Beta Dyne, Inc. · 110 Elm St, Unit 12 · Bridgewater, MA 02324 · Phone 508-697-1993 · Fax 508-697-2045 · www.beta-dyne.com
beta
dyne
35W HIGH-VOLTAGE
DC/DC CONVERTER
Single, Dual, Dual Independent Outputs
±120Vdc Out
35W DC/DC CONVERTER DCDC35_DS_REV02.PDF SHEET 1 OF 7
1
2
3
4
35D120/48
MADE IN USA
9
8
7
6
5
DC/DC
CONVERTER
beta
dyne
PWM
RECTIFIER
&
FILTER
ERROR
OPAM
4
1
3
P TRANS FO R ME R 5
6
7
8
9
AUX (Vo2)
+
MAIN (Vo1)
-
+
-
V ADJ
OUT
+V
ON/OFF
IN
IN
-V
SYNC L 2
Key Features
•Efficiency up to 91%
•2:1 input voltage range
•Input under/overvoltage protection
•Input to output isolation
•Soft start
•Dual short circuit protection
•500µA off-state current
•Multiple converter synchronization
•Adjustable outputs
•200kHz switching frequency
•Thermal protection
•Dual independent outputs
•Six-sided shielding
Typical Block Diagram
Functional Description Applications This family of 35W DC/DC converters is specifically designed for
telecommunications applications including xDSL remote power
feed. These converters accept wide input voltage ranges with nomi-
nal inputs of 12, 24, 48 and 120Vdc. Outputs can be single or dual
and can be set as two independent adjustable outputs of 120, ±120,
and 240Vdc. Additional features include total input to output isola-
tion, short circuit and thermal protection, soft start, under/overvolt-
age protection, adjustable outputs, and efficiency up to 91%.
Telecom
Micro-mirror Drivers
DSL Systems
Remote Feed Systems
Battery Power Systems
High Voltage Power OPAMs
Transducer Drivers
Beta Dyne, Inc. · 110 Elm St, Unit 12 · Bridgewater, MA 02324 · Phone 508-697-1993 · Fax 508-697-2045 · www.beta-dyne.com
35W DC/DC CONVERTER DCDC35_DS_REV02.PDF SHEET 2 OF 7
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Electrical Specifications
INPUT SPECIFICA TIONS
GENERAL SPECIFICATIONS
OUTPUT SPECIFICATIONS
Unless otherwise specified, all parameters are given under typical +25°C
with nominal input voltage and under full output load conditions.
Beta Dyne, Inc. · 110 Elm St, Unit 12 · Bridgewater, MA 02324 · Phone 508-697-1993 · Fax 508-697-2045 · www.beta-dyne.com
35W DC/DC CONVERTER DCDC35_DS_REV02.PDF SHEET 3 OF 7
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PHYSICAL CHARACTERISTICS
Model Selection Guide
ENVIRONMENT AL SPECIFICA TIONS
1 A dual independent output converter is generated from the single output converter by floating VO2 (see Figure 3). A 10% minimum
load is required.
2 Contact factory for -55° to +85°C operating temperature range.
3 The maximum input current at any given input range measured at minimum input voltage is given as 1.6*INOMINAL. Nominal input
current is the typical value measured at the input of the converter under full-load room temperature and nominal input voltage (12,
24, 48, and 120Vdc).
