Datasheet

ManualsBrandsNXP SEMICONDUCTORS ManualsSensorsTemperature sensor SMD

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 I

C-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.

SE95

Ultra high accuracy digital temperature sensor and thermal

watchdog

Rev. 07 — 2 September 2009 Product data sheet

Summary of content (27 pages)

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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.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 2. Features n n n n n n n n n n n n Pin-for-pin replacement for industry standard LM75/LM75A Specification of a single part over supply voltage from 2.8 V to 5.5 V Small 8-pin package types: SO8 and TSSOP8 (MSOP8) I2C-bus interface to 400 kHz with up to 8 devices on the same bus Supply voltage from 2.8 V to 5.5 V Temperature range from −55 °C to +125 °C 13-bit ADC that offers a temperature resolution of 0.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 5. Block diagram ADC CONTROL AND OTP CONTROL SE95 OTP 8 VCC Conf BIAS Temp bit stream BAND GAP SIGMA DELTA MODULATOR Tos DECIMATION FILTER INTERRUPTION LOGIC Thyst OSCILLATOR REGISTER BANK POR 3 OS I2C-BUS INTERFACE LOGIC 5 A2 Fig 1. 6 A1 7 A0 2 1 4 SCL SDA GND 002aae892 Block diagram of SE95 6. Pinning information 6.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog Table 2. Pin description …continued Symbol Pin Description A1 6 user-defined address bit 1 digital input A0 7 user-defined address bit 0 digital input VCC 8 supply voltage 7. Functional description 7.1 General operation The SE95 uses the on-chip band gap sensor to measure the device temperature with a resolution of 0.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog In OS interrupt mode, the OS output is used for thermal interruption. When the device is powered-up, the OS output is first activated only when Temp exceeds Tos; then it remains active indefinitely until being reset by a read of any register.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 7.2 OS output and polarity The OS output is an open-drain output and its state represents results of the device watchdog operation as described in Section 7.1. In order to observe this output state, an external pull-up resistor is needed. The resistor should be as large as possible, up to 200 kΩ, to minimize the Temp reading error due to internal heating by the high OS sinking current.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 7.5 Shutdown mode The device operation mode is selected by programming bit SHUTDOWN of register Conf. Setting bit SHUTDOWN to logic 1 will put the device into shutdown mode. Resetting bit SHUTDOWN to logic 0 will return the device to normal mode. In shutdown mode, the device draws a small current of approximately 7.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog false alert if the address 0Ch is sent and cannot be active on the I2C-bus if this address is used. Consider using the SE98 since it supports SMBus ARA as well as time-out features and provides ±1 °C accuracy. Table 4. Address table MSB LSB 1 0 0 1 A2 A1 A0 8.2 Register list The SE95 contains 7 data registers. The registers can be 1 byte or 2 bytes wide, and are defined in Table 5.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog At power-up, the pointer value is preset to logic 0 for register Temp; users can then read the temperature without specifying the pointer byte. 8.4 Configuration register The Configuration (Conf) register is a read/write register and contains an 8-bit non-complement data byte that is used to configure the device for different operating conditions. Table 6 shows the bit assignments of this register. Table 6.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog When reading register Temp, all 16 bits of the two data bytes (MSByte and LSByte) must be collected and then the two’s complement data value according to the desired resolution must be selected for the temperature calculation. Table 8 shows the example for 11-bit two’s complement data value, Table 9 shows the example for 13-bit two’s complement data value. Table 8.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog Obviously, for 9-bit Temp data application in replacing the industry standard LM75, just use only 9 MSB bits of the two bytes and disregard 7 LSB of the LSByte. The 9-bit Temp data with 0.5 °C resolution of the SE95 is defined exactly in the same way as for the standard LM75 and it is here similar to the Tos and Thyst registers. 8.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 8.7 Protocols for writing and reading the registers The communication between the host and the SE95 must follow the rules strictly as defined by the I2C-bus management. The protocols for SE95 register read/write operations are illustrated in Figure 5 to Figure 10 together with the following definitions: 1. Before a communication, the I2C-bus must be free or not busy.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 1 2 3 4 1 0 0 1 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 0 0 0 0 0 0 0 1 A 0 0 0 4 5 6 7 8 9 SCL SDA S A2 A1 A0 W A device address START pointer byte write P configuration data byte device acknowledge device acknowledge Fig 5.