LP5952TLX-1.0 - Texas Instruments High-Performance Analog

LP5952

LP5952 350mA Dual Rail Linear Regulator

Literature Number: SNVS469D

June 10, 2008

LP5952

350mA Dual Rail Linear Regulator

General Description

The LP5952 is a Dual Supply Rail Linear Regulator optimized

for powering ultra-low voltage circuits from a single Li-Ion cell

or 3 cell NiMH/NiCd batteries.

In the typical post regulation application VBATT is directly con-

nected to the battery (range 2.5V...5.5V) and VIN is supplied

by the output voltage of the DC-DC Converter (range 0.7V...

4.5V).

The device offers superior dropout and transient features

combined with very low quiescent currents. In shutdown

mode (Enable pin pulled low) the device turns off and reduces

battery consumption to 0.1µA (typ.).

The LP5952 also features internal protection against over-

temperature, over-current and under-voltage conditions.

Performance is specified for a -40°C to 125°C junction tem-

perature range.

The device is available in a tiny 5-bump micro SMD and a 6-

pin Chip On Lead LLP package, lead free.

The device is available in fixed output voltages in the range

of 0.5V to 2.0V. For availability, please contact your local NSC

sales office.

Features

■Excellent load transient response: ±15mV typical

■Excellent line transient response: ±1mV typical

■0.7V ≤ VIN ≤ 4.5V

■2.5V ≤ VBATT ≤ 5.5V

■0.5V ≤ VOUT ≤ 2.0V

■For ILOAD = 350mA:

VBATT ≥ VOUT(NOM) + 1.5V or 2.5V whichever is higher

■For ILOAD = 150mA:

VBATT ≥ VOUT(NOM) + 1.3V or 2.5V whichever is higher

■50µA typical quiescent current from VBATT

■10µA typical quiescent current from VIN

■0.1µA typical quiescent current in shutdown

■Guaranteed 350mA output current

■Noise voltage = 100µVRMS typical

■Operates from a single Li-Ion cell or 3 cell NiMH/NiCd

batteries

■Only one or two tiny surface-mount external components

required depending on application

■Small, thin 5-bump micro SMD package and 6-pin Chip On

Lead LLP package, lead free

■Thermal-overload and short-circuit protection

■-40°C to +125°C junction temperature range

Applications

■Mobile Phones

■Hand-Held Radios

■Personal Digital Assistants

■Palm-Top PCs

■Portable Instruments

■Battery Powered Devices

Typical Application Circuit

20208501

FIGURE 1. Typical Application Circuit with DC-DC Converter as Pre-Regulator for VIN

LP5952 350mA Dual Rail Linear Regulator

20208502

FIGURE 2. Typical Application Circuit

Connection Diagrams

5-Bump Micro SMD Package

20208503

Connection Diagram 5-Bump Thin Micro SMD Package, Large Bump, 0.5mm Pitch

See NS Package Number TLA05

Package Marking

20208506

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LP5952

LLP-6 Package

20208524

Connection Diagram 6-Pin Chip On Lead LLP package, 0.5mm pitch

See NS Package Number LCA06B

Note: The actual physical placement of the package marking will vary from part to part. The package marking “X” designates the

date code. “T” is a NSC internal code for die traceability. Both will vary considerably. “U” identifies the device (part number, option,

etc.).

Pin Descriptions

Pin Number

Micro SMD

Pin Number

LLP

Pin Name Description

A1 3 VIN Power input voltage; input range: 0.7V to 4.5V, VIN ≤ VBATT

A3 4 VOUT Regulated output voltage

B2 2 GND Ground

C1 1 VBATT Bias input voltage; input range: 2.5V to 5.5V

C3 6 EN Enable pin logic input: low = shutdown, high = active, normal operation.

This pin should not be left floating. Tie to VBATT if this function is not used.

