®
®
PRELIMINARY
INNOVATION and EXCELLENCE
Single Output
USN D3 Models
Non-Isolated, 3.3V
IN
, 1.2-2.5V
OUT
8/10A DC/DC’s in SIP Packages
Features
■
■
■
■
■
Industry-standard SIP pinout
Shorter (2.0" vs. 2.5") package length
3.0-3.6V input range
1.2/1.5/1.8/2.5V outputs @ 8 or 10 Amps
Non-isolated, fully synchronous,
200kHz, buck topology
Outstanding performance:
•
±1% setpoint accuracy
•
Efficiencies to 92%
•
Noise as low as 25mVp-p
•
Stable no-load operation
•
Wide-range trimmable output voltage
Remote on/off control; Optional sense pin
Power-good pin and "Lucent-compatible"
on/off control available
EN60950 and UL1950 certified
EMC compliant
■
■
■
■
■
DATEL’s new USN D3 Series SIP’s (single-in-line packages) are non-isolated
DC/DC converters that accept a 3.3V input (3.0V to 3.6V input range) and deliver 1.2,
1.5V, 1.8V or 2.5V outputs at either 8 or 10 Amps. USN D3 SIP’s are designed to take
on-board 3.3V power and convert it, with the highest efficiency in the smallest space, to
any lower voltage required by today’s current-hungry DSP’s, ASIC’s and CPLD’s.
USN’s are ideal for true point-of-use power processing. They occupy a mere
0.8 square inches of board space (2" length, 0.4" width, 0.53" height). Their fully
synchronous, fixed-frequency (200kHz), buck topology delivers high efficiency (92%
for 2.5V
OUT
models), tight regulation (±0.1%/±0.625% line/load), stable no-load
operation, and low output noise.
The fully functional USN’s feature input undervoltage shutdown, output overcur-
rent detection, continuous short-circuit protection, a wide-range output-voltage trim
function, a remote on/off control pin (available in either positive or negative logic),
and an optional sense pin. High efficiency allows the USN D3's to deliver rated output
currents at an ambient temperature of +45°C for 10 Amp models and +50°C for
8 Amp models with 100lfm air flow.
If your low-voltage, high-current requirements have made the use of inefficient
linear regulators impractical, take a look at one of DATEL’s easy-to-use, low-cost
USN SIP’s. All devices are UL1950/EN60950 certified and EMC compliant. UL, CB
and EMC reports are available upon request.
+INPUT
+OUTPUT
+SENSE
➀
(OPTIONAL)
COMMON
COMMON
VOLTAGE
BOOST
CURRENT
SENSE
V
CC
ON/OFF
CONTROL
PWM
CONTROLLER
REFERENCE &
ERROR AMP
TRIM
➀
For devices with the sense-pin option ("R" suffix), the
feedback path is through the +Sense pin and not the
+Output pin.
Figure 1. Simplified Schematic
DATEL, Inc., Mansfield, MA 02048 (USA) · Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 · Email: sales@datel.com · Internet: www.datel.com
USN Series
N O N - I S O L AT E D , 1 0 - 2 5 W S I P D C / D C C O N V E R T E R S
Performance Specifications and Ordering Guide
Output
➀
Input
Regulation (Max.)
Line
Load
➂
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.625%
±0.625%
±0.625%
±0.625%
±0.625%
±0.625%
±0.5%
±0.5%
PRELIMINARY
Model
USN-1.2/8-D3
USN-1.2/10-D3
USN-1.5/8-D3
USN-1.5/10-D3
USN-1.8/8-D3
USN-1.8/10-D3
USN-2.5/8-D3
USN-2.5/10-D3
V
OUT
(Volts)
1.2
1.2
1.5
1.5
1.8
1.8
2.5
2.5
I
OUT
(Amps)
8
10
8
10
8
10
8
10
R/N (mVp-p)
➁
Typ.
Max.
TBD
TBD
25
25
25
25
30
30
TBD
TBD
50
50
50
50
60
60
V
IN
Nom.
(Volts)
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
Range
(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
3.0-3.6
3.0-3.6
I
IN
➃
(mA)
TBD/3547
TBD/4381
TBD/4300
TBD/5320
TBD/5100
TBD/6230
TBD/6730
TBD/8230
Efficiency
Min.
Typ.
