AD7415_15 AD | Alldatasheet

Document overview

  • Manufacturer or author: Provided By alldatasheet.com(free datasheet download site)
  • PDF pages: 20

Technical content

±0.5°C Accurate, 10-Bit Digital Temperature Sensors in SOT-23 AD7414/AD7415 Rev. F Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent ri ghts of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2001–2010 Analog Devices, Inc. All rights reserved.

FEATURES

10-bit temperature-to-digital converter Temperature range: −40°C to +125°C Typical accuracy of ±0.5°C at +40°C SMBus/I 2C®-compatible serial interface 3 μA power-down current Temperature conversion time: 29 μs typ Space-saving 6-lead (AD7414) and 5-lead (AD7415) SOT-23 packages Pin selectable addressing via AS Overtemperature indicator (AD7414 Only) SMBus alert function (AD7414 only) 4 versions allow 8 I 2C addresses (AD7414) 2 versions allow 6 I2C addresses (AD7415)

APPLICATIONS

The AD7414/AD7415 are complete temperature monitoring systems in 6-lead and 5-lead SOT-23 packages. They contain a band gap temperature sensor and a 10-bit ADC to monitor and digitize the temperature reading to a resolution of 0.25°C. The AD7414/AD7415 provide a 2-wire serial interface that is compatible with SMBus and I 2C interfaces. The parts come in four versions: the AD7414/AD7415-0, AD7414/AD7415-1, AD7414-2, and AD7414-3. The AD7414/AD7415-0 and AD7414/AD7415-1 versions provide a choice of three different SMBus addresses for each version. All four AD7414 versions give the possibility of eight different I 2C addresses while the two AD7415 versions allow up to six I2C addresses to be used. The AD7414/AD7415’s 2.7 V supply voltage, low supply current, serial interface, and small package size make them ideal for a variety of applications, including personal computers, office equipment, cellular phones, and domestic appliances. In the AD7414, on-chip registers can be programmed with high and low temperature limits, and an open-drain overtemperature indicator output (ALERT) becomes active when a programmed FUNCTIONAL BLOCK DIAGRAM SDA SCL VDD SMBus/I2C INTERFACE 10-BIT ANALOG-DIGITAL CONVERTER BAND GAP TEMPERATURE SENSOR CONFIGURATION REGISTER TEMPERATURE VALUE REGISTER AD7415 AS GND AS GND SDA SCL TLOW SETPOINT REGISTER SETPOINT COMPARATOR ALERT VDD AD7414 SMBus/I2C INTERFACE 10-BIT ANALOG-DIGITAL CONVERTER BAND GAP TEMPERATURE SENSOR CONFIGURATION REGISTER TEMPERATURE VALUE REGISTERTHIGH SETPOINT REGISTER 02463-001 Figure 1. limit is exceeded. A configuration register allows programming of the state of the ALERT output (active high or active low). This output can be used as an interrupt or as an SMBus alert. PRODUCT HIGHLIGHTS 1. On-chip temperature sensor. The sensor allows an accurate measurement of the ambient temperature to be made. It is capable of ±0.5°C temperature accuracy. 2. SMBus/I 2C-compatible serial interface. The interface offers pin selectable choice of three addresses per version of the AD7414/AD7415, eight address options in total for the AD7414, and six in total for the AD7415. 3. Supply voltage of 2.7 V to 5.5 V . 4. Space-saving 5-lead and 6-lead SOT-23 packages. 5. 10-bit temperature reading to 0.25°C resolution. 6. Overtemperature indicator. This indicator can be software disabled. It is used as an interrupt of SMBus alert. 7. One-shot and automatic temperature conversion rates.

