LSN16A-D12 Datasheet, PDF (6/13 Pages) Murata Manufacturing Co., Ltd. – Single Output, Non-Isolated, 12VIN, 0.75-5VOUT 16 Amp in DC/DCs SIP Packages

LSN-16A D12 Models
Single Output, Non-Isolated, 12VIN, 0.75-5VOUT
16 Amp in DC/DCs SIP Packages
On/Off Control and Power-up Sequencing
The On/Off Control pin may be used for remote on/off operation. LSN D12 SIP
Series DC/DC's are designed so they are enabled when the control pin is left
open (internal pull-down to Common) and disabled when the control pin is
pulled high (+2.8V to +VIN), as shown in Figure 2 and 2a.
+INPUT
4.12k7
ON/OFF
CONTROL
15.4k7
POWER
COMMON
SHUTDOWN
SIGNAL
GROUND
CONTROLLER
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 com-
ponents such as inductors, FET's and diodes are at the highest risk. LSN D12
SIP Series DC/DC converters incorporate an output overcurrent detection and
shutdown function that serves to protect both the power converter and its load.
If the output current exceeds it maximum rating by typically 60% (24 Amps)
or if the output voltage drops to less than 98% of it original value, the LSN
D12's internal overcurrent-detection circuitry immediately turns off the con-
verter, which then goes into a "hiccup" mode. While hiccupping, the converter
will continuously attempt to restart itself, go into overcurrent, and then shut
down. Under these conditions, the average output current will be approximately
400mA, and the average input current will be approximately 40mA. Once the
output short is removed, the converter will automatically restart itself.
Figure 2. Driving the On/Off Control Pin with an
External Open-Collector Drive Circuit
+INPUT
CMOS
LOGIC
4.12k7
ON/OFF
CONTROL
15.4k7
POWER
COMMON
SHUTDOWN
SIGNAL
GROUND
CONTROLLER
Output Voltage Trimming
For all models except "T" versions. See "T" Trimming.
Allowable trim ranges for each model in the LSN D12 SIP Series are ±10%.
Trimming is accomplished with either a trimpot or a single fixed resistor. The
trimpot should be connected between +Output and Common with its wiper
connected to the Trim pin as shown in Figure 3 below.
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Figure 2A. Inverting On/Off Control Pin with an External CMOS Gate
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 on/off control function, however, can be externally inverted so that
the converter will be disabled while the input voltage is ramping up and then
"released" once the input has stabilized.
#/--/.
Figure 3. 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 4, 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/oC to ensure stability.
For a controlled start-up of one or more LSN-D12's, or if several output volt-
ages need to be powered-up in a given sequence, the On/Off Control pin can
be pulled high (external pull-up resistor, converter disabled) and then driven
low with an external open collector device to enable the converter.
Output Overvoltage Protection
LSN D12 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 (VOUT = VIN). 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.
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5P
Note:
Install either a fixed
trim-up resistor or a
fixed trim-down resis-
tor depending upon
desired output voltage.
Figure 4. Trim Connections Using Fixed Resistors
The equations below can be used as starting points for selecting specific trim-
resistor values. Recall, untrimmed devices are guaranteed to be ±1% accurate.
Adjustment beyond the specified ±10% adjustment range is not recommended.
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