5 NC Do not make connections to this pin

Order Information (5-bump micro SMD)

Output Voltage

(V)

LP5952 Supplied as 250 Units,

Tape and Reel, lead free

LP5952 Supplied as 3000 Units,

Tape and Reel, lead free Flow Package

Marking

0.7 LP5952TL-0.7 LP5952TLX-0.7 NOPB 4

1.0 LP5952TL-1.0 LP5952TLX-1.0 NOPB L

1.2 LP5952TL-1.2 LP5952TLX-1.2 NOPB 7

1.3 LP5952TL-1.3 LP5952TLX-1.3 NOPB U

1.4 LP5952TL-1.4 LP5952TLX-1.4 NOPB A

1.5 LP5952TL-1.5 LP5952TLX-1.5 NOPB T

1.6 LP5952TL-1.6 LP5952TLX-1.6 NOPB B

1.8 LP5952TL-1.8 LP5952TLX-1.8 NOPB 8

2.0 LP5952TL-2.0 LP5952TLX-2.0 NOPB 5

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LP5952

Order Information (COL LLP-6)

Output Voltage

(V)

LP5952 Supplied as 1000 Units,

Tape and Reel, lead free

LP5952 Supplied as 4500 Units,

Tape and Reel, lead free

Flow Package

Marking

1.2 LP5952LC-1.2 LP5952LCX-1.2 NOPB L28

1.3 LP5952LC-1.3 LP5952LCX-1.3 NOPB L43

1.5 LP5952LC-1.5 LP5952LCX-1.5 NOPB L25

1.8 LP5952LC-1.8 LP5952LCX-1.8 NOPB L29

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LP5952

Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

VIN, VBATT pins: Voltage to GND,

VIN ≤ VBATT:-0.2V to 6.0V

VBATT pin to VIN pin: 0.2V

EN pin, Voltage to GND: -0.2V to 6.0V

Continuous Power Dissipation

(Note 3): Internally Limited

Junction Temperature (TJ-MAX ): 150°C

Storage Temperature Range: -65°C to + 150°C

Package Peak Reflow Temperature

(Pb-free, 10-20 sec.) (Note 4): 260°C

ESD Rating (Note 5):

Human Body Model: 2.0kV

Machine Model: 200V

Operating Ratings

Input Voltage Range VIN 0.7V to 4.5V

Input Voltage Range VBATT 2.5V to 5.5V

VEN Input Voltage 0 to VBATT

Recommended Load Current 0mA to 350mA

Junction Temperature (TJ) Range -40°C to + 125°C

Ambient Temperature (TA) Range

(Note 6) -40°C to + 85°C

Thermal Properties

Junction-to-Ambient Thermal

Resistance (θJA)

TLA05 package (Note 7) 95°C/W

LCA06B package (Note 7) 150°C/W

ESD Caution Notice

National Semiconductor recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper

ESD handling techniques can result in damage.

Electrical Characteristics (Notes 2, 8, 11)

Typical values and limits appearing in standard typeface are for TA = 25°C. Limits appearing in boldface type apply over the full

operating temperature range: -40°C ≤ TJ ≤ +125°C. Unless otherwise noted, specifications apply to the typical application circuit

with VIN = VOUT(NOM) + 1.0V, VBATT = VOUT(NOM) + 1.5V or 2.5V, whichever is higher, IOUT = 1mA, CVIN = 1.0µF, COUT = 2.2µF,

VEN = VBATT.

Symbol Parameter Condition Typ Limit Units

Min Max

ΔVOUT / VOUT Output Voltage Tolerance VIN = VOUT(NOM) + 0.3V -1.5

-2.0

1.5

2.0

ΔVOUT / ΔVIN Line Regulation Error

VIN = VOUT(NOM) + 0.3V to 4.5V, VBATT =

4.5V

0.3 1.0 mV/V

ΔVOUT / ΔVBATT VBATT = VOUT(NOM) + 1.5V (≥ 2.5V) to 5.5V 0.5 2.2

ΔVOUT / ΔmA Load Regulation Error

IOUT = 1mA to 350mA, micro SMD

package 15 30 µV/mA

IOUT = 1mA to 350mA, LLP-6 package 43 60 µV/mA

ISC

Output Current

(short circuit)

VOUT = 0V, VEN = VIN = VBATT = VOUT

(NOM) + 1.5V 500 350 mA

VDO_VBATT

(Note 10)

Output Voltage Dropout VBATT

(Note 9)

