STTS424E02BDA3E STMICROELECTRONICS [STMicroelectronics], STTS424E02BDA3E Datasheet - Page 6

• Manufacturer Part Number: STTS424E02BDA3E
• Description: Memory module temperature sensor with a 2 Kb SPD EEPROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Description
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Description
The STTS424E02 is targeted for DIMM Modules in Mobile Personal Computing Platforms
(Laptops), Server Memory Modules and other industrial applications. The Thermal Sensor
(TS) in the STTS424E02 is compliant with the JEDEC specification, which defines Memory
Module Thermal Sensors requirements for Mobile platforms. The 2 Kbit Serial Presence
Detect (SPD) I
the STTS424E02 is organized as 256 x8 bits and is functionally identical to the industry
standard M34E02.
The TS-SPD EEPROM combination provides space as well as cost savings for Mobile and
Server Platform Dual Inline Memory Modules (DIMM) manufacturers, as it is packaged in
the compact 2 mm x 3 mm 8-lead DFN package which is available in two variations. The DA
package has a maximum height of 0.90 mm. The DN package has an identical footprint as
the DA package with a thinner maximum height of 0.80 mm. The DN package is compliant
to JEDEC MO-229, variation WCED-3.
The temperature sensor includes a band gap-based temperature sensor and 10-bit Analog-
to-Digital Converter (ADC) which monitor and digitize the temperature to a resolution of up
to 0.25°C. The typical accuracies over these temperature ranges are:
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The temperature sensor in the STTS424E02 is specified for operating at supply voltages
from 2.7 V to 3.6 V. Operating at 3.3 V, the supply current is 100 µA (typ).
The on-board sigma delta ADC converts the measured temperature to a digital value that is
calibrated in °C. For Fahrenheit applications, a lookup table or conversion routine is
required. The STTS424E02 is factory-calibrated and requires no external components to
measure temperature.
The digital temperature sensor component has user-programmable registers that provide
the capabilities for DIMM temperature-sensing applications. The open drain Event output pin
is active when the monitoring temperature exceeds a programmable limit, or it falls above or
below an alarm window. The user has the option to set the Event output as a critical
temperature output. This pin can be configured to operate in either a comparator mode for
thermostat operation or in interrupt mode.
The 2 Kbit serial EEPROM memory in the STTS424E02 has the ability to permanently lock
the data in its first half (upper) 128 bytes (locations 00h to 7Fh). This facility has been
designed specifically for use in DRAM DIMMs with SPD. All of the information concerning
the DRAM module configuration (e.g. access speed, size, and organization) can be kept
write protected in the first half of the memory. The second half (lower) 128 bytes of the
memory can be write protected using two different software write protection mechanisms.
By sending the device a specific sequence, the first 128 bytes of the memory become write
protected: permanently or resettable. In the STTS424E02 the EEPROM Write Control (WC)
is always held low. Thus, the write protection of the memory array is dependent on whether
the software protection has been set.
±3°C (max) over the full temperature measurement range of –40°C to 125°C,
±2°C in the +40°C to +125°C temperature range, and
±1°C in the +75°C to +95°C temperature range.
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C-compatible Electrically Erasable Programmable Memory (EEPROM) in
STTS424E02