Document
SE95
Ultra high accuracy digital temperature sensor and thermal watchdog
Rev. 07 — 2 September 2009
Product data sheet
1. General description
The SE95 is a temperature-to-digital converter using an on-chip band gap temperature sensor and Sigma Delta analog-to-digital conversion technique. The device is also a thermal detector providing an overtemperature detection output.
The SE95 contains a number of data registers accessed by a controller via the 2-wire serial I2C-bus interface:
• Configuration register (Conf) to store the device settings such as sampling rate,
device operation mode, OS operation mode, OS polarity, and OS fault queue
• Temperature register (Temp) to store the digital Temp reading • Set-point registers (Tos and Thyst) to store programmable overtemperature shutdown
and hysteresis limits
• Identification register (ID) to store manufacturer numbers
The device includes an open-drain output (pin OS) which becomes active when the temperature exceeds the programmed limits. There are three selectable logic address pins (pins A2 to A0) so that eight devices can be connected on the same bus without address conflict.
The SE95 can be configured for different operation conditions. It can be set in normal mode to periodically monitor the ambient temperature, or in shutdown mode to minimize power consumption. The OS output operates in either of two selectable modes: OS comparator mode and OS interrupt mode. Its active state can be selected as either HIGH or LOW. The fault queue that defines the number of consecutive faults in order to activate the OS output is programmable as well as the set-point limits.
The temperature register always stores a 13-bit two’s complement data giving a temperature resolution of 0.03125 °C. This high temperature resolution is particularly useful in applications of measuring precisely the thermal drift or runaway. For normal operation and compatibility with the LM75A, only the 11 MSBs are read, with a resolution of 0.125 °C to provide the accuracies specified. To be compatible with the LM75, read only the 9 MSBs.
The device is powered-up in normal operation mode with the OS in comparator mode, temperature threshold of 80 °C and hysteresis of 75 °C, so that it can be used as a stand-alone thermostat with those pre-defined temperature set points. The conversion rate is programmable, with a default of 10 conversions/s.
NXP Semiconductors
SE95
Ultra high accuracy digital temperature sensor and thermal watchdog
2. Features
I Pin-for-pin replacement for industry standard LM75/LM75A I Specification of a single part over supply voltage from 2.8 V to 5.5 V I Small 8-pin package types: SO8 and TSSOP8 (MSOP8) I I2C-bus interface to 400 kHz with up to 8 devices on the same bus I Supply voltage from 2.8 V to 5.5 V I Temperature range from −55 °C to +125 °C I 13-bit ADC that offers a temperature resolution of 0.03125 °C I Temperature accuracy of ± 1 °C from −25 °C to +100 °C I Programmable temperature threshold and hysteresis set points I Supply current of 7.0 µA in shutdown mode for power conservation I Stand-alone operation as thermostat at power-up I ESD protection exceeds 1000 V for Human Body Model (HBM) per JESD22-A114 and
150 V for Machine Model (MM) per JESD22-A115 I Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
3. Applications
I System thermal management I Personal computers I Electronics equipment I Industrial controllers
4. Ordering information
Table 1. Type number SE95D SE95DP
SE95U
Ordering information Package Temperature range Name −55 °C to +125 °C SO8 −55 °C to +125 °C TSSOP8
−55 °C to +125 °C -
Description plastic small outline package; 8 leads; body width 3.9 mm plastic thin shrink small outline package; 8 leads; body width 3 mm wafer
Version SOT96-1 SOT505-1
-
SE95_7
Product data sheet
Rev. 07 — 2 September 2009
© NXP B.V. 2009. All rights reserved.
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NXP Semiconductors
5. Block diagram
SE95
Ultra high accuracy digital temperature sensor and thermal watchdog
SE95
BIAS BAND GAP OSCILLATOR
POR
ADC CONTROL AND OTP CONTROL
SIGMA DELTA MODULATOR
bit stream
DECIMATION FILTER
OTP
Conf Temp Tos Thyst
REGISTER BANK
Fig 1. Block diagram of SE95
I2C-BUS INTERFACE LOGIC
5
6
7
2
1
A2 A1 A0 SCL SDA
4 GND
6. Pinning information
6.1 Pinning
8 VCC
INTERRUPTION LOGIC
3 OS
002aae892
SDA 1 SCL 2 OS 3 GND 4
SE95D
8 VCC 7 A0 6 A1
5 A2
002aac537
Fig 2. Pin configuration for SO8
SDA 1 SCL 2 OS 3 GND 4
SE95DP
8 VCC 7 A0 6 A1 5 A2
002aac536
Fig 3. Pin configuration for TSSOP8
6.2 Pin description
Table 2. Symbol SDA SCL OS GND A2
Pin description
Pin
Description
1
I2C-bus serial bidirectional data line digital I/O; open-drain
2
I2C-bus serial clock digital input
3
overtemperature shutdown output; open-drain
4
ground; to be connected to the system ground
5
user-defined address bit 2 digital input
SE95_7
Product data sheet
Rev. 07 — 2 September 2009
.