www.murata-ps.com
UNR D3 SERIES
Single Output, Non-Isolated, 3.3V
IN
to 1.5/1.8/2.5V
OUT
8 and 10 Amp DC/DC Converters
OBSOLETE PRODUCT
Features
■
■
■
■
■
■
■
■
■
■
■
Last time buy: 3 March 2014
Click
logic are demanding more 1.5V, 1.8V or 2.5V
If your DSP and CPLD core
here for more information.
current from your 3.3V system, don’t pay to derive more isolated power from your
intermediate dc bus. Murata Power Solutions’ new, 3.3V-input, UNR "D3" models
derive 10 Amps
of low-voltage current right from your 3.3V supply. These non-isolated power
converters exploit full synchronous rectification, planar magnetics, and 100% auto-
mated assembly to deliver high efficiencies (to 89%), low noise (typically 80mVp-p),
and low costs. Housed in 1" x 2" shielded metal cases, UNR D3’s offer standard
through-hole ("T" models) or SMT ("SM" models) packaging.
The new "gull-wing" SMT packages (with metal shells and non-conductive
plastic baseplates) weigh less than 40 grams and can withstand peak lead tem-
peratures up to +300°C.
These versatile DC/DC’s are fully line (±0.1% max.) and load (±0.5% max.)
regulated. They feature quick transient response (25µsec), user-optional on/off
control (for power sequencing), and output overcurrent detection and shutdown
("hiccup" technique with auto-recovery). Their impressive guaranteed efficiencies
enable them to deliver fully rated output power from –40 to +50/55°C (ambient)
without supplemental cooling.
If your high current requirements have made the use of inefficient linear regula-
tors impractical, take a look at one of Murata Power Solutions’ new switching buck
regulators. Their high efficiency, ease-of-use, long-term reliability, and overall cost
effectiveness will impress you. Safety agency approvals and EMC characterizations
are currently in progress.
3.0-3.6V input range; Non-isolated
1.5V, 1.8V or 2.5V output @ 10A
2" x 1" through-hole or SMT package
Gull-wing leads for SMT package
Full synchronous-rectifier topology
300kHz switching; Planar magnetics
High efficiency, to 89%
Low noise, 80mVp-p
Quick transient response, 25µsec
V
OUT
user-trimmable from 1.28V to 3V
–40 to +50/55°C ambient operation with
no derating
Remote on/off control; Output
overcurrent detection
IEC950/EN60950/UL1950 pending
EMC compliant
■
■
+V
IN
+V
OUT
INPUT
RETURN
OUTPUT
RETURN
LOGIC
GROUND
VOLTAGE
BOOST
+V
CC
OVERCURRENT
DETECTION
ON/OFF
CONTROL
PWM
CONTROLLER
REFERENCE &
ERROR AMP
V
OUT
TRIM
Figure 1. Simplified Schematic
Typical topology is shown.
For full details go to
www.murata-ps.com/rohs
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MDC_UNR15-25W.C01
Page 1 of 8
UNR D3 SERIES
Performance Specifications and Ordering Guide
➀
Output
Root Model
➅
UNR-1.5/10-D3T
UNR-1.5/10-D3SM
UNR-1.8/10-D3T
UNR-1.8/10-D3SM
UNR-2.5/10-D3T
UNR-2.5/10-D3SM
Single Output, Non-Isolated, 3.3V
IN
to 1.5/1.8/2.5V
OUT
8 and 10 Amp DC/DC Converters
Input
Regulation (Max.)
Line
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
V
OUT
(Volts)
1.5
1.5
1.8
1.8
2.5
2.5
I
OUT
(Amps)
10
10
10
10
10
10
R/N (mVp-p)
➁
Typ.
80
80
80
80
80
80
Max.
125
125
125
125
125
125
Load
➂
±0.5%
±0.5%
±0.5%
±0.5%
±0.5%
±0.5%
V
IN
Nom.
