LP38852EVAL National Semiconductor, LP38852EVAL Datasheet - Page 2

• Manufacturer Part Number: LP38852EVAL
• Description: BOARD EVALUATION LP38852
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LP38852EVAL

• Channels Per Ic: 1 - Single
• Voltage - Output: 1.2V
• Current - Output: 1.5A
• Voltage - Input: 3 ~ 5.5V
• Regulator Type: Positive Adjustable
• Operating Temperature: -40°C ~ 125°C
• Board Type: Fully Populated
• Utilized Ic / Part: LP38852
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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The Enable pin has a 200 kΩ internal resistor to V
Enable pin is left open, care should be taken to minimize any
capacitance on the Enable pin, as any capacitance will intro-
duce an RC delay time on the Enable function.
Soft-Start Function
V
of the SS pin (r
to the SS pin. This allows the output voltage to rise in a con-
trolled manner until steady-state regulation is achieved. Typ-
ically, five time constants are recommended to assure that the
output voltage is sufficiently close to the final steady-state
value. During the soft-start time the output current can rise to
the built-in current limit.
The LP38852MR-ADJ Evaluation board is assembled with a
0.01 μF capacitor for C
proximately 750 μs.
REF
will rise at an RC rate defined by the internal resistance
FIGURE 3. Enable Thresholds
SS
), and the external capacitor (C
FIGURE 4. V
SS
. This sets the soft-start time to ap-
OUT
Soft-Start
SS
30002405
30002404
) connected
BIAS
. If the
2
Power Dissipation
The LP38852MR PSOP-8 package alone has a junction to
ambient thermal resistance (θ
mounted on the LP38852MR evaluation board the θ
is approximately 62°C/W.
Although there is only approximately 0.03 square inches (0.1
x 0.3) 1 ounce copper area immediately under the DAP, the
top copper surface area is extended to additional copper area
on the bottom of the board by four thermal vias.
With the 62°C/W thermal rating the LP38852MR-ADJ evalu-
ation board will dissipate a maximum of 1.6W with T
FIGURE 5. Maximum Power Dissipation vs Ambient
Temperature
JA
) rating of 168°C/W. When
30002406
A
JA
= 25°C.
rating