Buck Regulator Electrical Characteristics

Buck1&2 have a current rating of I

(Buck1)

= Vnom1 , V

type apply over the full junction temperature range (−40˚C

≤ T

J

≤ +125˚C). Unless otherwise noted, specifications apply to the

LP3905 Typical Application Circuit (Figure. 1) (Notes 2, 8)

Symbol

Parameter

Condition

Min

Typ

Max

Units

V

FB

Feedback Voltage

(Note 16)

-4

+4

%

V

OUT

Line Regulation

3.0V

≤ V

IN

≤ 5.5V

I

0.045

%/V

Load Regulation

100 mA

≤ I

O

≤ 600mA

0.002

%/mA

R

DSON (P)

Pin-Pin Resistance for PFET

V

380

500

m

Ω

R

DSON (N)

Pin-Pin Resistance for NFET

V

250

400

m

Ω

I

LIM

Switch Peak Current Limit

Open Loop

650

1000

1220

mA

F

OSC

Internal Oscillator Frequency

PWM Mode

2

MHz

η

Efficiency

IOUT = 5mA, PFM mode (Note 15)

88

%

IOUT = 300mA, PWM mode (Note 15)

90

LDO Regulator Electrical Characteristics

The linear regulators have a current rating of I

Unless otherwise specified, limits are set with V

standard typeface are for T

≤ T

J

≤

+125˚C). Unless otherwise noted, specifications apply to the LP3905 Typical Application Circuit (Figure. 1)(Notes 2, 8)

Symbol

Parameter

Conditions

Min

Typ

Max

Units

∆V

OUT

Output Voltage Tolerance

Over Full Line and Load Regulation

−3

3

%

Line Regulation Error

V

I

0.05

%/V

Load Regulation Error

I

0.003

%/mA

I

LOAD

Load Current

(Notes 11, 15)

0

mA

V

DO

Dropout Voltage

I

80

150

mV

I

SC

Short Circuit Current Limit

(Note 13)

300

500

mA

I

OUT

Maximum Output Current

C

150

mA

PSRR

Power Supply Rejection Ratio

(Note 15)

f = 100Hz, I

90

dB

f = 1kHz, I

90

f = 10kHz, I

60

f = 50kHz, I

35

f = 100kHz, I

25

e

n

Output Noise Voltage

(Note 15)

BW = 10Hz to

100kHz, V

Buck1 Turned ON

with I

Buck2 Turned OFF

I

13.5

µV

RMS

I

15.5

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