OBSOLETE PRODUCT
DTL Series
DTL3A Model
Digitally Programmable, 2A/200V
100 Watt, Electronic Loads
Features
■
12-bit, optically isolated (500Vdc),
CMOS/TTL-compatible serial input
0-2 Amp output in 500µA increments
Output voltage to 200 Volts
Output power to 100 Watts
10MΩ minimum output impedance
±500µA offset error; ±0.1% gain error
100µsec full-scale step response
Update rates to 20kHz
Operate in parallel for higher power
Miniature, 2" x 2" metal package
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Applications
■
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Static/dynamic power-supply burn-in
Power-supply test and characterization
Battery capacity testing
Current-source testing
Capacitor discharge testing
Real-time load simulation
DATEL’s new DTL3A is a digitally controlled, optically isolated, serial-input elec-
tronic load that offers high compliance voltage and unprecedented control over low-
level currents. The DTL3A is essentially a computer controlled current source that
sinks currents from 0 to 2 Amps, at loading voltages from 2.5 to 200 Volts, up to a
maximum power of 100 Watts. The DTL3A accepts a serialized, 12-bit, CMOS/TTL
digital input word, optically isolates (500Vdc) the data, latches it, and presents it to an
on-board, 12-bit, digital-to-analog (D/A) converter. The D/A output drives a near-ideal
(10MΩ output impedance), voltage-controlled current source.
One LSB (least signi cant bit) of the D/A corresponds to a mere 500µA (0.025% of
2A) of load current. Combined with the DTL3A’s ±500µA max. offset error and ±0.1%
max. gain error, this precise digital control gives users extraordinary command over
the generation of low-level load currents. A 100mA current, for example, is guaranteed
to have ±1mA accuracy over all speci ed load-voltage conditions.
The DTL3A has impressive speed performance. Digital update rates to 20kHz
are possible, and settling time for a full 2A step is 100µsec. The unit is housed in a
thermally ef cient, 2" x 2" x 0.5" metal package that has an aluminum baseplate with
through-hole spacers for easy pcb mounting and/or external heat-sink attachment.
The DTL-3A has an output compliance-voltage requirement 2.5 to 200V. Should
the output/load voltage drop below the 2.5V minimum required for proper biasing,
an internal monitoring circuit activates the DTL3A's output Fault line. See DATEL’s
DTL2A-LC for compliance voltages as low as 0.6V.
DATEL’s electronic loads, controller boards and companion software are outstand-
ing building-block components for power-supply (AC/DC and DC/DC) 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 con gure exible, impres-
sively accurate systems.
INPUT
BUFFERS
CONTROL STROBE (CS)
OPTO
ISOLATORS
+LOAD
CLOCK (CLK)
DATA
LATCH
12-BIT
D/A
AMPLIFIER
AND
CURRENT
SENSOR
–LOAD
LATCH DATA (LD)
–LOAD
+LOAD
POWER DEVICE
UNDER TEST
SERIAL DATA INPUT (SDI)
+5V SUPPLY
GROUND
ISOLATED
DC/DC
CONVERTER
UNDERVOLTAGE
DETECTION
FAULT
Figure 1. Simplified Schematic
DTL Series
1 0 0 WAT T, H I G H - VO LTAG E E L E C T R O N I C L OA D S
Performance Specifications and Ordering Guide
Input
Resolution
(Bits)
12
Logic
Compatibility
CMOS/TTL
➃
➀
Output
Model
DTL3A
Current
(Amps)
0-2
Resolution
(mA)
➁
0.5
Compliance
Voltage
(Volts)
➂
2.5-200
Power
(Watts)
0-100
Package
(Case, Pinout)
C24, P31
➀
Typical at T
A
= +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 2A or 488µA.
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.
PA R T N U M B E R S T R U C T U R E
M E C H A N I C A L S P E C I F I C AT I O N S
DTL
DATEL
Electronic Load
3 A
A-Series
High Reliability
0.50
(12.70)
2.00
(50.80)
ALUMINUM BASEPLATE
METAL CASE
Case C24
Voltage Range:
3 = 2.5 to 200V
0.20 MIN
(5.08)
0.040 ±0.002 DIA.
