LSN2-T/30-D12-C Murata Power Solutions Inc, LSN2-T/30-D12-C Datasheet - Page 11

• Manufacturer Part Number: LSN2-T/30-D12-C
• Description: CONV DC/DC 150W 30A 0.8-5V SIP
• Manufacturer: Murata Power Solutions Inc
• Series: LSN2r
• Type: Point of Load (POL) Non-Isolatedr

Specifications of LSN2-T/30-D12-C

• Number Of Outputs: 1
• Output: 0.8 ~ 5V
• Power (watts): 150W
• Mounting Type: Through Hole
• Voltage - Input: 6 ~ 14V
• Package / Case: 13-SIP Module
• 1st Output: 0.8 ~ 5 VDC @ 30A
• Size / Dimension: 2.00" L x 0.45" W x 0.50" H (50.8mm x 11.4mm x 12.7mm)
• Power (watts) - Rated: 150W
• Operating Temperature: -40°C ~ 85°C
• Efficiency: 94%
• Approvals: CSA, EN, UL
• Output Power: 150 W
• Input Voltage Range: 6 V to 14 V
• Input Voltage (nominal): 12 V
• Output Voltage (channel 1): 0.8 V to 5 V
• Output Current (channel 1): 30 A
• Package / Case Size: SIP
• Output Type: Low Voltage Selectable
• Output Voltage: 0.8 V to 5 V
• Product: Non-Isolated / POL
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• 3rd Output: -
• 2nd Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 811-1806-5

different respective fi nal set point voltages. During the ramp, their voltages
are nearly identical. This avoids problems with large currents fl owing between
logic systems which are not initialized yet. Since both end voltages are differ-
ent, each converter reaches it’s setpoint voltage at a different time.
ing fi nal voltages at about the same time.
Operation
To use the Sequence pin after power start-up stabilizes, apply a rising external
voltage to the Sequence input. As the voltage rises, the output voltage will
track the Sequence input (gain = 1). The output voltage will stop rising when it
reaches the normal set point for the converter. The Sequence input may option-
ally continue to rise without any effect on the output. Keep the Sequence input
voltage below the converter’s input supply voltage.
until the Sequence input falls below the set point.
below show simple RC networks but you may also use operational amplifi ers,
D/A converters, etc.
Circuits
The circuits shown in Figures 5 through 13 introduce several concepts when
using these Sequencing controls on Point-of-Load (POL) converters. These
circuits are only for reference and are not intended as fi nal designs ready for
your application. Also, numerous connections are omitted for clarity.
the POL B ramps up identically to POL A as shown in timing diagram Figure 6.
RC network R1 and C1 charge up at a rate set by the R1-C1 time constant,
giving a roughly linear ramp. As POL A reaches 3.3V out (the setpoint of POL B),
POL B will stop rising. POL A then continues rising until it reaches 5V.
bias current resistor from the Sequence pin. Start with a value of 20 Kilohms.
In Figure 10, we assume that the critical phase is only on power up therefore
there is no provision for ramped power down.
added a small FET at Q1 to function as an up/down control. When V
fi rst applied to the POL, Q1 is biased on, shorting out the Sequence pin. When
Q1’s gate is biased off, R1 now charges C1 and the POL’s output now ramps up
at the R1-C1 slew rate. Note that Q1’s gate would typically be controlled from
some external digital logic.
small resistor in series with Q1’s drain.
In Figure 10, two POLs ramp up at the same rate until they reach their
Figure 12 shows two POLs with different slew rates in order to reach differ-
Use a similar strategy on power down. The output voltage will stay constant
Any strategy may be used to deliver the power up/down ramps. The circuits
Figure 10 shows a basic Master (POL A) and Slave (POL B) connected so that
R1 should be selected so that it is signifi cantly smaller than the internal
Figure 11 shows a single POL and the same RC network. However we have
If you wish to have a ramped power down (rather than a step down), add a
www.murata-ps.com
IN
power is
ing divider (R2 and R3) on POL B. We have also added an optional very small
noise fi lter cap at C2. Figure 12’s circuit corresponds roughly to Figure 7’s
timing for power up.
Guidelines for Sequence/Track Applications
[1] Leave the converter’s On/Off Enable control (if installed) in the On setting.
[2] Allow the converter to stabilize (typically less than 20 mS after +V
[3] If you do not plan to use the Sequence/Track pin, leave it open.
[4] Observe the Output slew rate relative to the Sequence input. A rough
[5] Be aware of the input characteristics of the Sequence pin. The high input
[6] Allow the converter to eventually achieve its full rated setpoint output volt-
[7] The Sequence is a sensitive input into the feedback control loop of the
[8] If one converter is slaving to another master converter, there will be a very
[9] You may connect two or more Sequence inputs in parallel from two con-
Figure 12 shows both a RC ramp on Master POL A and a proportional track-
Normally, you should just leave the On/Off pin open.
on) before raising the Sequence input. Also, if you wish to have a ramped
power down, leave +V
shut off power.
guide is 2 Volts per millisecond maximum slew rate. If you exceed this
slew rate on the Sequence pin, the converter will simply ramp up at
it’s maximum output slew rate (and will not necessarily track the faster
Sequence input). The reason to carefully consider the slew rate limitation
is in case you want two different POL’s to precisely track each other.
impedance affects the time constant of any small external ramp capacitor.
And the bias current will slowly charge up any external caps over time
if they are not grounded. The internal pull up resistor to +V
400 Kilohms to 1 Megohm.
Notice in the simplifi ed Sequence/Track equivalent circuit (Figure 13) that
a blocking diode effectively disconnects this circuit when the Sequence/
Track pin is left open.
age. Do not remain in ramp up/down mode indefi nitely. The converter is
characterized and meets all its specifi cations only at the setpoint voltage
(plus or minus any trim voltage). During the ramp-up phase, the converter
is not considered fully in regulation. This may affect performance with
excessive high current loads at turn-on.
converter. Avoid noise and long leads on this input. Keep all wiring very
short. Use shielding if necessary.
short phase lag between the two converters. This can usually be ignored.
verters. Be aware of the increasing pull-up bias current and reduced input
impedance.
25 Jun 2010 MDC_LSN2-T/30-D12
LSN2-T/30-D12 Series
DOSA-SIP, 30A POL DC/DC Converters
IN
powered all during the down ramp. Do not simply
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is typically
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power