(Volts)
3.3
3.3
3.3
3.3
3.3
3.3
Range
➄
(Volts)
3.0-3.6
3.0-3.6
3.0-3.6
3.0-3.6
3.0-3.6
3.0-3.6
I
IN
➃
(mA/A)
375/5.74
375/5.74
275/6.38
275/6.38
370/8.51
370/8.51
Efficiency
Min.
80%
80%
82.5%
83%
85%
85%
Typ.
83.5%
83.5%
85.5%
85.5%
89%
89%
Package
(Case,
Pinout)
C16A2, P23
C18, P25
C16A2, P23
C18, P25
C16A2, P23
C18, P25
➀
Typical at T
A
= +25°C under nominal line voltage and full-load conditions, unless otherwise
noted. All models are tested and specified with an external 470µF input capacitor with a 20mΩ
ESR and a 6Arms ripple-current rating, as well as a 22µF output capacitor with a 200mΩ ESR.
See I/O Filtering and Noise Reduction for more details.
➁
Ripple/Noise (R/N) is tested/specified over a 20MHz bandwidth. Output noise may be further
reduced by installing additional external output caps. See I/O Filtering and Noise Reduction.
MECHANICAL SPECIFICATIONS
2.00
(50.80)
METAL CASE
0.39
(9.91)
INSULATED BASE
➂
These devices have no minimum-load requirements and will regulate under no-load conditions.
➃
Nominal line voltage, no-load/full-load conditions.
➄
The lowest input voltage for startup under full load is 3.1V minimum. Once started, the input voltage
may decay to 3.0V. Lighter loads will allow 3.0V startup.
➅
These are only partial model numbers. Refer to the part number structure when ordering.
0.100
(2.54)
4
3
0.500
(12.70)
2
0.300
(7.62)
1
TOP VIEW
9
0.110
(2.79)
Case C18
Pinout P25
8
7
6
5
0.800
(20.32)
4 EQ. SP. @
0.200 (5.08)
1.00
(25.40)
0.20 MIN
(5.08)
PINS 1-2, 4: 0.040 ±0.002
(1.016 ±0.051)
PINS 3, 5-7: 0.062 ±0.002
(1.575 ±0.051)
1.800
(45.72)
1
2
3
4
0.10
(2.54)
0.10
(2.54)
2.00
(50.80)
0.110
(2.79)
0.060
(1.52)
0.015
(0.38)
0.300
(7.62)
Case C16A2
Pinout P23
5
6
7
0.800
(20.32)
4 EQ. SP. @
0.200 (5.08)
1.00
(25.40)
0.43
(10.92)
INSULATED BASE
BOTTOM VIEW
DIMENSIONS IN INCHES (MM)
0.10
(2.54)
METAL CASE
DIMENSIONS ARE IN INCHES (MM)
0.015
(0.38)
0.055
(1.40)
I/O Connections
Pin
1
2
3
4
5
6
7
8
9
Function P23
Logic Ground
On/Off Control
+Output
Trim
Output Return
Input Return
+Input
No Pin
No Pin
Function P25
Logic Ground
On/Off Control
N.C.
N.C.
+Output
Trim
Output Return
Input Return
+Input
TEMPERATURE DERATING
28
24
UNR-2.5/10-D3
Output Power (Watts)
20
PART NUMBER STRUCTURE
UNR-1.8/10-D3
16
UNR-1.5/10-D3
12
U NR
-
1.8
/
10
-
D3 SM
-
C
Output Configuration:
U
= Unipolar
RoHS-6 compliant*
Packaging:
T
= Through-Hole Package
SM
= Surface-Mount Package
Input Voltage Range:
D3
= 3.0 to 3.6 Volts (3.3V nominal)
8
Non-Isolated
4
Nominal Output Voltage:
1.5, 1.8 or 2.5 Volts
0
40
45
50
55
60
65
70
75
80
85
90
95
100
0
–40
Maximum Rated Output
Current in Amps
* Contact Murata Power Solutions Technologies (DATEL) for availability.
Ambient Temperature (
˚
C)
See Temperature Derating section in Technical Notes for more details
.