(1.016 ±0.051)
1.800
(45.72)
1.640
(41.66)
0.060 ±0.002 DIA.
(1.524 ±0.051)
0.10
(2.54)
0.08
(2.03)
T E M P E R AT U R E D E R AT I N
7
100
90
80
8
6
1.20
(30.48)
6 EQ. SP. @
0.200 (5.08)
5
4
3
2
1
9
2.00
1.640
(41.66) (50.80)
Output Power/Load (Watts)
10
70
60
50
40
30
20
11
0.40
(10.16)
BOTTOM VIEW
#4-40 CLEAR THRU
(TYP. 4 PL)
0.22
(5.59)
I/O Connections
Pin
Function P31
Fault
Ground
+5 Volt Supply
Latch Data (LD)
Serial Data In (SDI)
Clock (CLK)
Pin
7
8
9
10
11
Function P31
Control Strobe (CS)
–Load
–Load
+Load
+Load
1
2
0
10
20
30
40
50
60
70
80
90
100
10
Baseplate Temperature (°C)
3
4
5
The horizontal axis of the above chart references the temperature of the DTL3A’s alumi-
num 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 DTL3A can reliably dissipate a continuous 10 Watts.
6
Contact DATEL for Heat Sink information.
2
1 0 0 WAT T, H I G H - VO LTAG E E L E C T R O N I C L OA D S
DTL3A Model
Performance/Functional Specifications
Typical @ T
A
= +25°C with nominal +5V supply voltage, unless noted.
Digital Inputs/Outputs
Logic Compatibility
(Pins 1, 4-7)
Input Logic Levels:
Logic "1"
Logic "0"
Input Logic Loading:
Logic "1" (I
IH
@ V
IH
= 5 Volts)
Logic "0" (I
IL
@ V
IL
= 0 Volts)
Output Logic Levels:
Logic "1" (@ 150µA)
Logic "0" (@ 1.6mA)
Timing
Current:
Range
Resolution
➀
Accuracy
➅
Voltage Range
➁
Power Range
Impedance
Offset Error
➂
Gain Error
Isolation Voltage:
Digital Inputs/Output to ±Load
Any Pin to Case
Isolation Resistance
Output Slew Rate
Output Settling Time
➃
Digital Input Update Rate
Power Supply Range
(+V
CC
, Pin 3)
Power Supply Current
Operating Temperature
➄
Storage Temperature
Humidity (Non-condensing)
Altitude Above Sea Level
Dimensions
Shielding
Case Material
Pin Material
Mounting Holes
Weight
CMOS/TTL
+2 Volts, minimum
+0.8 Volts, maximum
20µA, maximum
–0.6mA, maximum
+3.5 Volts, minimum
+0.4 Volts, maximum
See Timing Diagram
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 2A or 488µA.
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 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 DTL3A’s output, under any output
voltage conditions, when the digital input word is all "0's."
➃
Full scale step (2 Amps) settling to within ±0.5mA of its final value.
➄
See Temperature Derating.
➅
Applies over all specified ranges/combinations of load voltage/current, operating temperature,
and V
CC
.
Absolute Maximum Ratings
Power Supply Voltage
(+V
CC
, Pin 3)
Digital Input Voltage
(Pins 4-7)
–0.5 to +5.5 Volts
–0.5 to +5.5 Volts
No protection
No protection
Yes (See Fault Line)
+105°C
–40 to +125°C
+300°C
Output
0-2 Amps
0.024%FS (488µA)
±1%, maximum
2.5-200 Volts
0-100 Watts
10MΩ, minimum
±0.5mA, maximum
±0.1%, maximum
500Vdc, minimum
500Vdc, minimum
100MΩ, minimum
Output Reverse-Polarity Protection
Output Overvoltage Protection
Output Undervoltage Protection
Case Temperature
Storage Temperature
(Ambient)
Lead Temperature
(Soldering, 10 sec.)
