog input 11 measurement
AD_IN12 Low Limit
A6h
Low limit for analog input 12 measurement
AD_IN12 High Limit
A7h
High limit for analog input 12 measurement
AD_IN13 Low Limit
A8h
Low limit for analog input 13 measurement
AD_IN13 High Limit
A9h
High limit for analog input 13 measurement
AD_IN14 Low Limit
AAh
Low limit for analog input 14 measurement
AD_IN14 High Limit
ABh
High limit for analog input 14 measurement
AD_IN15 Low Limit
ACh
Low limit for analog input 15 measurement
AD_IN15 High Limit
ADh
High limit for analog input 15 measurement
AD_IN16 Low Limit
AEh
Low limit for analog input 16 measurement
AD_IN16 High Limit
AFh
High limit for analog input 16 measurement
P1_PROCHOT User Limit
B0h
User settable limit for P1_PROCHOT
P2_PROCHOT User Limit
B1h
User settable limit for P2_PROCHOT
Vccp1 Limit Offsets
B2h
VID offset values for window comparator for CPU1 Vccp
(AD_IN7)
Vccp2 Limit Offsets
B3h
VID offset values for window comparator for CPU2 Vccp
(AD_IN8)
FAN Tach 1 Limit LSB
B4h
FAN Tach 1 Limit LSB
FAN Tach 1 Limit MSB
B5h
FAN Tach 1 Limit MSB
FAN Tach 2 Limit LSB
B6h
FAN Tach 2 Limit LSB
FAN Tach 2 Limit MSB
B7h
FAN Tach 2 Limit MSB
FAN Tach 3 Limit LSB
B8h
FAN Tach 3 Limit LSB
FAN Tach 3 Limit MSB
B9h
FAN Tach 3 Limit MSB
FAN Tach 4 Limit LSB
BAh
FAN Tach 4 Limit LSB
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14
Lock
LM94
13.0 Registers
(Continued)
Register Name
Address
Description
OTHER LIMIT REGISTERS
FAN Tach 4 Limit MSB
BBh
FAN Tach 4 Limit MSB
Special Function Control 1
BCh
Controls the hysteresis for voltage limit comparisons. Also
selects filtered or unfiltered temperature usage for temperature
limit comparisons and fan control.
Special Function Control 2
BDh
Enables smart tach detection. Also selects 0.5˚C or 1.0˚C
resolution for fan control.
x
GPI / VID Level Control
BEh
Control the input threshold levels for the P1_VIDx, P2_VIDx
and GPIO_x inputs.
x
PWM Ramp Control
BFh
Controls the ramp rate of the PWM duty cycle when
VRDx_HOT is asserted, as well as the ramp rate when
PROCHOT exceeds the user threshold.
x
Fan Boost Hysteresis (Zones 1/2)
C0h
Fan Boost Hysteresis for zones 1 and 2
x
Fan Boost Hysteresis (Zones 3/4)
C1h
Fan Boost Hysteresis for zones 3 and 4
x
Zones 1/2 Spike Smoothing Control
C2h
Configures Spike Smoothing for zones 1 and 2
x
LUT 1/2 MinPWM and Hysteresis
C3h
Controls MinPWM and hysteresis setting for LUT 1 and 2
auto-fan control
x
LUT 3/4 MinPWM and Hysteresis
C4h
Controls MinPWM and hysteresis setting for LUT 3 and 4
auto-fan control
GPO
C5h
Controls the output state of the GPIO pins
SETUP REGISTERS
PROCHOT Control
C6h
Controls assertion of P1_PROCHOT or P2_PROCHOT
PROCHOT Time Interval
C7h
Configures the time window over which the PROCHOT inputs
are measured
x
PWM1 Control 1
C8h
Controls PWM control source bindings.
x
PWM1 Control 2
C9h
Controls PWM override and output polarity
x
PWM1 Control 3
CAh
Controls PWM spin-up duration and duty cycle
x
PWM1 Control 4
CBh
Frequency control for PWM1.
