® ® NEW INNOVATION and EXCELLENCE DTL Series DTL2A-LC Model 100 Watt, Digitally Programmable Low-Voltage, Electronic Loads DATEL’s new DTL2A-LC is an optically isolated, digitally programmable, serialinput electronic load designed for use in burn-in, characterization and test of today’s low-voltage power supplies and power components. The DTL2A-LC is essentially a digitally controlled current source that can sink currents from 0 to 20 Amps, at loading voltages as low as 0.6 Volts, up to a maximum power of 100 Watts. The DTL2A-LC accepts a serialized, 12-bit, CMOS/TTL-compatible, digital input word easily supplied by any standard digital I/O card. The DTL2A-LC optically isolates (500Vdc) the digital data, latches it, and presents it to an on-board, 12-bit, digitalto-analog (D/A) converter. The D/A output drives a near-ideal (10MΩ min. output impedance), voltage-controlled current source. One LSB (least significant bit) of the D/A corresponds to a 5mA increment (0.025% of 20A) in load current. The DTL2A-LC guarantees a ±10mA max. offset error and a ±0.4% max. gain error. It has an impressive full-scale step response time of 100µsec and can be updated at rates to 20kHz. The DTL2A-LC operates from a single +5V and draws a mere 150mA. It is housed in a thermally efficient, 2" x 2" x 0.5" metal package that has an aluminum baseplate with through-hole spacers for easy pcb mounting and/or heat-sink attachment. When operating with constant currents up to 20 Amps, the DTL2A-LC has an output compliance voltage of 0.6 to 50 Volts. Should the output/load voltage drop below the 0.6V minimum required for proper biasing, an internal monitoring circuit activates the DTL2A-LC's output Fault line. DATEL’s electronic loads and their companion controller boards and software are outstanding building-block components for power-supply (AC/DC and DC/DC converters) and power-component (diodes, FET’s, etc.) burn-in and test systems. They are an extremely reliable, cost-effective solution that enables you to quickly configure flexible, impressively accurate systems. Features ■ 12-bit, optically isolated (500Vdc), CMOS/TTL-compatible serial input ■ Output load voltages as low as 0.6 Volts ■ Output current 0-20A in 5mA increments ■ Output power to 100 Watts ■ 10MΩ minimum output impedance ■ ±10mA offset error; ±0.4% gain error ■ 100µsec full-scale step response ■ Operate in parallel for higher power ■ Miniature, 2" x 2" metal package Applications ■ Static/dynamic power-supply burn-in ■ Power-supply test and characterization ■ Battery capacity testing ■ Current-source testing ■ Capacitor discharge testing ■ Real-time load simulation INPUT BUFFERS OPTO ISOLATORS CONTROL STROBE (CS) +LOAD +LOAD CLOCK (CLK) DATA LATCH SERIAL DATA INPUT (SDI) 12-BIT D/A AMPLIFIER AND CURRENT SENSOR POWER DEVICE UNDER TEST –LOAD LATCH DATA (LD) +5V SUPPLY GROUND –LOAD UNDERVOLTAGE DETECTION ISOLATED DC/DC CONVERTER FAULT Figure 1. Simplified Schematic DATEL, Inc., Mansfield, MA 02048 (USA) · Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 · Email: [email protected] · Internet: www.datel.com DTL Series 1 0 0 WAT T, L OW- VO LTAG E E L E C T R O N I C L OA D S Performance Specifications and Ordering Guide ➀ Output Input Model Resolution (Bits) Logic Compatibility Current (Amps) Resolution (mA) ➁ Compliance Voltage (Volts) ➂ Power (Watts) Package (Case, Pinout) DTL2A-LC 12 CMOS/TTL ➃ 0-20 5 0.6-50 0-100 C24, P31 ➀ Typical at TA = +25°C with nominal +5V supply voltage unless noted. ➁ The smallest increment/decrement in output current is defined by one LSB (least significant 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 20A or 4.88mA. ➂ 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 insufficient bias for the output stage and will result in unpredictable or no operation. See Output Compliance Voltage and the Fault Line for details. ➃ See Performance/Functional Specifications for details. M E C H A N I C A L S P E C I F I C AT I O N S PA R T N U M B E R S T R U C T U R E 2.00 (50.80) 2 A - LC DTL Low Compliance Voltage DATEL Electronic Load METAL CASE 0.50 (12.70) A-Series High Reliability ALUMINUM BASEPLATE Case C24 0.060 ±0.002 DIA. (1.524 ±0.051) 0.040 ±0.002 DIA. (1.016 ±0.051) Voltage Range: 2 = 0.6 to 50V 0.20 MIN (5.08) 1.800 (45.72) 0.10 (2.54) 1.640 (41.66) 0.08 (2.03) T E M P E R AT U R E D E R AT I N 8 7 100 6 90 80 Output Power/Load (Watts) 5 1.20 (30.48) 6 EQ. SP. @ 0.200 (5.08) 9 2.00 1.640 (41.66) (50.80) 4 3 10 2 70 1 11 60 0.40 (10.16) 50 BOTTOM VIEW #4-40 CLEAR THRU (TYP. 4 PL) 40 0.22 (5.59) 30 I/O Connections 20 10 0 10 20 30 40 50 60 70 80 90 100 Baseplate Temperature (°C) The horizontal axis of the above chart references the temperature of the DTL2A-LC’s aluminum baseplate. The device can continually dissipate up to 100 Watts if the baseplate is maintained at or below +50°C. At +25°C ambient temperature, with no heat sink or supplemental air flow, the DTL2A can reliably dissipate a continuous 10 Watts. 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) Contact DATEL for Heat Sink information. 2 DTL2A-LC Model 1 0 0 WAT T, L OW- VO LTAG E E L E C T R O N I C L OA D S Performance/Functional Specifications Typical @ TA = +25°C with nominal +5V supply voltage, unless noted. ➀ The smallest increment/decrement in output current is defined by one LSB (least significant 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 20A or 4.88mA. ➁ 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 than the minimum provide insufficient bias for the output stage and will result in unpredictable or no operation. See Output Compliance Voltage and the Fault Line for details. ➂ Offset error is defined as the current sunk/sourced by the DTL2A’s output, under any output voltage conditions, when the digital input word is all "0's." ➃ Full scale step (20 Amps) settling to within ±5mA of its final value. ➄ See Temperature Derating. ➅ Applies over all specified ranges/combinations of load voltage/current, operating temperature, and VCC. Digital Inputs/Outputs Logic Compatibility (Pins 1, 4-7) CMOS/TTL Input Logic Levels: Logic "1" Logic "0" +2 Volts, minimum +0.8 Volts, maximum Input Logic Loading: Logic "1" (IIH @ VIH = 5 Volts) Logic "0" (IIL @ VIL = 0 Volts) 20µA, maximum –0.6mA, maximum Output Logic Levels: Logic "1" (@ 150µA) Logic "0" (@ 1.6mA) +3.5 Volts, minimum +0.4 Volts, maximum Timing See Timing Diagram Absolute Maximum Ratings Output Power Supply Voltage (+VCC, Pin 3) –0.5 to +5.5 Volts Current: Range Resolution ➀ Accuracy ➅ Digital Input Voltage (Pins 4-7) –0.5 to +5.5 Volts 0-20 Amps 0.024%FS (4.88mA) ±3%, maximum Output Reverse-Polarity Protection No protection Output Overvoltage Protection No protection Output Undervoltage Protection Yes (See Fault Line) Case Temperature +105°C Storage Temperature (Ambient) –40 to +125°C +300°C Voltage Range ➁ 0.6-50 Volts Power Range 0-100 Watts Impedance 10MΩ, minimum Offset Error ➂ ±10mA, maximum Gain Error ±0.4%, maximum Lead Temperature (Soldering, 10 sec.) Isolation Voltage: Digital Inputs/Output to ±Load Any Pin to Case 500Vdc, minimum 500Vdc, minimum 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 Specifications Table is not implied. Isolation Resistance 100MΩ, minimum Dynamic Performance Output Slew Rate TECHNICAL NOTES ±10A/µsec, minimum Output Settling Time ➃ 100µsec Digital Input Update Rate to 20kHz Overview The DTL2A-LC is a digitally programmable, CMOS/TTL-compatible, serialinput current sink. It’s output/load current range is 0 to 20 Amps (in 4.88mA increments), over a compliance voltage range of 0.6 to 50 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 19.995 Amps. Power Requirements Power Supply Range (+VCC, Pin 3) +4.75-5.25 Volts (+5V nominal) Power Supply Current 110mA typ., 150mA max. Environmental Operating Temperature ➄ –40 to +100°C (Case) Storage Temperature –40 to +125°C (Ambient) Humidity (Non-condensing) to 95% Altitude Above Sea Level In a typical power-supply test or burn-in application, the output pins of the device under test (DUT) are connected to the DTL2A-LC’s +Load (pins 10 and 11) and –Load (pins 8 and 9) outputs. The DTL2A-LC's operation is controlled by its four digital input lines (Serial Data In, Clock, Latch Data and Control Strobe). 