IOUT = 350mA, VIN = VOUT(NOM) + 0.3V,

micro SMD package 1.07 1.5 V

IOUT = 350mA, VIN = VOUT(NOM) + 0.3V,

LLP-6 package 1.08 1.5 V

IOUT = 150mA, VIN = VOUT(NOM) + 0.3V,

micro SMD package 0.96 1.3 V

IOUT = 150mA, VIN = VOUT(NOM) + 0.3V,

LLP-6 package 0.97 1.3 V

VDO_VIN Output Voltage Dropout VIN

IOUT = 350mA, VBATT = VOUT(NOM) + 1.5V

or 2.5V, micro SMD package 88 200 mV

IOUT = 350mA, VBATT = VOUT(NOM) + 1.5V

or 2.5V, LLP-6 package 128 250 mV

ENOutput Noise 10Hz to 100kHz 100 µVRMS

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LP5952

Symbol Parameter Condition Typ Limit Units

Min Max

PSRR Power Supply Rejection Ratio

Sine modulated VBATT

f = 10Hz

f = 100Hz

f = 1kHz

Sine modulated VIN

f = 10Hz

f = 100Hz

f = 1kHz

f = 10kHz

f = 100kHz

Quiescent Currents

Symbol Parameter Condition Typ Limit Units

Min Max

IQ_VBATT Current into VBATT ILOAD = 0...350mA 50 100 µA

IQ_VIN Current into VIN ILOAD = 0 11 28 µA

Shutdown Currents

Symbol Parameter Condition Typ Limit Units

Min Max

IQ_VBATT Current into VBATT VEN = 0V 0.1 1µA

IQ_VIN Current into VIN VEN = 0V 0.1 1µA

Enable Control Characteristics

Symbol Parameter Conditions Typ Limit Units

Min Max

IEN

Maximum Input Current at VEN

Input

0.01 1µA

VIL Low Input Threshold (shutdown) 0.4 V

VIH High Input Threshold (enable) 1.0 V

Thermal Protection

Symbol Parameter Conditions Typ Limit Units

Min Max

TSHDN Thermal-Shutdown Temperature 165 °C

ΔTSHDN Thermal-Shutdown Hysteresis 20 °C

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LP5952

Transient Characteristics

Symbol Parameter Conditions Typ Limit Units

Min Max

ΔVOUT

Dynamic Line Transient

Response VIN

VIN = VOUT(NOM) + 0.3V to

VOUT(NOM) + 0.9V; tr, tf = 10µs ±1 mV

ΔVOUT

Dynamic Line Transient

Response VBATT

VBATT = VOUT(NOM) + 1.5V to

VOUT(NOM) + 2.1V; tr, tf = 10µs ±15 mV

ΔVOUT

Dynamic Load Transient

Response

Pulsed load 0 ...300mA, di/dt = 300mA/

1µs

micro SMD package

±15

Pulsed load 0 ...300mA, di/dt = 300mA/

1µs

LLP-6 package

-35/

+15

TSTARTUP Startup Time EN to 0.95 * VOUT 70 150 µs

Input and Output Capacitors, Recommended Specification

Symbol Parameter Conditions Nom Limit Units

Min Max

COUT Output Capacitance Capacitance (Note 12) 2.2 1.5 10 µF

ESR 3 300 mΩ

CVIN Input Capacitance at VIN

Capacitance (Note 12), not needed in typ

post regulation application,

see Figure 1

1 0.47

µF

ESR 3 300 mΩ

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation

of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions,

see the Electrical Characteristics tables.

Note 2: All voltages are with respect to the potential at the GND pin.

Note 3: Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ = 165°C (typ.) and disengages at TJ

= 145°C (typ.).

Note 4: For detailed soldering specifications and information, please refer to National Semiconductor Application Note 1112: Micro SMD Wafer Level Chip Scale

Package (AN-1112) and Application Note 1187: Leadless Leadframe Package (LLP) (AN-1187).

Note 5: The Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged

directly into each pin. (MIL-STD-883 3015.7)

Note 6: 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 (θJA), as given by the

following equation: TA-MAX = TJ-MAX-OP – (θJA × PD-MAX).

Note 7: Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power dissipation exists,

special attention must be paid to thermal dissipation issues in board design.

Note 8: Min and Max limits are guaranteed by design, test, or statistical analysis. Typical (Typ) numbers are not guaranteed, but do represent the most likely

norm. Unless otherwise specified, conditions for Typ specifications are: VIN = VOUT(NOM) + 1.0V, VBATT= VOUT(NOM) + 1.5V or 2.5V, whichever is higher, TA = 25°

Note 9: Dropout voltage is defined as the input to output voltage differential at which the output voltage falls to 100mV below the nominal output voltage.