x
PWM2 Control 1
CCh
Controls PWM control source bindings.
x
PWM2 Control 2
CDh
Controls PWM override and output polarity
x
PWM2 Control 3
CEh
Controls PWM spin-up duration and duty cycle
x
PWM2 Control 4
CFh
Frequency control for PWM2
x
LUT 1 Base Temperature
D0h
Base temperature to which look-up table offset is applied for
LUT 1
x
LUT 2 Base Temperature
D1h
Base temperature to which look-up table offset is applied for
LUT 2
x
LUT 3 Base Temperature
D2h
Base temperature to which look-up table offset is applied for
LUT 3
x
LUT 4 Base Temperature
D3h
Base temperature to which look-up table offset is applied for
LUT 4
x
Step 2 Temp Offset
D4h
Step 2 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 3 Temp Offset
D5h
Step 3 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 4 Temp Offset
D6h
Step 4 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 5 Temp Offset
D7h
Step 5 LUT 1/2 and LUT 3/4 Offset Temperatures
15
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LM94
13.0 Registers
Lock
(Continued)
Register Name
Address
Description
SETUP REGISTERS
x
Step 6 Temp Offset
D8h
Step 6 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 7 Temp Offset
D9h
Step 7 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 8 Temp Offset
DAh
Step 8 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 9 Temp Offset
DBh
Step 9 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 10 Temp Offset
DCh
Step 10 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 11 Temp Offset
DDh
Step 11 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 12 Temp Offset
DEh
Step 12 LUT 1/2 and LUT 3/4 Offset Temperatures
x
Step 13 Temp Offset
DFh
Step 13 LUT 1/2 and LUT 3/4 Offset Temperatures
TACH to PWM Binding
E0h
Controls the tachometer input to PWM output binding
x
Tach Boost Control
E1h
Controls the fan boost function upon a tach error
x
LM94 Status/Control
E2h
Gives Master error status, ASF reset control and Max PWM
control
x
LM94 Configuration
E3h
Configures various outputs and provides START bit
SLEEP STATE CONTROL AND MASK REGISTERS
Sleep State Control
E4h
Used to communicate the system sleep state to the LM94
S1 GPI Mask
E5h
Sleep state S1 GPI error mask register
S1 Fan Mask
E6h
Sleep state S1 fan tach error mask register
S3 GPI Mask
E7h
Sleep state S3 GPI error mask register
S3 Fan Mask
E8h
Sleep state S3 fan tach error mask register
S3 Temperature/Voltage Mask
E9h
Sleep state S3 temperature or voltage error mask register
S4/5 GPI Mask
EAh
Sleep state S4/5 GPI error mask register
S4/5 Temperature/Voltage Mask
EBh
Sleep state S4/5 temperature or voltage error mask register
OTHER MASK REGISTERS
GPI Error Mask
ECh
Error mask register for GPI faults
Miscellaneous Error Mask
EDh
Error mask register for VRDx_HOT, GPI, and dynamic Vccp
limit checking.
