Datasheet

ManualsBrandsMURATA POWER SOLUTIONS ManualsPSU ComponentsDC/DC converter (print) 3 A 15 W No. of outputs: 1 x

(1) All speciﬁ cations are typical unless noted. General conditions for Speciﬁ cations are +25

deg.C, Vin=nominal, Vout=nominal (no trim installed), full rated load. Adequate airﬂ ow

must be supplied for extended testing under power.

All models are tested and speciﬁ ed with external 1µF and 22 µF paralleled output capaci-

tors and a 22 µF external input capacitor. All capacitors are low ESR types. Caps are

layout dependent These capacitors are necessary to accommodate our test equipment

and may not be required in your applications. All models are stable and regulate within

spec under no-load conditions.

(2) Input Back Ripple Current is tested and speciﬁ ed over a 5 Hz to 20 MHz bandwidth. Input

ﬁ ltering is Cin=2 x 100 µF, 100V tantalum, Cbus=1000 µF, 100V electrolytic, Lbus=1 µH.

All caps are low ESR types.

(3) Note that Maximum Power Derating curves indicate an average current at nominal input

voltage. At higher temperatures and/or lower airﬂ ow, the DC/DC converter will tolerate

brief full current outputs if the total RMS current over time does not exceed the Derating

curve. All Derating curves are presented at sea level altitude. Be aware of reduced power

dissipation with increasing altitude.

(4a) Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1,

Case 3, ground ﬁ xed conditions, Tpcboard=+25 ˚C, full output load, natural air convec-

tion.

(4b) Mean Time Before Failure is calculated using the MIL-HDBK-217N2 method, ground

benign, +25ºC., full output load, natural convection.

(5) The On/Off Control is normally controlled by a switch or open collector or open drain tran-

sistor. But it may also be driven with external logic or by applying appropriate external

voltages which are referenced to Input Common.

(6) Short circuit shutdown begins when the output voltage degrades approximately 2% from

the selected setting.

(7) The outputs are not intended to sink appreciable reverse current.

(8) “Hiccup” overcurrent operation repeatedly attempts to restart the converter with a brief,

full-current output. If the overcurrent condition still exists, the restart current will be

removed and then tried again. This short current pulse prevents overheating and damag-

ing the converter. Once the fault is removed, the converter immediately recovers normal

operation.

(9) Input Fusing: If reverse polarity is accidentally applied to the input, to ensure reverse

input protection with full output load, always connect an external input fast-blow fuse

in series with the +Vin input. Use approximately twice the full input current rating with

nominal input voltage.

(10) Regulation speciﬁ cations describe the deviation as the line input voltage or output load

current is varied from a nominal midpoint value to either extreme.

(11) CAUTION: Since the converter is mounted on the end by its pins, do not subject it to high

vibration, shock or acceleration.

(12) Output current limit and short circuit protection is non-latching. When the overcurrent

fault is removed, the converter will immediately recover.

(13) Do not exceed maximum power speciﬁ cations when adjusting the output trim. All pub-

lished speciﬁ cations are listed at rated nominal output current using published Derating

curves. The maximum power speciﬁ cations indicate brief operation before overcurrent

shutdown occurs. Note particularly that current must be limited at higher output voltage

in order to comply with maximum power requirements.

(14) At zero output current, the output may contain low frequency components which exceed

the ripple speciﬁ cation. The output may be operated indeﬁ nitely with no load.

(15) The input and output are not isolated. They share a single COMMON power and signal

return.

Notes

Trim Connections

RTRIM

RLOAD

Trim

OUT

Ground

TRIM (kΩ) =

1.182

OUT − 0.591

Output Voltage Adustment

The output voltage may be adjusted over a limited range by connecting an

external trim resistor (Rtrim) between the Trim pin and Ground. The Rtrim

resistor must be a 1/10 Watt precision metal ﬁ lm type, ±0.5% accuracy or

better with low temperature coefﬁ cient, ±100 ppm/oC. or better. Mount the

resistor close to the converter with very short leads or use a surface mount

trim resistor.

In the tables below, the calculated resistance is given. Do not exceed the

speciﬁ ed limits of the output voltage or the converter’s maximum power

rating when applying these resistors. Also, avoid high noise at the Trim

input. However, to prevent instability, you should never connect any capaci-

tors to Trim.

OKR-T/3-W12

Output Voltage Calculated Rtrim (Ω)

6 V. 218.5

5 V. 268

3.3 V. 436

2.5 V. 619

1.8 V. 978

1.5 V. 1300

1.2 V. 1940

1.0 V. 2890

0.591 V. ∞ (open)

RTRIM (k) =

_____________

(VOUT – 0.591)

1.182

Resistor Trim Equation, OKR-T/3-W12 models:

OKR-T/3 Series

Adjustable Output 3-Amp SIP-mount DC/DC Converters

MDC_OKR-T/3-W12.B05 Page 4 of 18