Rev. F | Page 2 of 20 TABLE OF CONTENTS

REVISION HISTORY

11/10—Rev. E to Rev. F 4/05—Rev. D to Rev. E 9/04—Rev. C to Rev. D. 8/03—Rev. B to Rev. C. 11/02—Rev. A to Rev. B. 10/02—Rev. 0 to Rev. A. Added to Typical Temperature 7/01—Revision 0: Initial Version

Rev. F | Page 3 of 20 SPECIFICATIONS TA = TMIN to TMAX, VDD = 2.7 V to 5.5 V , unless otherwise noted. Temperature range as follows: A version = −40°C to +125°C. Table 1. Parameter A Version Unit Test Conditions/Comments TEMPERATURE SENSOR AND ADC Accuracy1 ±0.5 °C typ VDD = 3 V @ +40°C −0.87 to +0.822 °C max VDD = 3 V @ +40°C ±1.5 °C max VDD = 3 V @ −40°C to +70°C ±2.0 °C max VDD = 3 V @ −40°C to +85°C ±3.0 °C max VDD = 3 V @ −40°C to +125°C ±2.0 °C typ VDD = 3 V @ −40°C to +125°C ±1.87 2 °C max VDD = 5.5 V @ +40°C ±2.0 °C typ VDD = 5.5 V @ −40°C to +85°C ±3.0 °C max VDD = 5.5 V @ −40°C to +85°C ±3.0 °C typ VDD = 5.5 V @ −40°C to +125°C Resolution 10 Bits Update Rate, tR 800 ms typ Temperature Conversion Time 25 μs typ POWER SUPPLIES Supply Current3 Peak Supply Current4 1.2 mA typ Current during conversion Supply Current – Nonconverting 900 μA max Peak current between conversions Inactive Serial Bus5 Normal Mode @ 3 V 169 μA typ Supply current with serial bus inactive. Part not converting and D7 of configuration register = 0. Normal Mode @ 5 V 188 μA typ Active Serial Bus6 Normal Mode @ 3 V 180 μA typ Supply current with serial bus active. Part not converting and D7 of configuration register = 0. D7 of configuration register = 1. Typical values are 0.04 μA at 3 V and 0.5 μA at 5 V. Normal Mode @ 5 V 214 μA typ Shutdown Mode 3 μA max DIGITAL INPUT Input High Voltage, VIH 2.4 V min Input Low Voltage, VIL 0.8 V max Input Current, IIN7 ±1 μA max VIN = 0 V to VDD Input Capacitance, CIN 10 pF max All digital inputs DIGITAL OUTPUT (OPEN-DRAIN) Output High Voltage, VOH 2.4 V min Output Low Voltage, VOL 0.4 V max IOL = 1.6 mA Output High Current, IOH 1 μA max VOH = 5 V Output Capacitance, COUT 10 pF max Typ = 3 pF ALERT Output Saturation Voltage 0.8 V max IOUT = 4 mA

2 100% production tested at 40°C to these limits. conversion rate of 1.25 kHz is 940 μW. 4 This peak supply current is required for 29 μs (the conversion time plus power-up time) out of every 800 μs (the conversion rate). 5 These current values are derived by not issuing a stop condition at the end of a write or read, thus preventing the part from going into a conversion. 6 The current is derived assuming a 400 kHz serial clock being active continuously. 7 On power-up, the initial input current, IIN, on the AS pin is typically 50 μA. rate but has a negative effect on the EMC behavior of the part. 9 Guaranteed by design. Not tested in production. Figure 2. Diagram for Serial Bus Timing

Rev. F | Page 5 of 20 ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Rating VDD to GND −0.3 V to +7 V SDA Input Voltage to GND −0.3 V to +7 V SDA Output Voltage to GND −0.3 V to +7 V SCL Input Voltage to GND −0.3 V to +7 V ALERT Output Voltage to GND −0.3 V to +7 V Operating Temperature Range −40°C to +125°C Storage Temperature Range −65°C to +150°C Junction Temperature 150°C 5-Lead SOT-23 (RJ-5) Power Dissipation1, 2 WMAX = (TJMAX − TA)/θJA Thermal Impedance3 θJA, Junction-to-Ambient (still air) 240°C/W 6-Lead SOT-23 (RJ-6) Power Dissipation1, 2 W MAX = (TJMAX − TA)/θJA Thermal Impedance3 θJA, Junction-to-Ambient (still air) 190.4°C/W 8-Lead MSOP (RM-8) Power Dissipation1, 2 W MAX = (TJMAX − TA)/θJA Thermal Impedance3 θJA, Junction-to-Ambient (still air) 205.9°C/W θJC, Junction-to-Case 43.74°C/W IR Reflow Soldering Peak Temperature 220°C (0°C/5°C) Time at Peak Temperature 10 sec to 20 sec Ramp-up Rate 3°C/s max Ramp-down Rate −6°C/s max Ramp from 25°C to Peak Temperature 6 minutes max IR Reflow Soldering in Pb-Free Package Peak Temperature 260°C (0°C) Time at Peak Temperature 20 sec to 40 sec Ramp Rate 3°C/s max Ramp-Down Rate −6°C/s max Ramp from 25°C to Peak Temperature 8 minutes max 1 Values relate to package being used on a standard 2-layer PCB. 2 TA = ambient temperature.