ZONE 1a AND 2a TEMPERATURE READING ADJUSTMENT REGISTERS
Zone 1a Temp Adjust
EEh
Allows all Zone 1a temperature measurements to be adjusted
by a programmable offset
Zone 2a Temp Adjust
EFh
Allows all Zone 2a temperature measurements to be adjusted
by a programmable offset
Block Write Command
F0h
SMBus Block Write Command Code
Block Read Command
F1h
SMBus Block Write/Read Process call
Fixed Block 0
F2h
Fixed block code address 40h, size 8 bytes
Fixed Block 1
F3h
Fixed block code address 48h, size 8 bytes
Fixed Block 2
F4h
Fixed block code address 50h, size 6 bytes
Fixed Block 3
F5h
Fixed block code address 56h, size 16 bytes
Fixed Block 4
F6h
Fixed block code address 67h, size 4 bytes
Fixed Block 5
F7h
Fixed block code address 6Eh, size 8 bytes
Fixed Block 6
F8h
Fixed block code address 78h, size 12 bytes
Fixed Block 7
F9h
Fixed block code address 90h, size 32 bytes
Fixed Block 8
FAh
Fixed block code address B4h, size 8 bytes
Fixed Block 9
FBh
Fixed block code address C8h, size 8 bytes
Fixed Block 10
FCh
Fixed block code address D0h, size 16 bytes
BLOCK COMMANDS
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16
Lock
LM94
13.0 Registers
(Continued)
Register Name
Address
Description
BLOCK COMMANDS
Fixed Block 11
FDh
Fixed block code address E5h, size 9 bytes
Reserved
FEh-FFh
Reserved for future commands
Please contact your local sales office for complete LM94 applications information.
17
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LM94
14.0 Absolute Maximum
Ratings (Notes 1, 2)
ESD Susceptibility (Note 4)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Positive Supply Voltage (VDD)
300V
Charged Device Model
750V
−65˚C to +150˚C
Soldering process must comply with National’s
reflow temperature profile specifications. Refer to
www.national.com/packaging/. (Note 5)
−0.3V to 6.0V
(Except Analog
Inputs)
Voltage on +5V Input
3 kV
Machine Model
Storage Temperature
6.0V
Voltage on Any Digital Input or
Output Pin
Human Body Model
15.0 Operating Ratings (Notes 1, 2)
−0.3V to +6.667V
Voltage at Positive Remote
Diode Inputs, AD_IN1, AD_IN2,
AD_IN3, and AD_IN15 Inputs −0.3V to (VDD + 0.05V)
TMIN ≤ TA ≤ TMAX
0˚C ≤ TA ≤ +85˚C
Operating Temperature Range
Nominal Supply Voltage
Voltage at Other Analog Voltage
Inputs
3.3V
Supply Voltage Range (VDD)
−0.3V to +6.0V
+3.0V to +3.6V
VID0-VID5
Input Current at Thermal Diode
Negative Inputs
Input Current at any pin (Note 3)
± 1 mA
± 10mA
Package Input Current (Note 3)
± 100 mA
Maximum Junction Temperature
(Note 9)
(TJMAX)
150 ˚C
−0.05V to +5.5V
Digital Input Voltage Range
−0.05V to
(VDD + 0.05V)
Package Thermal Resistance
(Note 6)
79˚C/W
DC Electrical Characteristics
The following limits apply for +3.0 VDC to +3.6 VDC, unless otherwise noted. Bold face limits apply for TA = TJ over TMIN to
TMAX of the operating range; all other limits TA = TJ = 25˚C unless otherwise noted. TA is the ambient temperature of the
LM94; TJ is the junction temperature of the LM94; TD is the junction temperature of the thermal diode.