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 SCL (next) SDA S 1 0 0 1 A2 A1 A0 W A 0 0 0 device address 0 0 0 device acknowledge 3 4 (next) A device acknowledge write 2 P0 pointer byte START 1 P1 5 6 7 8 9 1 2 3 4 5 6 7 8 9 SCL (cont.) SDA (cont.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 9. Limiting values Table 15. Limiting values In accordance with the Absolute Maximum Rating System (IEC 60134). Symbol Parameter VCC Conditions Min Max Unit supply voltage −0.3 +6.0 V VI(SCL) input voltage on pin SCL −0.3 +6.0 V VI(SDA) input voltage on pin SDA −0.3 +6.0 V VI(A0) input voltage on pin A0 −3.0 VCC + 0.3 V VI(A1) input voltage on pin A1 −3.0 VCC + 0.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 11. Static characteristics Table 17. Static characteristics VCC = 2.8 V to 5.5 V, Tamb = −55 °C to +125 °C; unless otherwise specified. Symbol Parameter Tacc temperature accuracy Min Typ[1] Max Unit Tamb = −25 °C to +100 °C −1.0 - +1.0 °C Tamb = −55 °C to +125 °C −2.0 - +2.0 °C Tamb = −25 °C to +100 °C −2 - +2 °C Tamb = −55 °C to +125 °C Conditions [2] VCC = 2.8 V to 3.6 V [2] VCC = 3.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 12. Dynamic characteristics Table 18. Dynamic characteristics[1] VCC = 2.8 V to 5.5 V, Tamb = −55 °C to +125 °C; unless otherwise specified. Symbol Parameter TCLK SCL clock period Conditions Min Typ Max Unit see Figure 11 2.5 - - µs t(SCL)H HIGH period of the SCL clock 0.6 - - µs t(SCL)L LOW period of the SCL clock 1.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 13. Performance curves 25 ICC(SD) (µA) 20 001aad617 001aad618 300 VCC = 5.5 V ICC (µA) VCC = 5.5 V 3.9 V 3.3 V 2.8 V 200 15 3.9 V 10 3.3 V 2.8 V 100 5 0 −50 −25 0 25 50 75 Fig 12. Shutdown supply current as a function of temperature 001aad619 300 30 conversions/s ICC (µA) 200 0 −50 100 125 T (°C) 10 conversions/s −25 0 25 50 75 100 125 T (°C) Fig 13.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 14. Application information The SE95 is sensitive to power supplies with ramp-up time ≤2 ms and could NACK or hang the I2C-bus. In most applications the SE95 will function properly since power supplies have a >2 ms ramp-up time. If the power supply ramp-up time is ≤2 ms, use an RC network with R = 300 Ω and C = 10 µF, as shown in Figure 18, to add about 3 ms to the ramp-up time.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 15. Package outline SO8: plastic small outline package; 8 leads; body width 3.9 mm SOT96-1 D E A X c y HE v M A Z 5 8 Q A2 A (A 3) A1 pin 1 index θ Lp 1 L 4 e detail X w M bp 0 2.5 5 mm scale DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT A max. A1 A2 A3 bp c D (1) E (2) e HE L Lp Q v w y Z (1) mm 1.75 0.25 0.10 1.45 1.25 0.25 0.49 0.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm D E SOT505-1 A X c y HE v M A Z 5 8 A2 pin 1 index (A3) A1 A θ Lp L 1 4 detail X e w M bp 0 2.5 5 mm scale DIMENSIONS (mm are the original dimensions) UNIT A max. A1 A2 A3 bp c D(1) E(2) e HE L Lp v w y Z(1) θ mm 1.1 0.15 0.05 0.95 0.80 0.25 0.45 0.25 0.28 0.15 3.1 2.9 3.1 2.9 0.65 5.1 4.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 16. Soldering of SMD packages This text provides a very brief insight into a complex technology. A more in-depth account of soldering ICs can be found in Application Note AN10365 “Surface mount reflow soldering description”. 16.1 Introduction to soldering Soldering is one of the most common methods through which packages are attached to Printed Circuit Boards (PCBs), to form electrical circuits.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 16.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog maximum peak temperature = MSL limit, damage level temperature minimum peak temperature = minimum soldering temperature peak temperature time 001aac844 MSL: Moisture Sensitivity Level Fig 21. Temperature profiles for large and small components For further information on temperature profiles, refer to Application Note AN10365 “Surface mount reflow soldering description”. 17. Abbreviations Table 21.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 18. Revision history Table 22.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 19. Legal information 19.1 Data sheet status Document status[1][2] Product status[3] Definition Objective [short] data sheet Development This document contains data from the objective specification for product development. Preliminary [short] data sheet Qualification This document contains data from the preliminary specification.
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SE95 NXP Semiconductors Ultra high accuracy digital temperature sensor and thermal watchdog 21. Contents 1 2 3 4 5 6 6.1 6.2 7 7.1 7.2 7.3 7.4 7.5 7.6 8 8.1 8.2 8.3 8.4 8.5 8.6 8.7 9 10 11 12 13 14 15 16 16.1 16.2 16.3 16.4 17 18 19 19.1 19.2 19.3 19.4 General description . . . . . . . . . . . . . . . . . . . . . . 1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Ordering information . . . . . . . . . . . .