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.
Dynamic Performance
±10A/µsec, minimum
100µsec
to 20kHz
TECHNICAL NOTES
Overview
The DTL3A is a digitally programmable, CMOS/TTL-compatible, serial-input
current sink. It’s output/load current range is 0 to 2 Amps (in 488µA
increments), over a compliance voltage range of 2.5 to 200 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 1.9995 Amps.
In a typical power-supply test or burn-in application, the output pins of the
device under test (DUT) are connected to the DTL3A’s +Load (pins 10 and 11)
and –Load (pins 8 and 9) outputs. The DTL3A’s operation is controlled by its
four digital input lines (Serial Data In, Clock, Latch Data and Control Strobe).
Serial Input Data Word
MSB
1111
1100
1000
0111
0100
0010
0000
0000
1111
0000
0000
1111
0000
0000
0000
0000
LSB
1111
0000
0000
1111
0000
0000
0001
0000
Power Requirements
+4.75-5.25 Volts (+5V nominal)
110mA typ., 150mA max.
Environmental
–40 to +100°C (Case)
–40 to +125°C (Ambient)
to 95%
10,000 feet
Physical
2" x 2" x 0.5" (51 x 51 x 12.7mm)
6-sided (Connected to pin 2)
Tin-plated steel shell with
aluminum baseplate
Brass, solder coated
Through-hole spacers, #4-40 clearance
1.9 ounces (54 grams)
Load Current (Amps)
DTL3A
1.9995
1.5000
1.0000
0.9995
0.5000
0.2500
0.0005
0.0000
Mapping of the Serial-Input Data to Load Current
3
DTL Series
1 0 0 WAT T, H I G H - VO LTAG E E L E C T R O N I C L OA D S
Initialization
Preparing the DTL3A 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.
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 DTL3A’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 100µsec later, the output current will
settle to its final desired value.
Software: C Language
The following steps describe a typical timing sequence when using the
DTL3A’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 DTL3A’s output/load voltage must always be
between 2.5 and 200 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 200V can damage the device. Voltages
<2.5V 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 2.5V and the DTL3A’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 10kΩ pull-up resistor to +5V). Under normal condi-
tions, 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 200V, and operation above 200V can damage the
device.
An "offset supply" can be inserted between the DTL3A’s –Load output (pins
8 and 9) and the power device under test (DUT) to "translate" the DTL3A’s
197.5V 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 DTL3A’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 +195 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 DTL3A always sees at least 5 Volts
across its outputs.
+LOAD
11
10
+
DUT
5V
9
+
–
SHORT
CIRCUIT
RELAY
DTL3A
–LOAD
8
–
Figure 2. An "Offset Supply" Enables
True Short-Circuit Testing
Thermal Considerations
The DTL3A 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 Applica-
tions Engineers can assist you in developing heat-sink solutions for your
higher-power DTL3A applications. Please contact us for details.
4
1 0 0 WAT T, H I G H - VO LTAG E E L E C T R O N I C L OA D S
DTL3A Model
t
dh
SDI
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
t
ds
t
in
CLK
t
css
t
cl
t
ch
t
csh
CS
t
ld1
LD
t
ld2
t
ldw
Timing
CLK
Min.
–
1
1
1
1
2
2
2
0.5
0.5
Typ.
–
–
–
–
–
–
–
–
–
–
Max.
200
–
–
–
–
–
–
–
–
–
Units
Hz
µsec
µsec
µsec
µsec
µsec
µsec
µsec
µsec
µsec
t
in
t
cl
= t
ch
t
css
t
csh
t
ld1
t
ld2
t
ldw
t
ds
t
dh
Figure 3. DTL3A Timing Diagram
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
This product is subject to the following
operating requirements
and the
Life and Safety Critical Application Sales Policy:
Refer to:
http://www.murata-ps.com/requirements/
Murata Power Solutions, Inc. 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.
© 2012 Murata Power Solutions, Inc.
www.murata-ps.com/support
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