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MDC_UNR15-25W.C01
Page 2 of 8
UNR D3 SERIES
Single Output, Non-Isolated, 3.3V
IN
to 1.5/1.8/2.5V
OUT
8 and 10 Amp DC/DC Converters
Performance/Functional Specifications
Typical @ T
A
= +25°C under nominal line voltage and full-load conditions unless noted.
➀
➀
All models are tested and specified with an external 470µF input capacitor with a 20mΩ
ESR and a 6Arms ripple-current rating, as well as a 22µF output capacitor with a 200mΩ ESR.
See I/O Filtering and Noise Reduction for more details. These devices have no minimum-load
requirements and will regulate under no-load conditions. Listed specifications apply for both
"T" and "SM" models as appropriate.
➁
See Output Overcurrent Detection for details.
➂
See On/Off Control for details.
➃
See Output Voltage Trimming for details.
➄
For all models, output noise can be further reduced with the installation of additional
external output capacitors. See I/O Filtering and Noise Reduction for details.
➅
Output overcurrent detection initiates at approximately 40% above rated load (14 Amps). Under
overload or short-circuit conditions, output current "hiccups" at approximately 1 Amp average
and remains at that level until the overload is removed. See Output Overcurrent Detection.
➆
See Start-Up Time for details.
➇
See Temperature Derating for details.
➈
The lowest input voltage for startup under full load is 3.1V minimum. Once started, the input
voltage may decay to 3.0V. Lighter loads will allow 3.0V startup
Input
Input Voltage Range
Input Current:
Normal Operating Conditions
Standby/Off Mode
Output Short Circuited
➁ ➅
Input Ripple Current:
UNR-1.5/10-D3, UNR-1.8/10-D3
UNR-2.5/10-D3
Input Filter Type
Overvoltage Protection
Reverse-Polarity Protection
On/Off Control
➂
3.0 to 3.6 Volts (3.3V nominal)
➈
See Ordering Guide
3.6mA typical, 8mA maximum
500mA typical, 700mA maximum
150mAp-p
50mAp-p
Capacitive
None
None
On = open or 2V to +V
IN
; I
IN
= 800µA max.
Off = 0-0.8V; I
IN
= 1.2mA max.
Absolute Maximum Ratings
Input Voltage:
Continuous
Transient (100msec)
Input Reverse-Polarity Protection
Input/Output Overvoltage Protection
Output Current
Output
V
OUT
Accuracy
(50% load):
UNR-1.5/10-D3
UNR-1.8/10-D3
UNR-2.5/10-D3
V
OUT
Trim Range
➃
Trim pin tied to +Output:
UNR-1.5/10-D3, UNR-1.8/10-D3
UNR-2.5/10-D3
Trim pin tied to Output Return
Temperature Coefficient
Ripple/Noise
(20MHz BW)
➄
Line/Load Regulation
Efficiency
Overcurrent Protection:
➅
Technique
Overcurrent Detection Point
Average Output Current
Transient Response
(50%-75% step)
Start-Up Time:
➆
V
IN
to V
OUT
On/Off to V
OUT
Switching Frequency
Operating Temperature
(Ambient):
➇
Without Derating
With Derating
Storage Temperature
Dimensions:
Through-Hole Models
Surface-Mount Models
Shielding
Case Connection
Case Material
±1% (±15mV) maximum
±1% (±18mV) maximum
±1% (±25mV) maximum
5 Volts
6.3 Volts
None
None
Current limited. Devices can
withstand a sustained output
short circuit without damage.
–40 to +105°C
+300°C
V
OUT
= 1.28 Volts or less
V
OUT
= 1.52 Volts or less
V
OUT
= 3.0 Volts or greater
±0.02% per °C
See Ordering Guide
See Ordering Guide
See Ordering Guide
"Hiccup" with auto-recovery
140% of rated current
1 Amp typical, 3 Amps maximum
25µsec to ±2.5% of final value
25/30msec (1.8/2.5V
OUT
models)
25/30msec (1.8/2.5V
OUT
models)
300kHz (±30kHz)
Storage Temperature
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.
