LM96194CISQ/NOPB National Semiconductor, LM96194CISQ/NOPB Datasheet - Page 10

• Manufacturer Part Number: LM96194CISQ/NOPB
• Description: IC TRUTHERM HDWR MONITOR 48-LLP
• Manufacturer: National Semiconductor
• Series: PowerWise®, TruTherm®r

Specifications of LM96194CISQ/NOPB

• Function: Fan Control, Temp Monitor
• Topology: ADC (Sigma Delta), Comparator, Fan Control, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 85°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-LLP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM96194CISQTR

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12.0 Functional Description
The LM96194 provides 9 channels of voltage monitoring, 4
remote thermal diode monitors, an internal/local ambient tem-
perature sensor, a PROCHOT monitor, 4 fan tachometers, 8
GPIOs, THERMTRIP monitor for masking error events, 1 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 LM96194 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 con-
dition when activated by a fan tach error.
The
TruTherm technology for precision “Remote Diode” readings
of processors on 90nm process geometry or smaller. Read-
ings from the external thermal diodes and the internal tem-
perature 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's-
complement digital value with the LSb representing 0.0625°
C.
All of the analog inputs include internal scaling resistors, ex-
ept for AD_IN1, AD_IN2, AD_IN3 and AD_IN8. External scal-
ing resistors are required for measuring ±12V. The inputs are
converted to 8-bit digital values such that a nominal voltage
appears at ¾ scale for positive voltages and ¼ scale for neg-
ative voltages. The analog inputs are intended to be connect-
ed to both baseboard resident VRDs and to standard voltage
rails supplied by a SSI compliant power supply.
The LM96194 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
LM96194. When VRD10 mode is selected GPI8 and GPI9
can be used to detect external error flags whose state is re-
flected in the status registers.
Error events are captured in two sets of mirrored status reg-
isters (BMC Error Status Registers and Host Status Regis-
ters) allowing two controllers access to the status information
without any interference.
The LM96194's ALERT output supports interrupt mode or
comparator mode of operation. The comparator mode is only
functional for thermal monitoring.
The LM96194 provides a number of internal registers, which
are detailed in the register section of this document.
12.1 MONITORING CYCLE TIME
When the LM96194 is powered up, it cycles through each
temperature measurement followed by the analog voltages in
sequence, and it continuously loops through the sequence.
The total monitoring cycle time is not less than 100 ms, as this
is the time period that most external micro-controllers require
to read the register values.
Each measured value is compared to values stored in the limit
registers. When the measured value violates the pro-
grammed limit, a corresponding status bit in the B_Error and
H_Error Status Registers is set.
LM96194
incorporates
National
Semiconductor's
10
The PROCHOT, tachometer and dynamic VID/Vccp monitor-
ing is performed independently of the analog and temperature
monitoring cycle.
12.2 ΣΔ A/D INHERENT AVERAGING
The ΣΔ A/D architecture filters the input signal. During one
conversion many samples are taken of the input voltage and
these samples are effectively averaged to give the final result.
The output of the ΣΔ A/D is the average value of the signal
during the sampling interval. For a voltage measurement, the
samples are accumulated for 1.5 ms. For a temperature mea-
surement, the samples are accumulated for 8.4 ms.
12.3 TEMPERATURE MONITORING
The LM96194 remote diode target is the embedded thermal
diode found in a Xeon class processor in 90nm processes but
can also work with any Intel Corporation ™ based processor
in 90nm or 65nm. The LM96194 has an advanced thermal
diode input stage using National's TruTherm technology that
reduces the spread in ideality found in sub-micron geometry
thermal diodes. Internal analog filtering has been included in
the thermal diode input stage thus minimizing the need for
external thermal diode filter capacitors. In addition a digital
filter has been included for the thermal diode temperature
readings.
In some cases instead of using the embedded thermal diode,
found on the Xeon processor, a diode connected 2N3904
transistor type can also be used. An example of this would be
a MMBT3904 with its collector and base tied to the thermal
diode REMOTE+ pin and the emitter tied to the thermal diode
REMOTE− pin. Since the MMBT3904 is a surface mount de-
vice and has very small thermal mass, it measures the board
temperature where it is mounted. The ideality and series re-
sistance varies for different diodes. Therefore the LM96194
has register support to allow calibration selection between a
2N3904 or a Xeon processor. The LM96194 is optimized for
typical Intel processors on 90nm or 65nm process or 2N3904
transistor. Other transistor types may be used but may have
additional error that can be corrected for by programming the
appropriate Zone Adjustment Offset register.
The LM96194 acquires temperature data from four different
sources:
All of these values, although not necessarily simultaneously,
can be used to control fans, compared against limits, etc.
The temperature value registers are located at addresses
06h-09h, 50h–55h and 10h-23h. The temperature sources
are referred to as “zones” for convenience:
4 external diodes (embedded in a processor or discrete)
1 internal diode (internal to the LM96194)
1 analog temperature sensors, such as the LM60, that are
connected to the AD_15 pin
a temperature value can be externally written into an
LM96194 register from the SMBus.