LM10502

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SNVS884B – AUGUST 2012 – REVISED MAY 2013

Buck 2 Electrical Characteristics

(1) (2) (3)

Unless otherwise noted, VIN = 5.0V where: VIN=VVIN_B1 = VVIN_B2. L1 = 2.2µH,C3=C5=22µF,C2=C4=4.7µF.

The application circuit used is the one shown in "Typical Application Circuit."

Limits in standard typeface are for TJ = 25°C.

Limits appearing in boldface type apply over the entire operating junction temperature range of

−30°C ≤ TA = TJ ≤ +85°C.

Symbol

Parameter

Conditions

Min

Typ

Max

Units

IQ

DC Bias Current in VIN

No Load, PFM Mode

15

50

µA

Continuous load current((4)

IOUT-MAX

Buck 1 enabled switching in PWM

1.0

(5) (6) (7))

IPEAK

Peak switching current limit

Buck 1 enabled, switching in PWM

1.3

1.575

1.85

A

η

Efficiency peak, Buck 2(5)

IOUT = 0.3A,VIN = 5.0V

90

%

FSW

Switching Frequency

1.75

2

2.3

MHz

CIN

Input Capacitor(5)

4.7

µF

Output Filter Capacitor(5)

10

22

100

COUT

0mA

≤ IOUT ≤ -IOUT-MAX

Output Capacitor ESR(5)

20

m

Ω

L

Output Filter Inductance(5)

2.2

µH

VFB

Feedback Voltage

VOUT = 1.2V (Default) PWM Mode,No Load

-3

3

%

DC Line regulation(5)

3.3V

≤ VIN ≤ 5.0V, IOUT = IOUT-MAX

0.5

%/V

ΔVOUT

DC Load regulation(5)

100 mA

≤ IOUT ≤ IOUT-MAX

0.3

%/A

Feedback pin input bias

IFB

VFB = 1.2V

1.6

4

µA

current

VIN = 5.0V

140

High Side Switch On

RDS-ON-HS

Resistance

VIN = 2.6V

220

m

Ω

Low Side Switch On

RDS-ON-LS

VIN = 5.0V

70

150

Resistance

STARTUP

Startup from shutdown, VOUT = 0V, no load, LC =

Internal soft-start (turn on

TSTART

recommended circuit, using software enable, to

0.1

ms

time)(5)

VOUT = 95% of final value

(1)

All limits are ensured by design, test and/or statistical analysis. All electrical characteristics having room-temperature limits are tested

during production with TJ = 25°C. All hot and cold limits are ensured by correlating the electrical characteristics to process and

temperature variations and applying statistical process control.

(2)

Capacitors: Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) are used in setting electrical characteristics.

(3)

BUCK normal operation is ensured if VIN ≥ VOUT+1.0V.

(4)

Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which

operation of the device is ensured. Operating Ratings do not imply ensured performance limits. For ensured performance limits and

associated test conditions, see the General Electrical Characteristics.

(5)

Specification ensured by design. Not tested during production.

(6)

In applications where high power dissipation and/or poor 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).

(7)

The amount of Absolute Maximum power dissipation allowed for the device depends on the ambient temperature and can be calculated

using the formula: P = (TJ–TA)/θJA, where TJ is the junction temperature, TA is the ambient temperature, and θJA is the junction-to-

ambient thermal resistance.

θJA is highly application and board-layout dependent. Internal thermal shutdown circuitry protects the device

from permanent damage. (See General Electrical Characteristics.)

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