TECHNICAL NOTES
Dynamic Characteristics
Environmental
–40 to +50/55°C
to +100°C (See Derating Curves)
–40 to +105°C
Return Current Paths
These are non-isolated DC/DC converters. The Input Return, Output Return
and Logic Ground pins are all connected together internally. To the extent
possible, all input and load currents should be returned through the Input
Return and Output Return, respectively (via low-impedance runs). Any con-
trol signals applied to the On/Off Control pin should be referenced to Logic
Ground. The internal trace leading to Logic Ground is not designed to carry
high current. Consequently, devices should never be installed in a manner
that results in high current flow through Logic Ground (i.e., the Input/Output
Return pins should never be left open or connected via high-impedance paths).
I/O Filtering and Noise Reduction
Physical
2" x 1" x 0.39" (51 x 25 x 9.9mm)
2" x 1" x 0.43" (51 x 25 x 10.9mm)
5 sided
Input/Output Return
Corrosion-resistant steel with
non-conductive, epoxy-based, black
enamel finish and plastic baseplate
RoHS: Gold-plate over copper alloy
Non-RoHS: Pure tin on copper alloy with
nickel underplate
1.4 ounces (39.7 grams)
All UNR 15-25W Series converters are tested and specified with external
470µF input capacitors (20mΩ ESR, 6Arms ripple-current rating) and
external 22µF output capacitors (200mΩ ESR). External input capacitance is
required and must be rated to handle the input ripple current as follows:
I
RMS
= I
OUT
√
V
OUT
V
IN
(
1 – V
OUT
)
V
IN
Pin Material
In critical applications, input/output ripple/noise may be further reduced by
installing additional I/O caps.
Weight
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MDC_UNR15-25W.C01
Page 3 of 8
UNR D3 SERIES
External input capacitors serve primarily as energy-storage elements. They
should be selected for bulk capacitance (at appropriate frequencies), low
ESR, and high rms-ripple-current ratings. The switching nature of modern
DC/DC converters requires that dc input voltage sources have low ac imped-
ance, and highly inductive source impedances can affect system stability.
Your specific system configuration may necessitate additional considerations.
Output ripple/noise (also referred to as periodic and random deviations or
PARD) can be reduced below specified limits using filtering techniques, the
simplest of which is the installation of additional external output capacitors.
Output capacitors function as true filter elements and should be selected for
bulk capacitance, low ESR, and appropriate frequency response. Any scope
measurements of PARD should be made directly at the DC/DC output pins
with scope probe ground less than 0.5" in length.
All external capacitors should have appropriate voltage ratings and be
located as close to the converters as possible. Temperature variations for all
relevant parameters should be taken into consideration.
The most effective combination of external I/O capacitors will be a function
of your line voltage and source impedance, as well as your particular load
and layout conditions. Our Applications Engineers can recommend potential
solutions and discuss the possibility of our modifying a given device’s internal
filtering to meet your specific requirements. Contact our Applications Engi-
neering Group for additional details.
Input Fusing
UNR 15-25W D3 Series DC/DC converters are not internally fused. Certain
applications and or safety agencies may require the installation of fuses at
the inputs of power conversion components. For Murata Power Solutions
UNR D3 Series DC/DC converters, you should use either slow-blow or
normal-blow fuses with values no greater than the following.
Output Voltage
1.5V Models
1.8V Models
2.5V Models
Fuse Value
11 Amps
12 Amps
18 Amps
Single Output, Non-Isolated, 3.3V
IN
to 1.5/1.8/2.5V
OUT
8 and 10 Amp DC/DC Converters
+INPUT
1kΩ
ON/OFF
CONTROL
LOGIC
GROUND
Figure 2. Driving the On/Off Control Pin
Applying an external voltage to the On/Off Control pin when no input power
is applied to the converter can cause permanent damage to the converter.