3 Junction-to-case resistance is applicable to components featuring a

preferential flow direction, such as components mounted on a heat sink. Junction-to-ambient resistance is more useful for air-cooled, PCB-mounted components. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ESD CAUTION

measurement of the ambient device temperature to be made. measurement range of −40°C to +125°C.

  • Switching between normal operation and full power- down
  • Enabling or disabling the SCL and SDA filters
  • Enabling or disabling the ALERT function
  • Setting the ALERT pin polarity SUPPLY 2.7V TO 5.5V 10μF 1kΩ0.1μF SDA SCL ALERT AS GND AD7414 VDD 02463-006 10kΩ 10kΩ 10kΩ VDD VDD VDD μC/μP

Figure 6. Typical Connection Diagram voltage of a transistor, operated at constant current. q is the charge on the electron (1.6 × 10–19 Coulombs). T is the absolute temperature in Kelvins. N is the ratio of the two currents.

them during normal operation. Table 12. AD7415 Configuration Register Settings D6 Bypass SDA and SCL filtering if = 0. D2 Initiate a one-shot temperature conversion if set to 1. The bit status is not stored; thus this bit is 0 if read. and power down again. This is a very power efficient mode. limit after the read operation, the flag is set again. range of the device, −40°C to +125°C for the A grade. Table 13. Temperature Value Register (First Read) Table 14. AD7414 Temperature Value Register (Second Read) Table 15. AD7415 Temperature Value Register (Second Read) that stores the upper limit that activates the ALERT output. Table 16. THIGH Register that stores the lower limit that deactivates the ALERT output. Because it is an 8-bit register, the temperature resolution is 1°C. Table 17. TLOW Register

Figure 10. Writing to the Address Pointer Register to Select a Register for a Subsequent Read Operation

  • ••
  • ••
  • ••
  • •• 02463-011 R/W

Figure 11. Writing to the Address Pointer Register Followed by a Single Byte of Data to the Selected Register

