ETC DTL2A-LC

®
®
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.
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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
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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.
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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.
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