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) Serial Input Data Word MSB Load Current (Amps) LSB DTL2A 1111 1111 1111 19.995 1100 0000 0000 15.000 1000 0000 0000 10.000 0111 1111 1111 9.995 0100 0000 0000 5.000 0010 0000 0000 2.500 0000 0000 0001 0.005 0000 0000 0000 0.000 Mapping of the Serial-Input Data to Load Current 3 DTL Series 1 0 0 WAT T, L OW- VO LTAG E E L E C T R O N I C L OA D S Initialization Output Compliance Voltage and the Fault Line Preparing the DTL2A-LC 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 1µsec. During this interval, it does not matter whether or not data is present on the Serial Data In (SDI, pin 5) line. For proper operation, the DTL2A-LC’s output/load voltage must always be between 0.6 and 50 Volts. The device cannot be used to directly load extremely low-voltage (<0.6V) power components or to simulate a true short circuit (0 Volts). Voltages greater than 50V can damage the device. Voltages <0.6V will result in insufficient biasing of the output current source and consequently unpredictable or no operation. Accordingly, we have installed an internal output/load-voltage monitoring circuit. If the output/load voltage drops below 0.6V and the DTL2A-LC’s output is at risk of becoming disabled, the Fault line activates. 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 significant bit (MSB, bit 1, D11) and ending with the least significant 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 DTL2A-LC’s input register. The Fault line is an optically isolated, active-low function with an opencollector output (internal 10kΩ pull-up resistor to +5V). Under normal conditions, its output is high (logic "1"). Under fault conditions (VOUT < 2.5V), its output drops to a logic "0." There is no output/load-voltage monitoring circuit for voltages greater than 50V, and operation above 50V can damage the device. Latching Data and Presenting It to the D/A Software: C Language An "offset supply" can be inserted between the DTL2A-LC’s –Load output (pins 8 and 9) and the power device under test (DUT) to "translate" the DTL2A-LC’s 49.4V output/load voltage range. The offset supply must have adequate current capabilities and be connected with the polarities indicated in Figure 2 below. Under no circumstances should the voltage across the DTL2A-LC’s output be allowed to experience a polarity reversal. The following steps describe a typical timing sequence when using the DTL2ALC’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). If a 5V/20A offset supply is inserted as shown, the range of DUT voltages will be –4.4 to +45 Volts. Such a configuration 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 DTL2A-LC always sees at least 5 Volts across its outputs. 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 100µsec later, the output current will settle to its final desired value. 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 +LOAD 11 10 2. Bring the Control Strobe low. BIT_0 = 0 + DTL2A-LC 3. Apply the MSB (D11) of the serial data word to Serial Data In. BIT_2 = 0 or 1 DUT 5V 9 –LOAD – + SHORT CIRCUIT RELAY – 8 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 Figure 2. An "Offset Supply" Enables True Short-Circuit Testing 6. Toggle the Clock high-low-high. BIT_3 = 1 to 0 to 1 Thermal Considerations 7. Repeat the process for remaining data bits D9 through D0. The DTL2A-LC can reliably handle 100W loads if its case temperature is maintained at or below +50°C. 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 Applications Engineers can assist you in developing heat-sink solutions for your higher-power DTL2A-LC applications. Please contact us for details. 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. 4 DTL2A-LC Model 1 0 0 WAT T, L OW- VO LTAG E E L E C T R O N I C L OA D S tdh D11 SDI D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 tds tin CLK tcl tcss tcsh tch CS tld1 tld2 LD tldw Timing Min. Typ. Max. Units CLK – – 500 kHz tin 1 – – µsec tcl = tch tcss tcsh tld1 tld2 tldw tds tdh 1 – – µsec 1 – – µsec 1 – – µsec 2 – – µsec 2 – – µsec 2 – – µsec 0.5 – – µsec 0.5 – – µsec Figure 3. DTL2A-LC Timing Diagram ® ® INNOVATION and EXCELLENCE ISO 9001 REGISTERED DS-0474A 9/00 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 München, Germany Tel: 89-544334-0 DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-354-2025 DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 Internet: www.datel.com Email: [email protected] DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information 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. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark. 5