datel, inc., mans eld, ma 02048 (usa) tel: (508)339-3000, (800)233-2765 fax: (508)339-6356 email: sales@datel.co m internet: www.datel.com innovation and ex c ell e n c e ? ? features applications figure 1. simpli ed schematic new isolated dc/dc converter 12-bit d/a data latch amplifier and current sensor +load +load ?load ?load control strobe (cs) clock (clk) input buffers opto isolators serial data input (sdi) latch data (ld) ground +5v supply undervoltage detection power device under test fault dtl series DTL4A model digitally programmable, 10a/150v 100 watt, electronic loads datel?s new DTL4A is an optically isolated, digitally programmable, serial-input, electronic load. it is essentially a digitally controlled current source that can sink currents from 0 to 10 amps, at loading voltages from 2.5 to 150 volts, up to a maximum power of 100 watts. the DTL4A is packaged in a thermally ef cient, 2" x 2" x 0.5" metal package that incorporates an aluminum baseplate with through-hole spacers for easy pcb mounting and/or external heat-sink attachment. the DTL4A accepts a serialized, 12-bit, cmos/ttl-compatible, digital input word easily generated by any standard digital i/o card. the DTL4A buffers and then optically isolates (500vdc) the digital input data before storing it in a register and presenting it to an on-board, 12-bit, digital-to-analog (d/a) converter. the d/a output drives a near-ideal (10m ? minimum output impedance), voltage-controlled current source. one lsb (least signi cant bit) of the d/a converter corresponds to a 2.4ma increment (0.024% of 10a) in load current. the DTL4A features a max. 3ma offset error and a max. 0.1% gain error. it has an impressive full-scale step response time of 100sec and can be operated dynamically at update rates up to 20khz. powered by a single +5v supply, the DTL4A draws a mere 150ma (maximum). while operating in the constant-current mode up to 10 amps (100w max. power), the output compliance voltage of th e DTL4A is 2.5 to 150 volts. should the output/load voltage drop below the 2.5v minimum required for proper biasing, an internal monitoring circuit activates the DTL4A's output fault line . see datel?s dtl2a-lc for compliance voltages as low as 0.6v. DTL4A?s and other electronic loads, controller boards, and software from datel are outstanding building-block components for power-supply burn-in and test systems. they are an extremely reliable, cost-effective solution that enables you to quickly con gure impressively accurate systems. 12-bit, optically isolated (500vdc), cmos/ttl-compatible serial input 0-10 amp output in 2.44ma increments 10m ? minimum output impedance output voltage to 150 volts output power to 100 watts ?ma offset error; ?.1% gain error 100?ec full-scale step response update rates to 20khz operate in parallel for higher power miniature, 2" x 2" metal package static/dynamic power-supply burn-in power-supply test and characterization battery capacity testing current-source testing capacitor discharge testing real-time load simulation
dtl series performance speci cations and ordering guide ? part number structure mechanical specifications compliance resolution logic current resolution voltage power package model (bits) compatibility (amps) (ma) ? (volts) ? (watts) (case, pinout) DTL4A 12 cmos/ttl ? 0-10 2.44 2.5-150 0-100 c24, p31 input output dtl 4 datel electronic load voltage range: 4 = 2.5 to 150v a a-series high reliability temperature deratin 11 8 9 10 1 2 4 3 5 6 7 metal case aluminum baseplate 2.00 (50.80) 2.00 (50.80) 0.20 min (5.08) 1.20 (30.48) 6 eq. sp. @ 0.200 (5.08) 1.800 (45.72) 1.640 (41.66) 1.640 (41.66) 0.50 (12.70) 0.060 0.002 dia. (1.524 0.051) 0.040 0.002 dia. (1.016 0.051) #4-40 clear thru (typ. 4 pl) bottom view 0.10 (2.54) 0.08 (2.03) 0.22 (5.59) 0.40 (10.16) pin function p31 pin function p31 1 fault 7 control strobe (cs) 2 ground 8 ?load 3 +5 volt supply 9 ?load 4 latch data (ld) 10 +load 5 serial data in (sdi) 11 +load 6 clock (clk) i/o connections contact datel for heat sink information. output power/load (watts) baseplate temperature ( c) 100 90 80 70 60 50 40 30 20 10 010 203040506070809010 0 the horizontal axis of the above chart references the temperature of the DTL4A?s alumi- num baseplate. the device can continually dissipate up to 100 watts if the baseplate is maintained at or below +50c. at +25c ambient temperature, with no heat sink or supplemental air ? ow, the DTL4A can reliably dissipate a continuous 10 watts. 2 case c24 ? typical at t a = +25c with nominal +5v supply voltage unless noted. ? the smallest increment/decrement in output current is de? ned by one lsb (least signi? cant bit) of the 12-bit digital input word. one lsb is equal to full scale (fs) divided by 4096 which corresponds to 0.0244% of 10a or 2.44ma. ? for proper operation, the unit's output/load voltage must remain within this range. voltages greater than the listed maximum can damage the device. voltages less than the minimum provide insuf? cient bias for the output stage and will result in unpredictable or no operation. see output compliance voltage and the fault line for details. ? see performance/functional speci? cations for details. 100 watt, serial-input electronic loads