Symbol
Parameter
Typical
(Note 9)
Limits
(Note 10)
Units
(Limits)
Converting, Interface and
Fans Inactive, Peak
Current
2
2.75
mA (max)
Converting, Interface and
Fans Inactive, Average
Current
1.6
Conditions
POWER SUPPLY CHARACTERISTICS
Power Supply Current
Power-On Reset Threshold Voltage
2
mA
1.6
V (min)
2.7
V (max)
±3
± 2.5
˚C (max)
TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICS
0˚C ≤ TA ≤ 85˚C
Local Temperature Accuracy Over Full Range
TA = +55˚C
Local Temperature Resolution
1
0˚C ≤ TA ≤ 85˚C
and 0˚C ≤ TD ≤ 100˚C
Remote Thermal Diode Temperature Accuracy
Over Full Range; targeted for a typical Pentium
processor on 90 nm or 65 nm process(Note 8)
0˚C ≤ TA ≤ 85˚C
and TD =70˚C
Remote Thermal Diode Temperature Accuracy;
targeted for a typical Pentium processor on 90nm
or 65nm process (Note 8)
0˚C ≤ TA ≤ 85˚C
and 25˚C ≤ TD ≤ 70˚C
±1
High Level
172
Low Level
10.75
Remote Temperature Resolution
Thermal Diode Current Ratio
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˚C (max)
˚C
±3
˚C (max)
± 2.5
˚C (max)
˚C
1
Thermal Diode Source Current
TC
±2
±1
˚C
230
µA (max)
µA
16
Total Monitoring Cycle Time
100
18
ms (max)
(Continued)
The following limits apply for +3.0 VDC to +3.6 VDC, unless otherwise noted. Bold face limits apply for TA = TJ over TMIN to
TMAX of the operating range; all other limits TA = TJ = 25˚C unless otherwise noted. TA is the ambient temperature of the
LM94; TJ is the junction temperature of the LM94; TD is the junction temperature of the thermal diode.
Symbol
Parameter
Conditions
Typical
(Note 9)
Limits
(Note 10)
Units
(Limits)
±2
% of
FS (max)
ANALOG-TO-DIGITAL VOLTAGE MEASUREMENT CONVERTER CHARACTERISTICS
TUE
Total Unadjusted Error (Note 12)
DNL
Differential Non-Linearity
PSS
Power Supply (VDD) Sensitivity
TC
Total Monitoring Cycle Time
Input Resistance for Inputs with Dividers
±1
LSB
±1
%/V (of
FS)
200
AD_IN1- AD_IN3 and AD_IN15 Analog Input
Leakage Current (Note 13)
100
ms (max)
140
kΩ (min)
60
nA (max)
±1
% (max)
2.525
2.475
V (max)
V (min)
REFERENCE OUTPUT (VREF) CHARACTERISTICS
Tolerance
VREF
Output Voltage (Note 14)
2.500
ISOURCE = −2 mA
ISINK = 2 mA
Load Regulation
0.1
%
DIGITAL OUTPUTS: PWM1, PWM2
IOL
Maximum Current Sink
VOL
Output Low Voltage
8
mA (min)
IOUT = 8.0 mA
0.4
V (max)
IOUT = 4.0 mA
0.4
V (min)
IOUT = 6 mA
0.55
V (min)
10
µA (max)
32
mA (max)
DIGITAL OUTPUTS: ALL
VOL
Output Low Voltage (Note excessive current flow
causes self-heating and degrades the internal
temperature accuracy.)
IOH
High Level Output Leakage Current
IOTMAX
Maximum Total Sink Current for all Digital Outputs
Combined
VOUT = VDD
CO
Digital Output Capacitance
0.1
20
pF
DIGITAL INPUTS: ALL
VIH
Input High Voltage Except Address Select
2.1
V (min)
VIL
Input Low Voltage Except Address Select
0.8
V (max)
VIH
Input High Voltage for Address Select
90% VDD
V (min)
VIM
Input Mid Voltage for Address Select
43% VDD
57% VDD
V (min)
V (max)
10% VDD
V (max)
VIL
Input Low Voltage for Address Select
VHYST
DC Hysteresis
0.3
V
IIH
Input High Current
VIN = VDD
−10
µA (min)
IIL
Input Low Current
VIN = 0V
10
µA (max)
CIN
Digital Input Capacitance
20
pF
DIGITAL INPUTS: P1_VIDx, P2_VIDx, GPI_9, GPI_8, GPIO_7, GPIO_6, GPIO_5, GPIO_4 (When respective bit set in
Register BEh GPI/VID Level Control)
VIH
Alternate Input High Voltage (AGTL+ Compatible)
0.8
V (min)
VIL
Alternate Input Low Voltage (AGTL+ Compatible)
0.4
V (max)
19
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LM94
DC Electrical Characteristics
LM94
AC Electrical Characteristics
The following limits apply for +3.0 VDC to +3.6 VDC, unless otherwise noted. Bold face limits apply for TA = TJ = TMIN to
TMAX of the operating range; all other limits TA = TJ = 25˚C unless otherwise noted.
