general description the max6629?ax6632 are local digital temperature sensors with an spi -compatible serial interface. the temperature is converted to a 12-bit + sign word with a resolution of 0.0625?/lsb. an extended temperature range provides useful readings up to +150?. these sensors are 3-wire serial interface spi compati- ble, allowing the max6629?ax6632 to be readily con- nected to a variety of microcontrollers ( cs). the max6629?ax6632 are read-only devices, simplifying their use in systems where only temperature data is required. all four digital temperature sensors require very little supply current, making them ideal for portable systems. the max6631/max6632 perform a temperature-to-digi- tal conversion once every 8s and require minimal aver- age supply current, 32? (typ). the max6629/ max6630 perform a conversion once every 0.5s and require only 200? (typ) supply current. any of these temperature sensors can perform conversions more often?p to approximately four conversions per sec- ond by reading the conversion results more often. applications features ? low power consumption 32? typ (max6631/max6632) 200? typ (max6629/max6630) ? 12-bit + sign resolution with 0.0625?/lsb ? accuracy ?? (max) from 0? to +70? ?.3? (max) from -20? to +100? ?.2? (max) from -40? to +125? ?.5? (max) at +150? ? +150? extended temperature range ? spi-compatible serial interface ? +3.0v to +5.5v supply range ? 6-pin sot23 package max6629?ax6632 12-bit + sign digital temperature sensors with serial interface ________________________________________________________________ maxim integrated products 1 gnd sck v cc 16 so 5 n.c. max6629 max6631 sot23 top view 2 34 cs n.c. sck v cc 16 so 5 gnd max6630 max6632 sot23 2 34 cs pin configurations 19-2047; rev 2; 4/04 ordering information part temp range pin- package top mark m a x6 6 2 9 m u t- t -55? to +150? 6 sot23-6 aapm m a x6 6 3 0 m u t- t -55? to +150? 6 sot23-6 aapn m a x6 6 3 1 m u t- t -55? to +150? 6 sot23-6 aapo m a x6 6 3 2 m u t- t -55? to +150? 6 sot23-6 aapp spi is a trademark of motorola, inc. v cc so gnd sck c +3v to +5.5v 0.1 f max6629 max6630 max6631 max6632 cs t ypical application circuit cellular hard disk drive hvac automotive industrial control systems for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com.
max6629?ax6632 12-bit + sign digital temperature sensors with serial interface 2 _______________________________________________________________________________________ absolute maximum ratings stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. all voltages referenced to gnd v cc ...........................................................................-0.3v, +6.0v so, sck, cs ....................................................-0.3v, v cc + 0.3v so .......................................................................-1ma to +50ma current into any pin ............................................................10ma continuous power dissipation (t a = +70?) 6-pin sot23 (derate 9.10mw/? above +70?)..........727mw junction temperature ......................................................+150? operating temperature range (note 1) ...........-55? to +150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? electrical characteristics (v cc = +3.0v to +5.5v, t a = -55? to +125?, unless otherwise noted. typical values are at v cc = +3.3v and t a = +25?.) (notes 2 and 3) parameter symbol conditions min typ max units temperature t a = room temp, v cc = +3.3v -0.8 ?.2 +0.8 0? t a +70?, v cc = +3.3v -1.0 ?.2 +1.0 -20? t a +85?, v cc = +3.3v -1.6 +0.3 +1.6 -20? t a +100?, v cc = +3.3v -2.3 +0.5 +2.3 ? -40? t a +125?, v cc = +3.3v -3.2 +0.8 +3.2 t a -55?, v cc = +3.3v -1.0 +1.5 +3.5 accuracy t a = +150?, v cc = +3.3v -5.0 +1.5 +6.5 power-supply sensitivity pss 0.2 0.6 ?/v resolution 0.0625 ? max6629, max6630, cs high 0.37 0.5 0.65 ti m e betw een c onver si on s tar ts t sample max6631, max6632, cs high 5.9 8 10.5 s conversion time t conv 180 250 320 ms power supply supply voltage range v cc 3.0 5.5 v i sd shutdown (note 3), v cc = +0.8v 5 i idle adc idle (figure 2), cs = low 6 20 supply current, sck idle i conv adc converting (figure 2) 360 650 ? max6629, max6630 200 400 average operating current i cc max6631, max6632 32 50 ? power-on reset (por) threshold v cc falling 1.6 v note 1: it is not recommended to operate the device above +125? for extended periods of time.
