LM3478

LM3478-Q1

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SNVS085V – JULY 2000 – REVISED FEBRUARY 2013

Electrical Characteristics

Symbol

Parameter

Conditions

Typical

Limit

Unit

Feedback Voltage

1.26

V

2.97

1.2416/1.228

V(min)

1.2843/1.292

V(max)

Feedback Voltage Line

2.97

0.001

%/V

Regulation

Output Voltage Load

±0.5

%/A (max)

Regulation

Input Undervoltage Lock-out

2.85

V

2.97

V(max)

Input Undervoltage Lock-out

170

mV

Hysteresis

130

mV (min)

210

mV (max)

Nominal Switching Frequency

400

kHz

350

kHz(min)

440

kHz(max)

Driver Switch On Resistance

16

Ω

(top)

Driver Switch On Resistance

4.5

Ω

(bottom)

Maximum Drive Voltage

V

7.2

100

%

Minimum On Time

325

nsec

210

nsec(min)

600

nsec(max)

Supply Current (non-switching)

(3)

2.7

mA

3.3

mA (max)

Quiescent Current in

5

µA

Shutdown Mode

10

µA (max)

Current Sense Threshold

156

mV

Voltage

135/ 125

mV (min)

180/ 190

mV (max)

Short-Circuit Current Limit

343

250

mV

Sense Voltage

415

mV (min)

mV (max)

Internal Compensation Ramp

92

mV

Voltage

52

mV(min)

132

mV(max)

0.49

0.30

(min)

0.70

(max)

50

mV

(with respect to feedback

32/ 25

mV(min)

VSSOP Package

78/ 85

mV(max)

SOIC Package

78/100

mV(max)

Output Over-Voltage

60

mV

20

mV(min)

110

mV(max)

(1)

voltage is greater than or equal to 7.2V.

(2)

The limits for the maximum duty cycle can not be specified since the part does not permit less than 100% maximum duty cycle

operation.

(3)

For this test, the FA/SD pin is pulled to ground using a 40K resistor.

(4)

For this test, the FA/SD pin is pulled to 5V using a 40K resistor.

(5)

The over-voltage protection is specified with respect to the feedback voltage. This is because the over-voltage protection tracks the

specification.

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