Symbol
Parameter
Conditions
Typical
(Note 9)
Limits
(Note 10)
Units
(Limits)
FAN RPM-TO-DIGITAL CHARACTERISTICS
Counter Resolution
14
bits
Number of fan tach pulses count is
based on
2
pulses
Counter Frequency
22.5
Accuracy
kHz
±6
% (max)
±6
±6
% (max)
250
330
ms (min)
ms (max)
PWM OUTPUT CHARACTERISTICS
Frequency Tolerances
±2
Duty-Cycle Tolerance
% (max)
RESET INPUT/OUTPUT CHARACTERISTICS
Output Pulse Width
Upon Power Up
Minimum Input Pulse Width
Reset Output Fall Time
1.6V to 0.4V Logic Levels
10
µs (min)
1
µs (max)
10
100
kHz (min)
kHz (max)
SMBus TIMING CHARACTERISTICS
fSMBCLK
SMBCLK (Clock) Clock Frequency
tBUF
SMBus Free Time between Stop and
Start Conditions
4.7
µs (min)
tHD;STA
Hold time after (Repeated) Start
Condition. After this period, the first
clock is generated.
4.0
µs (min)
tSU;STA
Repeated Start Condition Setup Time
4.7
µs (min)
tSU;STO
Stop Condition Setup Time
4.0
µs (min)
tSU;DAT
Data Input Setup Time to SMBCLK
High
250
ns (min)
tHD;DAT
Data Output Hold Time after SMBCLK
Low
300
1075
ns (min)
ns (max)
tLOW
SMBCLK Low Period
4.7
50
µs (min)
µs (max)
tHIGH
SMBCLK High Period
4.0
50
µs (min)
µs (max)
tR
Rise Time
1
µs (max)
tF
Fall Time
300
ns (max)
tTIMEOUT
Timeout
SMBDAT or SMBCLK low
time required to
reset the Serial Bus
Interface to the Idle State
25
35
ms
ms (min)
ms (max)
500
ms (max)
400
pF (max)
tPOR
Time in which a device must be
operational after power-on reset
CL
Capacitance Load on SMBCLK and
SMBDAT
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31
VDD > +2.8V
20
LM94
16.0 Timing Waveform
20112403
17.0 Electrical Notes
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
Note 2: All voltages are measured with respect to GND, unless otherwise noted.
Note 3: When the input voltage (VIN) at any pin exceeds the power supplies (VIN < (GND or AGND) or VIN > VDD, except for analog voltage inputs), the current
at that pin should be limited to 10 mA. The 100 mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with
an input current of 10 mA to ten. Parasitic components and/or ESD protection circuitry are shown below for the LM94’s pins. Care should be taken not to forward
bias the parasitic diode, D1, present on pins D+ and D− as shown in circuits C and D. Doing so by more than 50 mV may corrupt temperature measurements. D1
and the ESD Clamp are connected between V+ (VDD, AD_IN16) and GND as shown in circuit B. SNP stands for snap-back device.
Pin #
Circuit
GPIO_0/TACH1
Symbol
1
A
GPIO_1/TACH2
2
A
GPIO_2/TACH3
3
A
GPIO_3/TACH4
4
A
GPIO_4 / P1_THERMTRIP
5
A
GPIO_5 / P2_THERMTRIP
6
A
GPIO_6
7
A
GPIO_7
8
A
VRD1_HOT
9
A
VRD2_HOT
10
A
SCSI_TERM1
11
A
SCSI_TERM2
12
A
SMBDAT
13
A
SMBCLK
14
A
ALERT/XtestOut
15
A
RESET
16
A
AGND
17
B (Internally
shorted to
GND pin.)
