LEN D12 Models
N O N - I S O L A T E D , 2 8 A E I G H T H B R I C K , D C / D C C O N V E R T E R S
Input
Input Voltage Range
10.2-13.8 Volts (12V nominal)
Input Current:
Normal Operating Conditions
See Ordering Guide
Inrush Transient
TBD
Standby/Off Mode
3.5mA
Output Short-Circuit Condition
130mA
Input Reected Ripple Current
20mAp-p
Input Filter Type
Capacitive (66F)
Overvoltage Protection
14.3 Volts
Reverse-Polarity Protection
None
Undervoltage Shutdown
9.4 Volts
On/Off Control
On = open or 0 to +0.4V
Off = +2.8V to +VIN (<3mA)
Output
VOUT Accuracy (50% load)
±1.5% maximum
Minimum Loading
No load
Maximum Capacitive Load
10,000F (low ESR, OSCON)
VOUT Trim Range
±10% for VOUT =
≥1.8V
+10%/–3% for VOUT 1.5V and lower
(no trim for 0.8V models)
Ripple/Noise (20MHz BW)
See Ordering Guide
Total Accuracy
3% over line/load temperature
Efciency
See Ordering Guide
Overcurrent Detection and Short-Circuit Protection:
Current-Limiting Detection Point
35 Amps
Short-Circuit Detection Point
98% of VOUT set
SC Protection Technique
Hiccup with auto recovery
Short-Circuit Current
TBD
Dynamic Characteristics
Transient Response (25% load step)
100sec to ±2% of nal value
Start-Up Time:
VIN to VOUT and On/Off to VOUT
20ms
Switching Frequency
320kHz ±40kHz
Environmental
Calculated MTBF
TBD million hours
Operating Temperature: (Ambient)
Without Derating (With 200 lfm)
–40 to +65°C (model dependent)
With Derating
See Derating Curves
Thermal Shutdown
+125°C
Physical
Dimensions
See Mechanical Dimensions
Pin Material
Copper, solder coated over nickel underplate
Weight
0.6 ounces (17g)
Flamability Rating
UL94V-0
Performance/Functional Specications
Typical @ TA = +25°C under nominal line voltage and full-load conditions unless noted.
All models are tested and specied with external 33F tantalum input and output capacitors.
These capacitors are necessary to accommodate our test equipment and may not be
required to achieve specied performance in your applications. All models are stable and
regulate within spec under no-load conditions.
Input Ripple Current is tested/specied over a 5-20MHz bandwidth with an external 33F
input capacitor and a simulated source impedance of 220F and 12H. See I/O Filtering,
Input Ripple Current and Output Noise for details.
The On/Off Control (pin 4) is designed to be driven with open-collector logic or the appli-
cation of appropriate voltages (referenced to Common, pins 1, 6 and 8).
Output noise may be further reduced with the installation of additional external output
ltering. See I/O Filtering and Noise Reduction.
MTBF’s are calculated using Telcordia SR-332(Bellcore), ground xed, TA = +25°C, full
power, natural convection, TBD pcb temperature.
See Performance Specications, note 6.
T E C H N I C A L
N O T E S
Input Voltage:
Continuous or transient
15.5 Volts
On/Off Control (Pin 11)
+VIN
Input Reverse-Polarity Protection
None
Output Overvoltage Protection
VOUT +20%
Output Current
Current limited. Devices can
withstand sustained output short
circuits without damage.
Storage Temperature
–55 to +125°C
Lead Temperature (soldering, 10 sec.)
+300°C
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 Specications Table is not implied.
Absolute Maximum Ratings
Return Current Paths
The LEN D12 are non-isolated DC/DC converters. Their Common pins (pins
1, 6 and 8) 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 1 (also referred to as –Input or
Input Return), and output return current should be directed through pin 6
and 8 (also referred to as –Output or Output Return). Any on/off control
signals applied to pin 4 (On/Off Control) should be referenced to Common
(specically pin 1).
I/O Filtering and Noise Reduction
All models in the LEN D12 Series are tested and specied with external
33F tantalum input and output capacitors. These capacitors are necessary
to accommodate our test equipment and may not be required to achieve
desired performance in your application. The LEN D12's are designed with
high-quality, high-performance internal I/O caps, and will operate within spec
in most applications with no additional external components.
In particular, the LEN D12's input capacitors are specied for low ESR
and are fully rated to handle the units' input ripple currents. Similarly, the
internal output capacitors are specied for low ESR and full-range frequency
response. As shown in the Performance Curves, removal of the external
33F tantalum output caps has minimal effect on output noise.
In critical applications, input/output ripple/noise may be further reduced using
ltering techniques, the simplest being the installation of external I/O caps.
External input capacitors serve primarily as energy-storage devices. They
minimize high-frequency variations in input voltage (usually caused by IR
drops in conductors leading to the DC/DC) as the switching converter draws
pulses of current. Input capacitors should be selected for bulk capacitance (at
appropriate frequencies), low ESR, and high rms-ripple-current ratings. The
switching nature of modern DC/DC's requires that the dc input voltage source
have low ac impedance and the frequencies of interest. Highly inductive
source impedances can greatly affect system stability.Your specic system
conguration may necessitate additional considerations.
Output ripple/noise (also referred to as periodic and random deviations
or PARD) may be reduced below specied limits with the installation of
additional external output capacitors. Output capacitors function as true lter
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