Note 10: This specification does not apply if the battery voltage VBATT needs to be decreased below the minimum operating limit of 2.5V during this test.

Note 11: VOUT(NOM) is the stated output voltage option

Note 12: The capacitor tolerance should be 30% or better over temperature. The full operating conditions for the application should be considered when selecting

a suitable capacitor to ensure that the minimum value of capacitance is always met. Recommended capacitor type is X7R. However, dependent on application,

X5R, Y5V, and Z5U can also be used. The shown minimum limit represents real minimum capacitance, including all tolerances and must be maintained over

temperature and dc bias voltage (See capacitor section in Applications Hints)

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LP5952

Block Diagram

20208505

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LP5952

Typical Performance Characteristics Unless otherwise specified, CIN = 1.0µF ceramic, COUT = 2.2µF

ceramic, VIN = VOUT(NOM) + 1V, VBATT = VOUT(NOM) + 1.5V, TA = 25°C, Enable pin is tied to VBATT. Micro SMD package.

Load Transient Response, 0.7V Option

20208509

Load Transient Response, 1.5V Option

20208510

Line Transient Response VIN, 1.5V Option

20208511

Line Transient Response VBATT, 1.5V Option

20208512

Enable Start-up Time, 0.7V Option

20208513

Enable Start-up Time, 1.5V Option

20208514

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LP5952

Output Voltage Change vs Temperature

20208515

Dropout VIN vs Temperature, ILOAD = 350mA

20208516

Inrush Current VIN, 1.5V Option

20208517

Quiescent Current IQ_VBATT vs VBATT

20208522

Ground Current vs VBATT / VIN

20208519

Ground Current vs Load Current

20208523

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LP5952

Power Supply Rejection Ratio VIN, 1.5V Option

20208520

Power Supply Rejection Ratio VBATT, 1.5V Option

20208521

Application Hints

DUAL RAIL SUPPLY

The LP5952 requires two different supply voltages:

•VIN, the power input voltage, is regulated to the fixed output

voltage

•VBATT, the bias input voltage, supplies internal circuitry.

It's important that VIN does not exceed VBATT at any time. If

the device is used in the typical post regulation application as

shown in Figure 1, the sequencing of the two power supplies

is not an issue as VBATT supplies both, the DC-DC regulator

and the LP5952. The output voltage of the DC-DC regulator

will take some time to rise up and supply VIN of LP5952. In

this application VIN will always ramp up more slowly than

VBATT.

In case VIN is shorted to VBATT, the voltages at the two supply

pins will ramp up simultaneously causing no problem.

Only in applications with two independent supplies connected

to the LP5952 special care must be taken to guarantee that

VIN is always ≤ VBATT.

POWER DISSIPATION AND DEVICE OPERATION

The permissible power dissipation for any package is a mea-

sure 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 depen-

dent on the ambient temperature and the thermal resistance

across the various interfaces between the die and ambient

air.

As stated in the electrical specification section, the allowable

power dissipation for the device in a given package can be

calculated using the equation:

PD = (TJ(MAX) - TA) / θJA

With a θJA = 95°C/W, the device in the 5 bump micro SMD

package returns a value of 1053mW with a maximum junction

temperature of 125°C at TA of 25°C or 421mW at TA of 85°C.

The actual power dissipation across the device can be esti-

mated by the following equation:

PD = (VIN - VOUT) * IOUT

This establishes the relationship between the power dissipa-

tion allowed due to thermal consideration, the voltage drop

across the device, and the continuous current capability of the

device. These two equations should be used to determine the

optimum operating conditions for the device in the application.

As an example, to keep full load current capability of 350mA

for a 1.5V output voltage option at a high ambient temperature

of 85°C, VIN has to be kept ≤ 2.7V (for micro SMD package):

VIN ≤ PD / IOUT + VOUT = 421mW / 350mA + 1.5V = 2.7V.

Figure 3 shows the output current derating due to these con-

siderations:

20208525

FIGURE 3. Maximum Load Current vs VIN - VOUT, TA =

85°C, VOUT = 1.5V, θJA(MICROSMD) = 95°C/W,

θJA(LLP) = 150°C/W,

The typical contribution of the bias input voltage supply

VBATT to the power dissipation can be neglected:

PD_VBATT = VBATT * IQVBATT = 5.5V * 50µA = 0.275mW typical.