TBD
TBD
81.5%
81.5%
81.5%
81.5%
87%
87%
82%
83%
84.5%
85.5%
85.5%
87.5%
90%
92%
Package
(Case,
Pinout)
B4, P50
B4, P50
B4, P50
B4, P50
B4, P50
B4, P50
B4, P50
B4, P50
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 220µF input capacitor with a
100mΩ ESR and a 1.28Arms ripple-current rating, as well as a 220µF output capacitor with a
100mΩ ESR. See I/O Filtering and Noise Reduction for details.
➁
Ripple/Noise (R/N) is tested/specified over a 20MHz bandwidth. See I/O Filtering and
Noise Reduction.
➂
These devices have no minimum load requirements and will regulate under no-load conditions.
➃
Nominal line voltage, no-load/full-load conditions.
P A R T
N U M B E R
S T R U C T U R E
T E M P E R AT U R E D E R AT I N G
U SN
-
1.8
/
10
-
D3 R
9
Temperature Derating for 8 Amp Models
V
IN
= Nominal
Output Configuration:
U
= Unipolar
Non-Isolated SIP
Nominal Output Voltage:
1.2, 1.5, 1.8, or 2.5 Volts
Maximum Rated Output
Current in Amps
8
Output Current (Amps)
R Suffix:
Remote Sense
(Pin 3 installed)
Input Voltage Range:
D3
= 3.0 to 3.6 Volts (3.3V nominal)
7
6
5
4
3
2
Still Air
100lfm Air Flow
200lfm Air Flow
300lfm Air Flow
PRELIMINARY
M E C H A N I C A L
S P E C I F I C A T I O N S
1
2.00
(50.80)
0.40
(10.16)
0.24
(6.10)
0
–40 0
5
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Ambient Temperature (
˚
C)
0.180
(4.57)
Case B4
1 2 3 4 5
6 7 8 9 10 11
0.53
(13.46)
0.025
(0.64)
0.05
(1.27)
0.05
(1.27)
12
Temperature Derating for 10 Amp Models
V
IN
= Nominal
PRELIMINARY
10
Output Current (Amps)
0.400
(10.16)
4 EQ. SP. @
0.100 (2.54)
1.000
(25.40)
0.500
(12.70)
5 EQ. SP. @
0.100 (2.54)
0.160
(4.06)
8
DIMENSIONS ARE IN INCHES (MM)
* See Functional Options
in Technical Notes.
** Pin 3 (+Sense) installed
for "R" suffix models.
I/O Connections
Pin Function P50*
1
+Output
2
+Output
3
No Pin**
4
+Output
5
Common
6
Common
7
+Input
8
+Input
9
No Pin*
10
Trim
11
On/Off Control
6
4
Still Air
100lfm Air Flow
200lfm Air Flow
2
300lfm Air Flow
0
–40 0
5
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Ambient Temperature (
˚
C)
2
N O N - I S O L AT E D , 1 0 - 2 5 W S I P D C / D C C O N V E R T E R S
USN Models
Performance/Functional Specifications
Typical @ T
A
= +25°C under nominal line voltage and full-load conditions unless noted.
➀
Input
Input Voltage Range
Input Current:
Normal Operating Conditions
Standby/Off Mode
Input Ripple Current
Input Filter Type
Overvoltage Protection
Reverse-Polarity Protection
Undervoltage Shutdown
On/Off Control
➁ ➂
D3 Models
D3 "N" Models
3.0 to 3.6 Volts (3.3V nominal)
See Ordering Guide
TBD
TBD
Capacitive (66µF)
None
None
TBD
➀
All models are tested and specified with an external 220µF input capacitor with a 100mΩ
ESR and a 1.28Arms ripple-current rating, as well as a 220µF output capacitor with a
100mΩ ESR rating.
➁
See Technical Notes/Graphs for details.
➂
The On/Off Control is designed to be driven with open-collector logic or the application of
appropriate voltages (referenced to Common, pins 5 and 6). Applying a voltage to the
On/Off Control pin (pin 11) when no input voltage is applied to the converter may cause
permanent damage. See Functional Options for "N" models.
➃
All models are stable and regulate within spec under no-load conditions.
➄
Output noise may be further reduced with the installation of additional external output
capacitors. See I/O Filtering and Noise Reduction.
➅
If an output short circuit results in a latched shutdown, the converter will have to be re-
started by cycling either the input voltage or the On/Off Control pin.
