Datasheet

UWQ-12/17-Q48T-C Series
Wide Input, Isolated DOSA Quarter Brick
DC-DC Converters with Trim and Sense
MDC_UWQ-12-17-Q48T-C.A01 Page 16 of 17
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Figure 7. Driving the On/Off Control Pin (suggested circuit)
ON/OFF
CONTROL
-VIN
+VCC
CAUTION: Do not apply voltages to the On/Off pin when there is no input power
voltage. Otherwise the converter may be permanently damaged.
Please observe Sense inputs tolerance to avoid improper operation:
[Vout(+) −Vout(-)] − [Sense(+) −Sense(-)] ≤ 10% of Vout
Output overvoltage protection is monitored at the output voltage pin, not the
Sense pin. Therefore excessive voltage differences between Vout and Sense
together with trim adjustment of the output can cause the overvoltage protec-
tion circuit to activate and shut down the output.
Power derating of the converter is based on the combination of maximum output
current and the highest output voltage. Therefore the designer must ensure:
(Vout at pins) x (Iout)
≤ (Max. rated output power)
Emissions Performance
Murata Power Solutions measures its products for radio frequency emissions
against the EN 55022 and CISPR 22 standards. Passive resistance loads are
employed and the output is set to the maximum voltage. If you set up your
own emissions testing, make sure the output load is rated at continuous power
while doing the tests.
The recommended external input and output capacitors (if required) are includ-
ed. Please refer to the fundamental switching frequency. All of this information
is listed in the Product Specifi cations. An external discrete fi lter is installed and
the circuit diagram is shown below.
[1] Conducted Emissions Parts List
[2] Conducted Emissions Test Equipment Used
Rohde & Schwarz EMI Test Receiver (9KHz – 1000MHz) ESPC
Rohde & Schwarz Software ESPC-1 Ver. 2.20
HP11947A Transient Limiter (Agilent)
OHMITE 25W – Resistor combinations
DC Source Programmable DC Power Supply Model 62012P-100-50
Reference Part Number Description Vendor
L1 PE-62913 1mH, 6A Pulse
L3 500uH,10A, MPS 500uH,10A Murata
C8 2.2ufd Murata
C7 VZ Series
Qty 2 - Electrolytic Capacitor
22ufd, 100V
Panasonic
C16, C17 .22ufd Unknown
UWQ EMI 200W Test Card
48Vdc in, 12Vout, 17Amps
V+
V-
Black
Vin -
Vout -
Vout +Vin +
Resistive
Load
UUT
Resistive
Load
inside a
metal
container
L1
L3
C7
C16
C17
C8C8
C8
C8C8
C8
Figure 8. Conducted Emissions Test Circuit
[3] Layout Recommendations
Most applications can use the fi ltering which is already installed inside the
converter or with the addition of the recommended external capacitors. For
greater emissions suppression, consider additional fi lter components and/or
shielding. Emissions performance will depend on the user’s PC board layout,
the chassis shielding environment and choice of external components. Please
refer to Application Note GEAN02 for further discussion.
Since many factors affect both the amplitude and spectra of emissions, we
recommend using an engineer who is experienced at emissions suppression.