DTL4A model digital inputs/outputs logic compatibility (pins 1, 4-7) cmos/ttl input logic levels: logic "1" +2 volts, minimum logic "0" +0.8 volts, maximum input logic loading: logic "1" (i ih @ v ih = 5 volts) 20a, maximum logic "0" (i il @ v il = 0 volts) ?0.6ma, maximum output logic levels: logic "1" (@ 150a) +3.5 volts, minimum logic "0" (@ 1.6ma) +0.4 volts, maximum timing see timing diagram output current: range 0-10 amps resolution ? 0.024%fs (2.44ma) accuracy ? 1%, maximum voltage range ? 2.5-150 volts power range 0-100 watts impedance 10m ? , minimum offset error ? 3ma, maximum gain error 0.1%, maximum isolation voltage: digital inputs/output to load 500vdc, minimum any pin to case 500vdc, minimum isolation resistance 100m ? , minimum dynamic performance output slew rate 10a/sec, minimum output settling time ? 100sec digital input update rate to 20khz power requirements power supply range (+v cc , pin 3) +4.75-5.25 volts (+5v nominal) power supply current 110ma typ., 150ma max. environmental operating temperature ? ?40 to +100c (case) storage temperature ?40 to +125c (ambient) humidity (non-condensing) to 95% altitude above sea level 10,000 feet physical dimensions 2" x 2" x 0.5" (51 x 51 x 12.7mm) shielding 6-sided (connected to pin 2) case material tin-plated steel shell with aluminum baseplate pin material brass, solder coated mounting holes through-hole spacers, #4-40 clearance weight 1.9 ounces (54 grams) ? the smallest increment/decrement in output current is de? ned by one lsb (least signi? cant bit) of the 12-bit digital input word. one lsb is equal to full scale (fs) divided by 4096 which corresponds to 0.0244% of 10a or 2.44ma. ? for proper operation, the unit's output/load voltage must remain within this range. voltages greater than the listed maximum can damage the device. voltages less than the minimum provide insuf? cient bias for the output stage and will result in unpredictable or no operation. see output compliance voltage and the fault line for details. ? offset error is de? ned as the current sunk/sourced by the DTL4A?s output, under any output voltage conditions, when the digital input word is all "0's." ? full scale step (10 amps) settling to within 2.44ma of its ? nal value. ? see temperature derating. ? applies over all speci? ed ranges/combinations of load voltage/current, operating temperature, and v cc . power supply voltage (+v cc , pin 3) ?0.5 to +5.5 volts digital input voltag e (pins 4-7) ?0.5 to +5.5 volts output reverse-polarity protection no protection output overvoltage protection no protection output undervoltage protection yes (see fault line) case temperature +105c storage temperature (ambient) ?40 to +125c lead temperature (soldering, 10 sec.) +300c absolute maximum ratings these are stress ratings. exposure of devices to any of these conditions may adversely affect long-term reliability. proper operation under conditions other than those listed in the performance/functional speci? cations table is not implied. overview the DTL4A is a digitally programmable, cmos/ttl-compatible, serial-input current sink. it?s output/load current range is 0 to 10 amps (in 2.44ma increments), over a compliance voltage range of 2.5 to 150 volts and an output/ load power range of 0 to 100 watts. the device?s digital i/o coding is straight binary (see table below). a digital input of all "0?s" forces a load current of 0 amps. a digital input of all "1?s" forces a load current of 9.99756 amps. in a typical power-supply test or burn-in application, the output pins of the device under test (dut) are connected to the DTL4A?s +load (pins 10 and 11) and ?load (pins 8 and 9) outputs. the DTL4A?s operation is controlled by its four digital input lines (serial data in, clock, latch data and control strobe). technical notes msb lsb DTL4A 1111 1111 1111 9.9976 1100 0000 0000 7.5000 1000 0000 0000 5.0000 0111 1111 1111 4.9976 0100 0000 0000 2.5000 0010 0000 0000 1.2500 0000 0000 0001 0.0024 0000 0000 0000 0.0000 serial input data word load current (amps) mapping of the serial-input data to load current 3 100 watt, serial-input electronic loads performance/functional speci cations typical @ t a = +25c with nominal +5v supply voltage, unless noted.