Absolute Maximum Ratings
On = open or 2.4V to +V
IN
, I
IN
max. <400µA
Off = 0-0.8V, I
IN
max. <600µA
Off = open or 2.5V to +V
IN
, I
IN
max. =3.3mA
On = 0-0.8V, I
IN
max. <1mA
Input Voltage:
Continuous
Transient (100msec)
On/Off Control
(Pin 11)
Input Reverse-Polarity Protection
Output Overvoltage Protection
Output Current
7 Volts
8 Volts
+V
IN
None
None
Current limited. Devices can
withstand sustained output short
circuits without damage.
–40 to +105°C
+300°C
Output
V
OUT
Accuracy
(50% load)
Minimum Loading
➃
V
OUT
Trim Range
➁
Ripple/Noise
(20MHz BW)
➄
Line/Load Regulation
Efficiency
➁
Overcurrent Detection and
Short-Circuit Protection:
➁ ➅
Current-Limiting Detection Point:
8 Amp Models
10 Amp Models
Short-Circuit Detection Point
SC Protection Technique
Transient Response
(50% load step)
Start-Up Time:
➁
V
IN
to V
OUT
On/Off to V
OUT
Switching Frequency
MTBF:
Bellcore, ground fixed,
full power, 100lfm air flow
8A Outputs (+50°C air)
10A Outputs (+45°C air)
Operating Temperature:
➁
(Ambient, 100lfm air flow)
Without Derating 8A/10A
With Derating
Storage Temperature
Dimensions
Package
Pin Dimensions/Material
Weight
Flamability Rating
±1% maximum
No load
+10%, –15%
See Ordering Guide
See Ordering Guide
See Ordering Guide
Storage Temperature
Lead Temperature
(soldering, 10 sec.)
TBD
TBD
<80% of rated output voltage
Latched shutdown
50µsec to ±1.5% of final value
TBD
TBD
200kHz (±28kHz)
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.
T E C H N I C A L
N O T E S
Dynamic Characteristics
Return Current Paths
The USN 10-25W D3 SIP’s are non-isolated DC/DC converters. Their two
Common pins (pins 5 and 6) are connected to each other internally (see
Figure 1). To the extent possible (with the intent of minimizing ground loops),
input return current should be directed through pin 6 (also referred to –Input
or Input Return), and output return current should be directed through
pin 5 (also referred to as –Output or Output Return). Any on/off control
signals applied to pin 11 (On/Off Control) should be referenced to Common
(specifically pin 6).
I/O Filtering and Noise Reduction
Environmental
6 million hours
7 million hours
–40 to +45/50°C
to +100°C (See Derating Curves)
–40 to +105°C
Physical
2" x 0.40" x 0.53" (50.8 x 10.2 x 13.5mm)
Open-frame, single-in-line (SIP)
0.025" (0.635mm) square bronze with
tin-lead plate over nickel underplate
0.3 ounces (8.5gm)
UL94V-0
All models in the USN 10-25W D3 Series are tested and specified with an
external 220µF input capacitor (100mΩ ESR, 1.28Arms ripple-current
rating) and an external 220µF (100mΩ ESR) output capacitor. In critical
applications, input/output ripple/noise may be further reduced by installing
additional, external I/O caps.
External input capacitors serve primarily as energy-storage devices to mini-
mize variations in input voltage caused by transient IR drops in conductors
leading to the input of the DC/DC. They should be selected for bulk capaci-
tance (at appropriate frequencies), low ESR, and high rms-ripple-current
ratings. The switching nature of modern DC/DC converters requires that the
dc input voltage source have low ac impedance, and highly inductive source
impedances can affect system stability. Your specific system configuration
may necessitate additional considerations.
3
USN Series
N O N - I S O L AT E D , 1 0 - 2 5 W S I P D C / D C C O N V E R T E R S
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
USN 10-25W D3 SIP 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 DATEL USN D3
SIP converters, you should use either slow-blow or normal-blow fuses with
values no greater than the following.
Model
USN-1.2/8-D3
USN-1.2/10-D3
USN-1.5/8-D3
USN-1.5/10-D3
USN-1.8/8-D3
USN-1.8/10-D3
USN-2.5/8-D3
USN-2.5/10-D3
Fuse Value
TBD
TBD
9 Amps
11 Amps
11 Amps
13 Amps
14 Amps
17 Amps
+INPUT
10kΩ
ON/OFF
CONTROL
COMMON
Figure 2. Driving the Positive-Logic 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 dura-
tion 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.
The "N" suffix models (negative-logic models) can be driven using a circuit
comparable to that shown in Figure 3. Leaving the On/Off control pin open
or applying a voltage between 2.5V and +V
IN
will turn off the converter.
Applied voltages to the On/Off Control pin between 0V to +0.8V will enable
the converter.