EXTERNAL CAPACITORS

As is common with most regulators, the LP5952 requires ex-

ternal capacitors to ensure stable operation. The LP5952 is

specifically designed for portable applications requiring mini-

mum board space and the smallest size components. These

capacitors must be correctly selected for good performance.

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LP5952

INPUT CAPACITOR

If the LP5952 is used stand alone, an input capacitor at VIN is

required for stability. It is recommended that a 1.0µF capacitor

be connected between the LP5952 power voltage input pin

VIN and ground (this capacitance value may be increased

without limit).

This capacitor must be located a distance of not more than 1

cm from the VIN pin and returned to a clean analogue ground.

Any good quality ceramic, tantalum, or film capacitor may be

used at the input.

A capacitor at VBATT is not required if the distance to the sup-

ply does not exceed 5cm.

If the device is used in the typical application as post regulator

after a DC-DC regulator, no input capacitors are required at

all as the capacitors of the DC-DC regulator (CIN and COUT)

are sufficient if both components are mounted close to each

other and a proper GND plane is used. If the distance between

the output capacitor of the DC-DC regulator and the VIN pin

of the LP5952 is larger than 5cm, it's recommended to add

the mentioned input capacitor at VIN.

Important: Tantalum capacitors can suffer catastrophic fail-

ures due to surge current when connected to a low-

impedance source of power (like a battery or a very large

capacitor). If a tantalum capacitor is used at the input, it must

be guaranteed by the manufacturer to have a surge current

rating sufficient for the application.

The ESR (Equivalent Series Resistance) of the input capac-

itor should be in the range of 3mΩ to 300mΩ. The tolerance

and temperature coefficient must be considered when select-

ing the capacitor to ensure the capacitance will remain ≥

470nF over the entire operating temperature range.

OUTPUT CAPACITOR

The LP5952 is designed specifically to work with very small

ceramic output capacitors. A ceramic capacitor (dielectric

types X7R, Z5U, or Y5V) in the 2.2µF range (up to 10µF) and

with an ESR between 3mΩ to 300mΩ is suitable as COUT in

the LP5952 application circuit.

This capacitor must be located a distance of not more than

1cm from the VOUT pin and returned to a clean analogue

ground.

It is also possible to use tantalum or film capacitors at the

device output, VOUT, but these are not as attractive for rea-

sons of size and cost (see the section Capacitor Character-

istics).

CAPACITOR CHARACTERISTICS

The LP5952 is designed to work with ceramic capacitors on

the output to take advantage of the benefits they offer. For

capacitance values in the range of 1µF to 4.7µF, ceramic ca-

pacitors are the smallest, least expensive and have the lowest

ESR values, thus making them best for eliminating high fre-

quency noise. The ESR of a typical 1µF ceramic capacitor is

in the range of 3mΩ to 40mΩ, which easily meets the ESR

requirement for stability for the LP5952.

For both input and output capacitors, careful interpretation of

the capacitor specification is required to ensure correct device

operation. The capacitor value can change greatly, depend-

ing on the operating conditions and capacitor type.

In particular, the output capacitor selection should take ac-

count of all the capacitor parameters, to ensure that the

specification is met within the application. The capacitance

can vary with DC bias conditions as well as temperature and

frequency of operation. Capacitor values will also show some

decrease over time due to aging. The capacitor parameters

are also dependant on the particular case size, with smaller

sizes giving poorer performance figures in general. The ex-

ample shows a typical graph comparing different capacitor

case sizes in a Capacitance vs. DC Bias plot. As shown in the

graph, increasing the DC Bias condition can result in the ca-

pacitance value falling below the minimum value given in the

recommended capacitor specifications table (0.47/1.5µF in

this case). Note that the graph shows the capacitance out of

spec for the 0402 case size capacitor at higher bias voltages.

It is therefore recommended that the capacitor manufactur-

ers’ specifications for the nominal value capacitor are con-

sulted for all conditions, as some capacitor sizes (e.g. 0402)

may not be suitable in the actual application.

20208507

FIGURE 4. Graph Showing A Typical Variation In

Capacitance vs DC Bias

The ceramic capacitor’s capacitance can vary with tempera-

ture. The capacitor type X7R, which operates over a temper-

ature range of -55°C to +125°C, will only vary the capacitance

to within ±15%. The capacitor type X5R has a similar toler-

ance over a reduced temperature range of -55°C to +85°C.

