LP2952IM National Semiconductor, LP2952IM Datasheet - Page 12

• Manufacturer Part Number: LP2952IM
• Description: IC ADJ LDO REG 1.23V TO 29V 250mA 16-SOIC
• Manufacturer: National Semiconductor

Specifications of LP2952IM

• Primary Input Voltage: 30V
• Output Voltage Adjustable Range: 1.23V To 29V
• Dropout Voltage Vdo: 470mV
• No. Of Pins: 16
• Output Current: 250mA
• Operating Temperature Range: -40°C To +125°C
• Dc: 05+
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Schematic Diagram
Application Hints
HEATSINK REQUIREMENTS (Industrial Temperature
Range Devices)
The maximum allowable power dissipation for the LP2952/
LP2953 is limited by the maximum junction temperature
(+125˚C) and the external factors that determine how quickly
heat flows away from the part: the ambient temperature and
the junction-to-ambient thermal resistance for the specific
application.
The industrial temperature range (−40˚C ≤ T
parts are manufactured in plastic DIP and surface mount
packages which contain a copper lead frame that allows
heat to be effectively conducted away from the die, through
J
≤ +125˚C)
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the ground pins of the IC, and into the copper of the PC
board. Details on heatsinking using PC board copper are
covered later.
To determine if a heatsink is required, the maximum power
dissipated by the regulator, P(max), must be calculated. It is
important to remember that if the regulator is powered from
a transformer connected to the AC line, the maximum
specified AC input voltage must be used (since this pro-
duces the maximum DC input voltage to the regulator).
Figure 1 shows the voltages and currents which are present
in the circuit. The formula for calculating the power dissi-
pated in the regulator is also shown in Figure 1:
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