max6629?ax6632 12-bit + sign digital temperature sensors with serial interface _______________________________________________________________________________________ 3 electrical characteristics (continued) (v cc = +3.0v to +5.5v, t a = -55? to +125?, unless otherwise noted. typical values are at v cc = +3.3v and t a = +25?.) (notes 2 and 3) parameter symbol conditions min typ max units logic inputs ( cs , sck) logic input low voltage v il 0.3 x v cc v logic input high voltage v ih 0.7 x v cc v input leakage current i leak v in = gnd or +5.5v 1 ? ? logic outputs (so) output low voltage v ol i sink = 1.6ma 0.4 v output high voltage v oh i source = 1.6ma v cc - 0.4 v timing characteristics (notes 4 and 5) serial clock frequency f scl 5 mhz sck pulse width high t ch 100 ns sck pulse width low t cl 100 ns cs fall to sck rise t css c load = 10pf 80 ns cs fall to output enable t dv c load = 10pf 80 ns cs rise to output disable t tr c load = 10pf 50 ns sck fall to output data valid t do c load = 10pf 80 ns note 2: tested at a single temperature. specifications over temperature are guaranteed by design. note 3: max6629?ax6632 are not specifically equipped with a shutdown function. their low supply current permits powering them from the output of a logic gate. this specification is given to ensure that the max6629?ax6632 do not draw excessive currents at low supply voltages, ensuring reliable operation from a gate output. note 4: timing characteristics are guaranteed by design and are not production tested. note 5: c load = total capacitance of one bus line in picofarads.
max6629?ax6632 12-bit + sign digital temperature sensors with serial interface 4 _______________________________________________________________________________________ 100 200 150 300 250 400 350 -55 -5 20 45 -30 70 95 120 145 operating supply current vs. temperature max6629-32 toc01 temperature ( c) supply current ( a) max6629 v cc = +5.5v v cc = +4.5v v cc = +5.0v v cc = +3.0v v cc = +3.3v v cc = +3.6v 0.6 1.0 0.8 1.4 1.2 1.8 1.6 2.0 2.4 2.2 2.6 -55 -5 20 45 -30 70 95 120 145 power-on reset (por) threshold vs.temperature max6629-32 toc02 temperature ( c) power-on reset threshold (v) -4 -2 -3 0 -1 2 1 3 -55 -5 20 45 -30 70 95 120 145 temperature error vs. temperature max6629-32 toc03 temperature ( c) temperature error ( c) max6629 10 100k 10m 1k 100 10k 1m 100m temperature error vs. power-supply noise frequency max6629-32 toc04 frequency (hz) temperature error ( c) 0 4 2 6 8 10 12 v in = square wave applied to v cc with no 0.1 f capacitor v in = 250mvp-p 0 25 50 75 100 125 -2 2 0 46810 12 14 response to thermal shock max6629-32 toc05 time (s) temperature ( c) t ypical operating characteristics (v cc = +3.3v, t a = +25 ? , unless otherwise noted.) pin max6629 max6631 max6630 max6632 name function 12 n.c. no connect. connect to ground plane for better thermal performance to the pc board. 21 gnd ground 33v cc supply voltage input. bypass v cc to gnd with a 0.1? capacitor. v cc can also be powered from a logic output as long as the voltage level is greater than 3.0v and the logic output is not noisy. setting the logic output low provides a hardware shutdown mode. 44 sck serial clock input 55 cs chip-select input. enables the interface. a rising edge off cs initiates the next conversion. pulling cs low initiates an idle state. 66sose rial data output pin description
max6629?ax6632 12-bit + sign digital temperature sensors with serial interface _______________________________________________________________________________________ 5 detailed description the max6629?ax6632 are local digital temperature sensors with a serial bus. the max6629?ax6632 are typically interfaced to a ? in temperature sensing and control applications. the max6629?ax6632 convert temperature to a 12-bit + sign word with a 0.0625? lsb. the data is communicated through a simple serial interface with a cs (chip select) line, so (data) line, and sck (clock) line. this interface can be directly connected to, and is fully compatible with, spi inter- faces. this interface can also be connected to virtually any processor, which has at least three general-pur- pose input/output (gpio) lines available to implement software ?it banging. the high resolution of the max6629?ax6632 makes them especially useful in thermal control loops, hvac systems, or in any system where quick anticipation of temperature trends is useful. the max6629?ax6632 can produce temperature data in excess of +150?, although they are specified for a maximum operating temperature of +150?. this extended temperature range especially makes it useful in automotive under- hood applications. the low power consumption is also ideal in battery-operated and portable applications. the max6631/max6632 are optimized for minimum power consumption with their 8s conversions. the max6629/max6630 provide faster conversions, 0.5s, at the expense of power consumption. the low quiescent supply current enables the device to be powered from a logic line or the output of a gate where the high level exceeds 3v, as shown in figure 1. while the max6629?ax6632 are not specifically equipped with a software shutdown mode, the hardware shutdown can easily be implemented by setting the gate output to low. pulling cs low without a clock also puts the device in idle mode. take care to ensure that the logic output is not noisy, as excessive noise on v cc can affect tem- perature measurement accuracy. adc conversion sequence the max6629?ax6632 continuously convert temper- ature to digital data. setting cs low stops any conver- sion in progress, places the device in idle mode, and makes data available for reading. setting cs high starts a new conversion. cs must remain high for at least 0.3s to allow for the conversion to be completed. figure 2 shows the timing relationship between conversion time and conversion rate. spi digital interface the max6629?ax6632 are compatible with spi seri- al-interface standards (figure 3) and are designed to be read-only devices. cs ? rising edge always starts a new conversion and resets the interface. cs must stay high for a minimum of 300ms to allow the conversion to figure 2. conversion time and rate relationships max6629 max6630 max6631 max6632 0.25s adc conversion time max6631 max6632 conversion period 8s max6629 max6630 conversion period 0.5s 0.25s adc conversion time figure 1. powering the sensor from a logic gate logic line where v logic > 3v max6629 max6630 max6631 max6632 v cc so gnd sck cs
