SC338AIMSTRT Semtech, SC338AIMSTRT Datasheet - Page 7

• Manufacturer Part Number: SC338AIMSTRT
• Description: IC FET CONTROLLER DUAL 10-MSOP
• Manufacturer: Semtech
• Type: Positive Adjustabler

Specifications of SC338AIMSTRT

• Number Of Outputs: 2
• Voltage - Output: 0.5 ~ 1.8 V, 0.5 ~ 3.3 V
• Current - Supply: 500µA
• Voltage - Input: 5V, 12V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: SC338AIMSTR

supplied to the MOSFET drain should be greater than
the output undervoltage threshold when that
output is enabled. This assumes that the drop through
the pass MOSFET is negligible. If not, then this drop needs
to be taken into account also since:
V
If the supply to the SC338(A) IN pin comes up before the
supply to the MOSFET drain, then that output should be
enabled as the supply to the MOSFET drain is applied
- the Power Good signal for this rail would be ideal. If the
power supply to the MOSFET drain comes up before the
power supply to the SC338(A) IN pin, then the output
can either be enabled with the supply to the IN pin or
afterwards. Please see the example below.
Example: SC338(A) powered from 5V, output 1 powered
POWER MANAGEMENT
Applications Infomation (Cont.)
OUT
2004 Semtech Corp.
= V
DRAIN
- (I
OUT
x R
DS(ON)
).
SC338(A) Supply Comes Up Before MOSFET Drain Supply
MOSFET Drain Supply Comes Up Before SC338(A) Supply
Figure 1: Power Supply Sequencing
7
from 1.8V set for 1.5V out, output 2 not shown for
simplicity. Worst case undervoltage threshold is 60% (over
temperature) of 1.5V, or 0.9V. The typical enable
threshold is ~1V. See Figure 1 below.
Component Selection
Output Capacitors: low ESR capacitors such as Sanyo
POSCAPs or Panasonic SP-caps are recommended for
bulk capacitance, with ceramic bypass capacitors for
decoupling high frequency transients.
Input Capacitors: placement of low ESR capacitors such
as Sanyo POSCAPs or Panasonic SP-caps at the input to
the MOSFET (V
during fast load changes, thus improving overall transient
response. If V
the upstream voltage regulator, additional capacitance
DRAIN
DRAIN
) will help to hold up the power supply
is located at the bulk capacitors for
SC338(A)
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