The on/off control function, however, is designed such that the converter
can be disabled (control pin pulled low) while input power (system 3.3V
power) is ramping up and then "released" once the input has stabilized.
The time duration between the point at which the converter is released and
its fully loaded output settles to within specified accuracy can be found in
the Performance/Functional Specifications Table. See Start-Up Time for more
details.
Start-Up Time
The V
IN
to V
OUT
Start-Up Time is the interval between the time at which a
ramping input voltage crosses the lower limit of the specified input voltage
range (3.0 Volts) and the fully loaded output voltage enters and remains within
it specified accuracy band. Actual measured times will vary with input source
impedance, external input capacitance, and the slew rate and final value of
the input voltage as it appears to the converter.
The On/Off to V
OUT
Start-Up Time assumes the converter is turned off via
the Remote On/Off Control with the nominal input voltage already applied to
the converter. The specification defines the interval between the time at which
the converter is turned on and the fully loaded output voltage enters and
remains within its specified accuracy band. See Typical Performance Curves
for details
Output Overvoltage Protection
UNR D3 Series DC/DC converters do not incorporate output overvoltage
protection. In the extremely rare situation in which the device’s feedback loop
is broken, the output voltage may run to excessively high levels (V
OUT
= V
IN
).
If it is absolutely imperative that you protect your load against any and all
possible overvoltage situations, voltage limiting circuitry must be provided
external to the power converter.
Output Overcurrent Detection
Overloading the output of a power converter for an extended period of
time will invariably cause internal component temperatures to exceed their
maximum ratings and eventually lead to component failure. High-current-
carrying components such as inductors, FET's and diodes are at the highest
risk. UNR D3 Series DC/DC converters incorporate an output overcurrent
detection and shutdown function that serves to protect both the power
converter and its load.
Input Overvoltage and Reverse-Polarity Protection
UNR D3 Series DC/DC converters do not incorporate either input overvoltage
or input reverse-polarity protection. Input voltages in excess of the listed
absolute maximum ratings and input polarity reversals of longer than "instan-
taneous" duration can cause permanent damage to these devices.
On/Off Control
The On/Off Control pin may be used for remote on/off operation. UNR D3
Series DC/DC converters are designed so that they are enabled when the
control pin is pulled high or left open (normal mode) and disabled when the
control pin is pulled low (to less than +0.8V relative to Logic Ground). As
shown in Figure 2, both 2.5V
OUT
and 1.8V
OUT
models have internal 1kΩ pull-
up resistors to V
IN
(+Input).
Dynamic control of the on/off function is best accomplished with a mechani-
cal relay or open-collector/open-drain drive circuit. The drive circuit should
be able to sink appropriate current when activated and withstand appropriate
voltage when deactivated.
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MDC_UNR15-25W.C01
Page 4 of 8
UNR D3 SERIES
When the output current of a thermally stabilized converter exceeds the
maximum rating (10A) by 40% (typical) to 80% (maximum), the internal over-
current detection circuit automatically shuts down the converter by discharg-
ing the soft-start circuit of the pulse width modulator (PWM). In this off state,
which is similar to that achieved by pulling the On/Off Control low, the output
voltage quickly drops as the output capacitors discharge into the load. Since
there is no longer any output current, the overcurrent detection circuit is
released, allowing the soft-start circuit to recharge and the converter to turn
on again. If the faulty load condition persists, the overcurrent detection circuit
will again discharge the soft-start circuit and shut down the converter. This
continuous on/off cycling of the converter is referred to as “hiccup mode.”
Once the overload condition is removed, the converter remains on, and the
output voltage is quickly restored to its regulated value.
The components used to sense the output current have large temperature
coefficients. Consequently, in a “cold-start” situation, the Overcurrent Detec-
tion Point may temporarily move to 80% to 120% above the rated current
specification. The device quickly heats up, particularly if an overload situation
exists, and restores the normal (40%) Overcurrent Detection Point. The
device easily survives starting up into an output-short-circuit condition.