Many large value ceramic capacitors, larger than 1µF are

manufactured with Z5U or Y5V temperature characteristics.

Their capacitance can drop by more than 50% as the tem-

perature varies from 25°C to 85°C. Therefore X7R is recom-

mended over Z5U and Y5V in applications where the ambient

temperature will change significantly above or below 25°C.

Tantalum capacitors are less desirable than ceramic for use

as output capacitors because they are more expensive when

comparing equivalent capacitance and voltage ratings in the

1µF to 4.7µF range.

Another important consideration is that tantalum capacitors

have higher ESR values than equivalent size ceramics. This

means that while it may be possible to find a tantalum capac-

itor with an ESR value within the stable range, it would have

to be larger in capacitance (which means bigger and more

costly) than a ceramic capacitor with the same ESR value. It

should also be noted that the ESR of a typical tantalum will

increase about 2:1 as the temperature goes from 25°C down

to -40°C, so some guard band must be allowed.

NO-LOAD STABILITY

The LP5952 will remain stable and in regulation with no ex-

ternal load. This is an important consideration in some cir-

cuits, for example CMOS RAM keep-alive applications.

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LP5952

ENABLE OPERATION

The LP5952 may be switched ON or OFF by a logic input at

the Enable pin, VEN. A logic high at this pin will turn the device

on. When the enable pin is low, the regulator output is off and

the device typically consumes 0.1µA.

If the application does not require the Enable switching fea-

ture, the VEN pin should be tied to VBATT to keep the regulator

output permanently on.

To ensure proper operation, the signal source used to drive

the VEN input must be able to swing above and below the

specified turn-on/off voltage thresholds listed in the Electrical

Characteristics section under Enable Control Characteristics,

VIL and VIH.

FAST TURN ON

Fast turn-on is guaranteed by an optimized architecture al-

lowing a fast ramp of the output voltage to reach the target

voltage while the inrush current is controlled low at 120mA

typical (for a COUT of 2.2µF).

SHORT-CIRCUIT PROTECTION

The LP5952 is short circuit protected and in the event of a

peak over-current condition, the output current through the

NFET pass device will be limited.

If the over-current condition exists for a longer time, the av-

erage power dissipation will increase depending on the input

to output voltage difference until the thermal shutdown cir-

cuitry will turn off the NFET.

Please refer to the section on thermal information for power

dissipation calculations.

THERMAL-OVERLOAD PROTECTION

Thermal-Overload Protection limits the total power dissipation

in the LP5952. When the junction temperature exceeds TJ =

165°C typ., the shutdown logic is triggered and the NFET is

turned off, allowing the device to cool down. After the junction

temperature dropped by 20°C (temperature hysteresis) typi-

cal, the NFET is activated again. This results in a pulsed

output voltage during continuous thermal-overload condi-

tions.

The Thermal-Overload Protection is designed to protect the

LP5952 in the event of a fault condition. For normal, continu-

ous operation, do not exceed the absolute maximum junction

temperature rating of TJ = +150°C (see Absolute Maximum

Ratings).

REVERSE CURRENT PATH

The internal NFET pass device in LP5952 has an inherent

parasitic body diode. During normal operation, the input volt-

age is higher than the output voltage and the parasitic diode

is reverse biased. However, if the output is pulled above the

input in an application, then current flows from the output to

the input as the parasitic diode gets forward biased. The out-

put can be pulled above the input as long as the current in the

parasitic diode is limited to 50mA. For currents above this limit

an external Schottky diode must be connected from VOUT to

VIN (cathode on VIN, anode on VOUT).

EVALUATION BOARDS

For availability of evaluation boards please refer to the Prod-

uct Folder of LP5952 at www.national.com.

For information regarding evaluation boards, please refer to

Application Note: AN-1531.

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LP5952

Physical Dimensions inches (millimeters) unless otherwise noted

NS Package Number TLA05Z1A

X1 = 955 µm ±30µm

X2 = 1335µm ±30µm

X3 = 600µm ±75µm

5-Bump Thin Micro SMD Package, Large Bump

NS Package Number LCA06B

6-Pin Chip On Lead LLP Package, 0.5mm Pitch

For most accurate revision please refer to www.national.com/packaging/parts/

www.national.com 14

LP5952

Notes

15 www.national.com

LP5952

Notes

LP5952 350mA Dual Rail Linear Regulator

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