0 R/W

Figure 12. Reading a Single Byte of Data from a Selected Register

  • ••
  • ••
  • ••
  • •• 1 9 0 0 1 9 02463-013 R/W

Figure 13. Reading Two Bytes of Data from the Temperature Value Register

Rev. F | Page 12 of 20 SERIAL INTERFACE Control of the AD7414/AD7415 is carried out via the I2C- compatible serial bus. The AD7414/AD7415 are connected to this bus as slave device, under the control of a master device, such as the processor. SERIAL BUS ADDRESS Like all I2C-compatible devices, the AD7414/AD7415 have a 7-bit serial address. The four MSBs of this address for the AD7414/AD7415 are set to 1001. The AD7414/AD7415 are available in four versions: AD7414/AD7415-0, AD7414/ AD7415-1, AD7414-2, and AD7414-3. The first two versions have three different I 2C addresses available, which are selected by either tying the AS pin to GND, to VDD, or letting the pin float (see Table 4). By giving different addresses for the four versions, up to eight AD7414s or six AD7415s can be connected to a single serial bus, or the addresses can be set to avoid conflicts with other devices on the bus. The serial bus protocol operates as follows. The master initiates data transfer by establishing a START condition, defined as a high-to-low transition on the serial data line SDA, while the serial clock line SCL remains high. This indicates that an address/data stream follows. All slave periph- erals connected to the serial bus respond to the START condi- tion and shift in the next eight bits, consisting of a 7-bit address (MSB first) plus an R/W bit, which determines the direction of the data transfer and whether data is written to or read from the slave device. The peripheral whose address corresponds to the transmitted address responds by pulling the data line low during the low period before the ninth clock pulse, known as the acknowledge bit. All other devices on the bus remain idle while the selected device waits for data to be read from or written to it. If the R/W bit is 0, the master writes to the slave device. If the R/W bit is 1, the master reads from the slave device. Data is sent over the serial bus in sequences of nine clock pulses, eight bits of data followed by an acknowledge bit from the receiver of data. Transitions on the data line must occur during the low period of the clock signal and remain stable during the high period, because a low-to-high transition when the clock is high may be interpreted as a STOP signal. When all data bytes have been read or written, stop conditions are established. In WRITE mode, the master pulls the data line high during the 10th clock pulse to assert a STOP condition. In READ mode, the master device pulls the data line high during the low period before the ninth clock pulse. This is known as No Acknowledge. The master then takes the data line low during the low period before the 10th clock pulse, then high during the 10th clock pulse to assert a STOP condition. Any number of bytes of data may be transferred over the serial bus in one operation, but it is not possible to mix read and write in one operation. The type of operation is determined at the beginning and cannot then be changed without starting a new operation. WRITE MODE Depending on the register being written to, there are two different writes for the AD7414/AD7415. Writing to the Address Pointer Register for a Subsequent Read In order to read data from a particular register, the address pointer register must contain the address of that register. If it does not, the correct address must be written to the address pointer register by performing a single-byte write operation, as shown in Figure 10. The write operation consists of the serial bus address followed by the address pointer byte. No data is written to any of the data registers. A read operation is then performed to read the register. Writing a Single Byte of Data to the Configuration Register,THIGH Register, or TLOW Register All three registers are 8-bit registers, so only one byte of data can be written to each register. Writing a single byte of data to one of these registers consists of the serial bus address, the data register address written to the address pointer register, followed by the data byte written to the selected data register. This is illustrated in Figure 11. READ MODE Reading data from the AD7414/AD7415 is a 1- or 2-byte operation. Reading back the contents of the configuration register, the THIGH register, or the TLOW register is a single-byte read operation, as shown in Figure 12. The register address was previously set up by a single-byte write operation to the address pointer register. Once the register address has been set up, any number of reads can subsequently be performed from that register without having to write to the address pointer register again. To read from another register, the address pointer register has to be written to again to set up the relevant register address. Reading data from the temperature value register is a 2-byte operation, as shown in Figure 13. The same rules apply for a 2-byte read as a 1-byte read.

Rev. F | Page 13 of 20 SMBUS ALERT The AD7414 ALERT output is an SMBus interrupt line for devices that want to trade their ability to master for an extra pin. The AD7414 is a slave-only device and uses the SMBus ALERT to signal to the host device that it wants to talk. The SMBus ALERT on the AD7414 is used as an overtemperature indicator. The ALERT pin has an open-drain configuration that allows the ALERT outputs of several AD7414s to be wire-AND’ ed together when the ALERT pin is active low. Use D4 of the configuration register to set the active polarity of the ALERT output. The power-up default is active low. The ALERT function can be disabled or enabled by setting D5 of the configuration register to 1 or 0, respectively. The host device can process the ALERT interrupt and simultaneously access all SMBus ALERT devices through the alert response address. Only the device that pulled the ALERT low acknowledges the Alert Response Address (ARA). If more than one device pulls the ALERT pin low, the highest priority (lowest address) device wins communication rights via standard I 2C arbitration during the slave address transfer. The ALERT output becomes active when the value in the temperature value register exceeds the value in the T HIGH register. It is reset when a write operation to the configuration register sets D3 to 1 or when the temperature falls below the value stored in the T LOW register. The ALERT output requires an external pull-up resistor. This can be connected to a voltage different from VDD, provided the maximum voltage rating of the ALERT output pin is not exceeded. The value of the pull-up resistor depends on the application, but it should be as large as possible to avoid excessive sink currents at the ALERT output, which can heat the chip and affect the temperature reading. POWER-ON DEFAULTS The AD7414/AD7415 always power up with these defaults: Address pointer register pointing to the temperature value register. THIGH register loaded with 7Fh. TLOW register loaded with 80h. Configuration register loaded with 40h. Note that the AD7415 does not have any THIGH or TLOW registers. OPERATING MODES Mode 1 This is the power-on default mode of the AD7414/AD7415. In this mode, the AD7414/AD7415 does a temperature conversion every 800 ms and then partially powers down until the next conversion occurs. If a one-shot operation (setting D2 of the configuration register to a 1) is performed between automatic conversions, a conver- sion is initiated right after the write operation. After this conversion, the part returns to performing a conversion every 800 ms. Depending on where a serial port access occurs during a conversion, that conversion might be aborted. If the conversion is completed before the part recognizes a serial port access, the temperature register is updated with the new conversion. If the conversion is completed after the part recognizes a serial port access, the internal logic prevents the temperature register from being updated, because corrupt data could be read. A temperature conversion can start anytime during a serial port access (other than a one-shot operation), but the result of that conversion is loaded into the temperature register only if the serial port access is not active at the end of the conversion. Mode 2 The only other mode in which the AD7414/AD7415 operates is the full power-down mode. This mode is usually used when temperature measurements are required at a very slow rate. The power consumption of the part can be greatly reduced in this mode by writing to the part to go to a full power-down. Full power-down is initiated right after D7 of the configuration register is set to 1. When a temperature measurement is required, a write operation can be performed to power up the part and put it into one-shot mode (setting D2 of the configuration register to a 1). The power-up takes approximately 4 μs. The part then performs a conversion and is returned to full power-down. The temperature value can be read in the full power-down mode, because the serial interface is still powered up.