VREF
18
A
REMOTE1–
19
C
REMOTE1+
20
D
REMOTE2–
21
C
REMOTE+
22
D
21
All Input Circuits
Circuit A
Circuit B
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LM94
17.0 Electrical Notes
Symbol
(Continued)
Pin #
Circuit
AD_IN1
23
D
AD_IN2
24
D
AD_IN3
25
D
AD_IN4
26
E
AD_IN5
27
E
AD_IN6
28
E
AD_IN7
29
E
AD_IN8
30
E
AD_IN9
31
E
AD_IN10
32
E
AD_IN11
33
E
AD_IN12
34
E
AD_IN13
35
E
AD_IN14
36
E
AD_IN15
37
D
ADDR_SEL
38
A
AD_IN16/VDD (V+)
39
B
GND
40
B (Internally
shorted to
AGND.)
PWM1
41
A
PWM2
42
A
P1_VID0
43
A
P1_VID1
44
A
P1_VID2
45
A
P1_VID3
46
A
P1_VID4
47
A
P1_VID5
48
A
P1_PROCHOT
49
A
P2_PROCHOT
50
A
P2_VID0
51
A
P2_VID1
52
A
P2_VID2
53
A
P2_VID3
54
A
P2_VID4
55
A
P2_VID5
56
A
All Input Circuits
Circuit C
Circuit D
Circuit E
Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin. Charged device model (CDM)
simulates a pin slowly acquiring charge (such as from a device sliding down the feeder in an automated assembler) then rapidly being discharged.
Note 5: Reflow temperature profiles are different for lead-free and non lead-free packages.
Note 6: The maximum power dissipation must be de-rated at elevated temperatures and is dictated by TJMAX, θJA and the ambient temperature, TA. The maximum
allowable power dissipation at any temperature is PD MAX= (TJMAX − TA) / θJA. The θJAfor the LM94 when mounted to 1 oz. copper foil PCB the θJA with different
air flow is listed in the following table.
Air Flow
Junction to Ambient Thermal Resistance, θJA
0 m/s
79 ˚C/W
1.14 m/s (225 LFPM)
62 ˚C/W
2.54 m/s (500 LFPM)
52 ˚C/W
Note 7: See the URL "http://www.national.com/packaging/" for other recommendations and methods of soldering surface mount devices.
Note 8: At the time of first pubication of this specification (Jan 2006), this specification applies to either Pentium or Xeon Processors on 90nm or 65nm process when
TruTherm is selected. When TruTherm is deselected this specification applies to an MMBT3904. This specification does include the error caused by the variability
of the diode ideality and series resistance parameters.
Note 9: Typical parameters are at TJ = TA = 25 ˚C and represent most likely parametric norm.
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22
LM94
17.0 Electrical Notes
(Continued)
Note 10: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 11: TUE (Total Unadjusted Error) includes Offset, Gain and Linearity errors of the ADC.
Note 12: Total Monitoring Cycle Time includes all temperature and voltage conversions.
Note 13: Leakage current approximately doubles every 20 ˚C.
Note 14: A total digital I/O current of 40 mA can cause 6 mV of offset in Vref.
Note 15: Timing specifications are tested at the TTL logic levels, VIL = 0.4V for a falling edge and VIH = 2.4V for a rising edge. TRI-STATE output voltage is forced
to 1.4V.
23
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LM94 TruTherm™ Hardware Monitor with PI Loop Fan Control for Server Management
18.0 Physical Dimensions
inches (millimeters) unless otherwise noted
56-Lead Molded TSSOP Package,
JEDEC Registration Number MO-153 Variation EE,
Order Number LM94CIMT or LM94CIMTX,
NS Package Number MTD56
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.
For the most current product information visit us at www.national.com.
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WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and whose failure to perform when
properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to result
in a significant injury to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be reasonably
expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
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