Contact DATEL for information on "N" models.
+INPUT
2kΩ
ON/OFF
CONTROL
665Ω
Input Overvoltage and Reverse-Polarity Protection
USN D3 SIP Series DC/DC converters do not incorporate either input
overvoltage or input reverse-polarity protection. Input voltages in excess
of the specified absolute maximum ratings and input polarity reversals of
longer than "instantaneous" duration can cause permanent damage to these
devices.
On/Off Control
The On/Off Control pin may be used for remote on/off operation. USN D3 SIP
Series (positive logic models) are designed so that they are enabled when
the control pin is pulled high (+2.4V to +V
IN
applied) or left open (normal
mode) and disabled when the control pin is pulled low (to less than +0.8V
relative to Common). As shown in Figures 2 and 3, all models have internal
10kΩ pull-up resistors to +5V.
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.
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 its 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
COMMON
Figure 3. Driving the "Negative Logic" On/Off Control Pin
Start-Up Time
4
N O N - I S O L AT E D , 1 0 - 2 5 W S I P D C / D C C O N V E R T E R S
USN Models
Output Overvoltage Protection
USN D3 SIP 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. USN D3 SIP Series DC/DC converters incorporate an output overcur-
rent detection and shutdown function that serves to protect both the power
converter and its load.
When the output current exceeds its maximum rating by 20% (typical) to 35%
(maximum), the internal overcurrent-detection circuit limits output current.
If the overload condition forces V
OUT
to fall below 80% of its rated value,
the short-circuit detection circuit will latch the DC/DC into an off state. The
latched condition can be reset by cycling the input voltage to the converter or
by cycling the On/Off Control pin.
Output Voltage Trimming
Allowable trim ranges for each model in the USN D3 SIP Series are +10%,
–15%. Trimming is accomplished with either a trimpot or a single fixed resis-
tor. The trimpot should be connected between +Output and Common with its
wiper connected to the Trim pin as shown in Figure 4 below.
+OUTPUT
+INPUT
TRIM
COMMON
COMMON
Trim Up
Trim
Down
LOAD
Note:
Install either a fixed trim-up resistor or a fixed trim-down resistor
depending upon desired output voltage.
Figure 5. Trim Connections Using Fixed Resistors
USN-1.8/8-D3, USN-1.8/10-D3 Trim Equations
R
T
DOWN
(kΩ) =
2.55(V
O
– 1.23)
1.8 – V
O
3.14
V
O
– 1.8
– 2.21
R
T
UP
(kΩ) =
– 2.21
USN-2.5/8-D3, USN-2.5/10-D3 Trim Equations
R
T
DOWN
(kΩ) =
5.677(V
O
– 1.23)
2.5 – V
O
6.98
V
O
– 2.5
– 4.42
R
T
UP
(kΩ) =
– 4.42
+OUTPUT
+INPUT
TRIM
COMMON
COMMON
20kΩ
5-10
Turns
LOAD
Note: Resistor values are in kΩ. Accuracy of adjustment is subject to
tolerances of resistors and factory-adjusted, initial output accuracy.
V
O
= desired output voltage.
Functional Options
USN Series D3 SIP’s have been thoughtfully designed to incorporate a
number of functional options that are not routinely offered as part-number
suffixes. These options are readily available to customers who desire them,
however, you must contact DATEL to discuss availability.
In particular, the On/Off Control function can be configured with a "negative"
polarity. For standard products, the device is operational when the On/Off
Control pin (pin 11) is left open or pulled high. For "N" devices, the opposite
is true. Devices are off when is pin 11 is left open, and they become
operational only when pin 11 is pulled low.
Similarly, a "power-good" function (that can be "polled" in applications requir-
ing digital monitoring of system power functions) can be added in the pin 9
position which is empty on standard products.
Contact DATEL directly to discuss either of these options or any other
modifications you may want us to make to USN D3 Series SIP’s.
Figure 4. Trim Connections Using a Trimpot
A trimpot can be used to determine the value of a single fixed resistor
which can then be connected, as shown in Figure 5, between the Trim pin
and +Output to trim down the output voltage, or between the Trim pin and
Common to trim up the output voltage. Fixed resistors should have absolute
TCR’s less than 100ppm/°C to ensure stability.
The equations below can be used as starting points for selecting specific
trim-resistor values. Recall that untrimmed devices are guaranteed to be
±1%
accurate.
Adjustment beyond the specified +10%, –15% adjustment range is not
recommended.
5
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