4 Measured with 10µF capacitor at the input power pins.
ORDERING GUIDE
35 __/__
Input Voltage
Output Voltage
Power
Number of Outputs (S = Single, D = Dual)
Beta Dyne, Inc. · 110 Elm St, Unit 12 · Bridgewater, MA 02324 · Phone 508-697-1993 · Fax 508-697-2045 · www.beta-dyne.com
35W DC/DC CONVERTER DCDC35_DS_REV02.PDF SHEET 4 OF 7
+Vin
ON/OFF
-Vin
SYNC
OFF
ON 0V
5V
500nS
F>200kHz
2K PS2701 1
2
3
4
C1
10-100µF
Vin F1
48Vin 2A SLOW BLOW
1A SLOW BLOW120Vin
+Vo2
-Vo2
+Vo1
-Vo1
VoADJ
5
6
7
8
9
2.2-4.7µF
200V +RL
2M
**
2200pF
CASE
**
2200pF TO .01µF 2000V
**
2200pF
35S120/48
35S120/120
** OPTIONAL PARTS
48/120Vin
F1
-
+
+
-
+Vin
ON/OFF
-Vin
SYNC
OFF
ON 0V
5V
500nS
F>200kHz
2K PS2701
F1
1
2
3
4
C1
10-100µF
Vin F1
12Vin 5A SLOW BLOW
3A SLOW BLOW24Vin
+Vo2
-Vo2
+Vo1
-Vo1
VoADJ
5
6
7
8
9
2.2-4.7µF
200V
2.2-4.7µF
200V
+RL
-RL
2M
**
2200pF
CASE
**
2200pF TO .01µF 2000V
**
2200pF
35W SERIES
** OPTIONAL PARTS
12/24Vin
+Vin
ON/OFF
-Vin
SYNC
OFF
ON 0V
5V
500nS
F>200kHz
2K PS2701
F1
1
2
3
4
C1
10-100µF
Vin F1
12Vin 5A SLOW BLOW
3A SLOW BLOW24Vin
+Vo2
-Vo2
+Vo1
-Vo1
VoADJ
5
6
7
8
9
2.2-4.7µF
200V
2.2-4.7µF
200V
RL
RL
2M
**
2200pF
CASE
**
2200pF TO .01µF 2000V
**
2200pF
35W SERIES
** OPTIONAL PARTS
12/24Vin
Vo2
+
-
Vo1
+
-
FIGURE 2. Typical connection diagram of High-Voltage 35W Dual DC/DC Converter
FIGURE 1. Typical connection diagram of High-Voltage 35W Single DC/DC Converter
FIGURE 3. Typical connection diagram of High-Voltage 35W Dual Independent Output DC/DC Converter
Beta Dyne, Inc. · 110 Elm St, Unit 12 · Bridgewater, MA 02324 · Phone 508-697-1993 · Fax 508-697-2045 · www.beta-dyne.com
35W DC/DC CONVERTER DCDC35_DS_REV02.PDF SHEET 5 OF 7
50 60 70 80
9
15
25
5
90 100 110
8
10
20
30
40
35
FREE AIR
FORCED AIR
APPROX. 100LFM
= 1.4
Po
∆
∆T°C
W
= .875
T
∆
Po
∆°C
W
PO
°C
0
0.100 [2.54]
1.800 [45.72]
2.00 [50.80]
0.700 [17.78]
0.900 [22.86]
1.100
[27.94]
0.500 [12.70]
ON/OFF
SYNC
-Vin
+Vin
Vadj
-Vo1
+Vo1
BOTTOM VIEW
-Vo2
2.00
[50.80]
Ø0.040 [1.02] (9PL)
0.10 [2.54] MIN
CASE
HEADER
+Vo2
4
3
2
1
5
6
7
8
9
0.50 [12.70] MAX.
DIMENSION ARE IN INCH(mm)
TOLERANCE: .XX ±.02(.508)
.XXX ±.01(.254)
0.400 [10.16]
0.600 [15.24]
0.800 [20.32]
1.000 [25.40]
1.200 [30.48]
niP noitcnuF
ELGNIS LAUD
1FFO/NOFFO/NO
2CNYSCNYS
3V-
NI
V-
NI
4V+
NI
V+
NI
5V+
2O
)7NIPOTTCENNOC(
V+
2O
6V-
2O
)8NIPOTTCENNOC(
V-
2O
7V+
1O
)5NIPOTTCENNOC(
V+
1O
8V-
1O
)6NIPOTTCENNOC(
V-
1O
9V
TUO
JDAV
TUO
JDA
DIMENSIONS
PIN ASSIGNMENT
FIGURE 4. Worst case derating
To trim the output voltage DOWN, connect a 5% ¼W 1.5MΩ
resistor (DO NOT GO BELOW 1MΩ) between the +V01 (Pin 7) out-
put and trim pin of the converter. To trim the output voltage UP,
connect a 5% ¼W resistor between the -V01 (Pin 8) output and
trim pins of the converter. For UP/DOWN trimming capability, con-
nect a 2MΩ potentiometer between the + and - output pins, with
the wiper arm connected to the trim pin.
