LP5951

VIN

OUT

GND

NC

IN

Enable Control,

active high

1

3

2

4

5

Load

EN

1 2F

1 2F

LP5951

SNVS345G – JUNE 2006 – REVISED DECEMBER 2014

www.ti.com

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LP5951 is a linear voltage regulator for digital applications designed to be stable with space-saving ceramic

capacitors as small as 1 µF. Performance is specified for a -40°C to 125°C temperature range for bot the SOT-

23 and SC70 packages.

8.2 Typical Application

Figure 10. LP5951 Typical Application

8.2.1 Design Requirements

Table 1. Design Parameters

DESIGN PARAMETER

DESIGN REQUIREMENT

Input voltage range

1.8 V to 5.5 V

Output voltage

1.3 V

Output current

150 mA

Output capacitor range

1 µF

Input/output capacitor ESR range

3 m

Ω to 300 mΩ

8.2.2 Detailed Design Procedure

8.2.2.1 Power Dissipation And Device Operation

The permissible power dissipation for any package is a measure of the capability of the device to pass heat from

the power source, the junctions of the IC, to the ultimate heat sink, the ambient environment. Thus, the power

dissipation is dependent on the ambient temperature and the thermal resistance across the various interfaces

between the die and ambient air.

In applications where high power dissipation and/or poor package thermal resistance is present, the maximum

ambient temperature may have to be derated. Maximum ambient temperature (TA-MAX) is dependent on the

maximum operating junction temperature (TJ-MAX-OP = 125°C), the maximum power dissipation of the device in

the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application

(RθJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (RθJA × PD-MAX).

The allowable power dissipation for the device in a given package can be calculated using the equation:

PD = (TJ(MAX) – TA) /RθJA

(1)

With an RθJA = 195.6°C/W, the device in the SOT-23-5 package returns a value of 511 mW with a maximum

junction temperature of 125°C at TA of 25°C.

10

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