dtl series serial data following initialization, the 12-bit digital word representing the desired output current is applied to the sdi pin. the serial data should appear starting with the most signi? cant bit (msb, bit 1, d11) and ending with the least signi? cant bit (lsb, bit 12, d0). with each data bit present and stable on the sdi line, the clk must be toggled through a low-to-high transition to register that bit. twelve rising clock edges, at rates up to 500khz, are required to clock all 12 digital bits into the DTL4A?s input register. latching data and presenting it to the d/a after loading the lsb, the serial data word is latched by bringing the control strobe (pin 7) high and then toggling the latch data pin (pin 4) through a high-low-high sequence. approximately 100sec later, the output current will settle to its ? nal desired value. software: c language the following steps describe a typical timing sequence when using the DTL4A?s 4 digital inputs and a programming language such as c. using 4 bits of a typical 8-bit port, assign bit_0 to the control strobe (cs, pin 7), bit_1 to latch data (ld, pin 4), bit_2 to serial data in (sdi, pin 5), and bit_3 to the clock (clk, pin 6). 1. initialize with control strobe, latch data, and clock high: bit_0 = 1, bit_1 = 1, bit_2 = x (don?t care), bit_3 = 1 2. bring the control strobe low. bit_0 = 0 3. apply the msb (d11) of the serial data word to serial data in. bit_2 = 0 or 1 4. toggle the clock high-low-high. bit_3 = 1 to 0 to 1 5. apply d10 of the serial data word to serial data in. bit_2 = 0 or 1 6. toggle the clock high-low-high. bit_3 = 1 to 0 to 1 7. repeat the process for remaining data bits d9 through d0. 8. drive the control strobe high. bit_0 = 1 9. toggle the latch data input high-low-high. bit_1 = 1 to 0 to 1. output compliance voltage and the fault line for proper operation, the DTL4A?s output/load voltage must always be between 2.5 and 150 volts. the device cannot be used to directly load low-voltage, e.g. 1.8v or 2.5v, power components or to simulate a true short circuit (0 volts). voltages greater than 150v can damage the device. voltages <2.5v will result in insuf? cient biasing of the output current source and consequently unpredict- able or no operation. accordingly, we have installed an internal output/load-voltage monitoring circuit. if the output/load voltage drops below 2.5v and the DTL4A?s output is at risk of becoming disabled, the fault line activates. the fault line is an optically isolated, active-low function with an open-collector output (internal 10k ? pull-up resistor to +5v). under normal conditions, its output is high (logic "1"). under fault conditions (v out < 2.5v), its output drops to a logic "0." there is no output/load-voltage monitoring circuit for voltages greater than 150v, and operation above 150v can damage the device. an "offset supply" can be inserted between the DTL4A?s ?load output (pins 8 and 9) and the power device under test (dut) to "translate" the DTL4A?s 147.5v output/load voltage range. the offset supply must have adequate current capabilities and be con- nected with the polarities indicated in figure 2 below. under no circumstances should the voltage across the DTL4A?s output be allowed to experience a polarity reversal. if a 5v/20a offset supply is inserted as shown, the range of dut voltages will be ?2.5 to +145 volts. such a con? guration can be used for true short-circuit testing. a mechanical relay can be used to short the outputs of the dut while the offset supply ensures the DTL4A always sees at least 5 volts across its outputs. thermal considerations the DTL4A can reliably handle 100w loads if its case temperature is maintained at or below +50c. with no heat sinking or auxiliary cooling, the device can only handle loads up to 10 watts. please refer to the temperature derating curve for additional information. datel?s electronic load applica- tions engineers can assist you in developing heat-sink solutions for your higher-power DTL4A applications. please contact us for details. initialization preparing the DTL4A to accept new digital data is accomplished by applying logic "1's" to control strobe (cs, pin 7), latch data (ld, pin 4) and clock (clk, pin 6) with all signals present and stable for a minimum of 1sec. during this interval, it does not matter whether or not data is present on the serial data in (sdi, pin 5) line. +load DTL4A ?load 11 10 9 8 5v ? ? + + dut short circuit relay figure 2. an "offset supply" enables true short-circuit testing 4 100 watt, serial-input electronic loads
DTL4A model datel makes no representation that the use of its products in the circuits described herein, or the use of other technical info rmation contained herein, will not infringe upon existing or future patent rights. the descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. speci? cations are subject to change without notice. the datel logo is a registered datel, inc. trademark. datel (uk) ltd. tadley, england tel: (01256)-880444 datel s.a.r.l. montigny le bretonneux, france tel: 01-34-60-01-01 datel gmbh mnchen, germany tel: 89-544334-0 datel kk tokyo, japan tel: 3-3779-1031, osaka tel: 6-354-2025 datel, inc. 11 cabot boulevard, mans? eld, ma 02048-1151 tel: (508) 339-3000 (800) 233-2765 fax: (508) 339-6356 internet: www.datel.com email: sales@datel.com ds-0478 9/00 iso 9001 registered innovation and ex c ell e n c e ? ? figure 3. DTL4A timing diagram clk ? ? 2 00 khz t in 1 ? ? sec t cl = t ch 1 ? ? sec t css 1 ? ? sec t csh 1 ? ? sec t ld1 2 ? ? sec t ld2 2 ? ? sec t ldw 2 ? ? sec t ds 0.5 ? ? sec t dh 0.5 ? ? sec timing min. typ. max. units 5 sdi t dh t ds t css t in t cl t ch t csh t ld2 t ld1 t ldw d11 d10 d9 d8 d7 d6 d5 d4 d2 d3 d1 d0 clk cs ld 100 watt, serial-input electronic loads
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