The trim resistors/potentiometer can be connected at the con-
EXTERNAL SYNCHRONIZATION
A TTL signal applied at the SYNC pin of the converter will
synchronize the switching frequency of the converter to that of the
TTL input signal. The external (TTL) frequency must be equal or
higher than the converter ’s frequency. At the positive-going edge
of the applied pulse, the internal power-switching transistor turns
off and the PWM discharges its timing capacitor. At the negative-
going edge, the PWM resumes normal operation. The minimum
positive pulse width of the TTL signal must be 300nS minimum
verter output pins or the load. However, if connected at the load,
the resistance of the runs becomes part of the feedback network
which improves load regulation. If the load is some distance from
the converter , the use of #20 gauge wire is recommended to avoid
excessive voltage drop due to the resistance of the circuit paths.
See our application notes:
DC-001: Testing Transient Response in DC/DC Converters
DC-004: Thermal Consideration for DC/DC Converters
and its frequency between 190kHz and 220kHz. NOTE: Higher
frequencies will reduce the efficiency of the converter and wide
TTL pulses will force the PWM to follow the external TTL width
modulation, which may effect regulation. A high TTL signal at the
SYNC pin of the converter will turn the converter off. An internal
pull-down resistor will keep this pin low when it is not used. A pulse
differentiator (see Figure 6) can be used to shape a square wave
sync signal as shown in Figure 5.
EXTERNAL TRIMMING OF OUTPUT VOLTAGES (SINGLE AND DUAL ONLY)
Beta Dyne, Inc. · 110 Elm St, Unit 12 · Bridgewater, MA 02324 · Phone 508-697-1993 · Fax 508-697-2045 · www.beta-dyne.com
35W DC/DC CONVERTER DCDC35_DS_REV02.PDF SHEET 6 OF 7
2K
PIN#2
220pF
5µS 1N4148
FIGURE 5. Waveforms of sync signal shaping
1) CH1 2V 500nS 3) CH1 5V 500nS
2) CH2 2V 500nS 4) CH2 5V 500nS
2.2V minimum
Voltage at Pin 2
500nS
700nS
Voltage at Pin 2
5V Typical TTL level
0.8V
0.8V
SYNC SIGNAL SHAPING
As described in External Synchronization, the PWM of the
35W converter requires a TTL signal of 0.8 to 2Vdc minimum am-
plitude and minimum duration of 300nS. When such a signal is
not available (through one shot multivibrator or other pulse-shap-
ing circuits) a C-R differentiator, such as the one in Figure 6, can
be used to shape a square wave TTL signal. As is shown by the
oscillogram in Figure 5, the positive edge of the sync pulse must
be 2V minimum and the decaying exponential must reach the low
0.8Vdc in 300nS minimum from the positive edge. The parallel
diode with the resistor is a small signal switching diode or a Schottky
signal diode with 0.3 to 0.5V forward drop, it is used to clamp the
voltage at pin 2@-0.5Vdc.
FIGURE 6. Suggested pulse-shaping circuit
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Beta Dyne, Inc. · 110 Elm St, Unit 12 · Bridgewater, MA 02324 · Phone 508-697-1993 · Fax 508-697-2045 · www.beta-dyne.com
35W DC/DC CONVERTER DCDC35_DS_REV02.PDF SHEET 7 OF 7
FIGURE 7. Turn on delay with soft start
1) CH1 20V 5mS
2) CH2 100V 5mS
ON/OFF (Pin 1)
VOUT
Turn on
delay
Soft start
SHORT CIRCUIT PROTECTION
The 35W high-voltage series of converters have a dual short
circuit protection feature. At the input side of the converter, two
short circuit current comparators are used to monitor the input
current of the converter. They are biased at different voltage lev-
els; the lower threshold (LTH) comparator provides the power lim-
iting function of the converter. Under normal operating conditions,
the LTH comparator limits the output power of the converter when
the maximum output power is exceeded.
When a hard short is applied across the output of the con-
verter and the input current exceeds the set threshold of the sec-
ond comparator, the converter goes into shutdown mode, the
overcurrent latch is set and the converter is turned off. The con-
verter will turn on again when its input voltage is recycled (OFF-
ON) or if the ON/OFF pin is used to turn the converter on and off.
The time required for the ON/OFF pin to be held low is between
100mS and 800mS.
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