The overcurrent detection circuitry helps keep internal current levels and
operating temperatures within safe operating limits. Nevertheless, sustained
operation at current levels above the rated output current (10 Amps) but
below the Overcurrent Detection Point (typically 14 Amps) may result in
permanent damage to the converter (unless active cooling keeps internal
temperatures below safe limits).
Output Voltage Trimming
For 2.5V
OUT
devices, the output can be trimmed to any voltage between
1.52V and 3.0V. For 1.5V
OUT
and 1.8V
OUT
devices, the output can be trimmed
to any voltage between 1.28V and 3.0V. Trimming is accomplished with either
a trimpot or a single fixed resistor. The trimpot should be connected between
+Output and Output Return with its wiper connected to the Trim pin as shown
in Figure 3 below.
Single Output, Non-Isolated, 3.3V
IN
to 1.5/1.8/2.5V
OUT
8 and 10 Amp DC/DC Converters
+OUTPUT
+INPUT
TRIM
INPUT
RETURN
Trim Up
OUTPUT
RETURN
Trim
Down
LOAD
Note:
Install either a fixed trim-up resistor or a fixed trim-down resistor
depending upon desired output voltage.
Figure 4. Trim Connections Using Fixed Resistors
Trim-Resistor Equations for 2.5V
OUT
Devices
V
OUT
= V
OUT
Desired
Trim Down
R
TRIM
(Ohms) =
7500 (V
OUT
–1.267)
2.5 – V
OUT
9465
V
OUT
– 2.5
–1740
–1740
Trim Up
R
TRIM
(Ohms) =
Trim-Resistor Equations for 1.8V
OUT
Devices
V
OUT
= V
OUT
Desired
Trim Down
R
TRIM
(Ohms) =
2670 (V
OUT
–1.267)
1.8 – V
OUT
3380
V
OUT
– 1.8
Trim Up
R
TRIM
(Ohms) =
Trim-Resistor Look-Up Table for Common Output Voltages
Desired Output
Voltage (Volts)
1.28
1.52
1.8
2
2.5
2.8
3
1.8V
OUT
Models
Trim Resistor (Ω)
Connect To
0
+Output
2.07k
+Output
Open
Open
16.9k
–Output
4.83k
–Output
3.38k
–Output
2.82k
–Output
2.5V
OUT
Models
Trim Resistor (Ω)
Connect To
N.A.
N.A.
0
+Output
4.03k
+Output
9.35k
+Output
Open
Open
29.7k
–Output
17.15k
–Output
+OUTPUT
+INPUT
TRIM
INPUT
RETURN
20kΩ
5-10
Turns
LOAD
OUTPUT
RETURN
Temperature Derating
Figure 3. Trim Connections Using a Trimpot
A trimpot can be used to determine the value of a single fixed resistor
which should be connected, as shown in Figure 4, between the Trim pin and
+Output to trim down the output voltage, or between the Trim pin and Output
Return to trim up the output voltage. Fixed resistors should be metal-film
types with absolute TCR’s less than 100ppm/°C to ensure stability.
The equations and look-up table below can be used as starting points for
selecting specific trim-resistor values. Recall that untrimmed devices are
guaranteed to be
±1%
accurate.
The outstanding electrical efficiency of the UNR D3 Series' synchronous-
rectifier design and the excellent thermal conductivity of its encapsulated
metal package combine to eliminate the need for heat sinking or supplemen-
tal forced-air cooling in the majority of routine applications. As shown in
the derating curves on page 2, 2.5V
OUT
models deliver full rated output
power (25 Watts) up to +55°C (ambient) and then derate linearly to +100°C.
1.8V
OUT
models deliver full rated output power (18 Watts) up to +50°C
(ambient) and similarly derate linearly to +100°C.
When operated with 3.0V input voltages, all devices in the UNR D3 Series
are more efficient and can operate to +60°C and +55°C, respectively. At
3.6V
IN
, devices operate less efficiently, and maximum full-load ambient
temperatures are reduced to +45°C and +50°C, respectively.
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MDC_UNR15-25W.C01
Page 5 of 8
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