max6629?ax6632 12-bit + sign digital temperature sensors with serial interface 6 _______________________________________________________________________________________ finish. cs ? falling edge stops any conversion in progress, and data is latched into the shift register. then the data clocks out at so on sck? falling edge with the sign bit (d15) first, followed by the msb. data is sent in one 16-bit word, and cs must remain low until all 16 bits are transferred. if cs goes high in the middle of a transmission, it is necessary to wait the conversion time (less than 300ms) before attempting a new read. the serial data is composed of 12 + 1 data bits (d15?3) and 3 trailing bits (d2?0). d2 is always low, serving as the confirmation bit that the device has been communicated with. the last 2 bits, d0 and d1, are undefined and are always in high-impedance mode (table 1). the power-up state for so is high imped- ance. figure 3 shows the detailed serial timing specifi- cations for the spi port. the temperature data format is in two's complement format (table 2). power shutdown mode the max6629?ax6632 do not have a built-in power software shutdown mode. however, a power shutdown mode is easily implemented utilizing an unused logic gate. a typical cmos or ttl logic output has enough drive capability to serve as the power source if its out- put voltage level exceeds 3v, as shown in figure 1. drive the logic output low to provide a hardware shut- down mode. idle mode the max6629?ax6632 can be put into idle mode by pulling cs low. data can be clocked out when the device is in idle mode. power-on reset (por) the por supply voltage of the max6629?ax6632 is typically 1.6v. below this supply voltage the interface is inactive and the data register is set to the por state, 0?. when power is first applied and v cc rises above 1.6v (typ), the device starts to convert, although temperature reading is not recommended at v cc levels below 3.0v. figure 3. spi timing diagram d15 d0 d1 d2 d3 sck so t dv t css t do cs t tr d15 d14 d13 d12 d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 sign msb data lsb data low high-z high-z table 1. data output format table 2. temperature data format (two? complement) digital output (binary) temperature (?) d15?3 d2 d1, d0 150 0,1001,0110,0000 0xx 125 0,0111,1101,0000 0xx 25 0,0001,1001,0000 0xx 0.0625 0,0000,0000,0001 0xx 0 0,0000,0000,0000 0xx -0.0625 1,1111,1111,1111 0xx -25 1,1110,0111,0000 0xx -55 1,1100,1001,0000 0xx
applications information thermal considerations the key to accurate temperature monitoring is good thermal contact between the max6629?ax6632 package and the object being monitored. in some applications, the 6-pin sot23 package is small enough to fit underneath a socketed ?, allowing the device to monitor the ?? temperature directly. accurate temper- ature monitoring depends on the thermal resistance between the object being monitored and the max6629?ax6632 die. heat flows in and out of plas- tic packages primarily through the leads. if the sensor is intended to measure the temperature of a heat-gen- erating component on the circuit board, it should be mounted as close as possible to that component and should share supply and ground traces (if they are not noisy) with that component where possible. this maxi- mizes the heat transfer from the component to the sen- sor. the max6629/max6630 supply current is typically 200?, and the max6631/max6632 supply current is typically 32?. when used to drive high-impedance loads, the device dissipates negligible power. therefore, the die temperature is essentially the same as the package temperature. the rise in die temperature due to self-heating is given by the following formula: ? t j = p dissipation x ja where p dissipation is the power dissipated by the max6629?ax6632, and ja is the package? thermal resistance. the typical thermal resistance is +110?/w for the 6-pin sot23 package. to limit the effects of self-heat- ing, minimize the output currents. for example, if the max6629?ax6632 sink 1ma, the output voltage is guaranteed to be less than 0.4v. therefore, an addi- tional 0.4mw of power is dissipated within the ic. this corresponds to a 0.044? shift in the die temperature in the 6-pin sot23. chip information transistor count: 6475 process: bicmos max6629?ax6632 12-bit + sign digital temperature sensors with serial interface _______________________________________________________________________________________ 7 voltage reference spi-compatible interface temperature sensor 12-bit + sign ? adc max6629 max6630 max6631 max6632 so sck cs functional diagram
max6629?ax6632 12-bit + sign digital temperature sensors with serial interface maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2004 maxim integrated products printed usa is a registered trademark of maxim integrated products. 6lsot.eps f 1 1 21-0058 package outline, sot-23, 6l pa cka ge information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .)
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