0.95 BSC

0.15 MAX

0.05 MIN

1.45 MAX

0.95 MIN

0.20 MAX

0.08 MIN

0.50 MAX

0.30 MIN

Figure 20. 6-Lead Small Outline Transistor Package [SOT-23]

0.65 BSC

1.10 MAX

Figure 21. 8-Lead Mini Small Outline Package [MSOP]

0.35 MIN

Figure 22. 5-Lead Small Outline Transistor Package [SOT-23]

Rev. F | Page 18 of 20 ORDERING GUIDE Model1 Temperature Range Typ Temperature Error @ 3 V Package Option Package Description Branding Ordering Quantity AD7414ARTZ-0REEL7 −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 #CHA 3,000 AD7414ARTZ-0REEL −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 #CHA 10,000 AD7414ARTZ-0500RL7 −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 #CHA 500 AD7414ARMZ-0REEL7 −40°C to +125°C ±2°C RM-8 8-Lead MSOP TOL 3,000 AD7414ARMZ-0REEL −40°C to +125°C ±2°C RM-8 8-Lead MSOP TOL 10,000 AD7414ARMZ-0 −40°C to +125°C ±2°C RM-8 8-Lead MSOP TOL 50 AD7414ARTZ-1REEL7 −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 TOH 3,000 AD7414ARTZ-1REEL −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 TOH 10,000 AD7414ARTZ-1500RL7 −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 TOH 500 AD7414ARTZ-2REEL7 −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 TOJ 3,000 AD7414ARTZ-2REEL −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 TOJ 10,000 AD7414ARTZ-3REEL7 −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 TOK 3,000 AD7414ARTZ-3REEL −40°C to +125°C ±2°C RJ-6 6-Lead SOT-23 TOK 10,000 AD7415ARTZ-0REEL7 −40°C to +125°C ±2°C RJ-5 5-Lead SOT-23 #CGA 3,000 AD7415ARTZ-0REEL −40°C to +125°C ±2°C RJ-5 5-Lead SOT-23 #CGA 10,000 AD7415ARTZ-0500RL7 −40°C to +125°C ±2°C RJ-5 5-Lead SOT-23 #CGA 500 AD7415ARTZ-1REEL7 −40°C to +125°C ±2°C RJ-5 5-Lead SOT-23 #CGB 3,000 AD7415ARTZ-1REEL −40°C to +125°C ±2°C RJ-5 5-Lead SOT-23 #CGB 10,000 AD7415ARTZ-1500RL7 −40°C to +125°C ±2°C RJ-5 5-Lead SOT-23 #CGB 500 EVAL-AD7414/15EBZ Evaluation Board 1 Z = RoHS Compliant Part.

Rev. F | Page 19 of 20 NOTES

Rev. F | Page 20 of 20 NOTES I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors). ©2001–2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the prop erty of their respective owners. D02463-0-11/10(F)