LM3551, LM3552

SNVS371D – AUGUST 2005 – REVISED MAY 2013

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Electrical Characteristics

(1) (2)

range (-40°C

(3)

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Quiescent Current

1.47

2.0

mA

2.55

5.0

Shutdown Current

µA

V(EN) = 0V, LM3552

0.1

2.3

(4)

Switch Current Limit

(5)

2.1

A

Feedback Voltage

1.2285

1.265

1.2915

V

(6)

Feedback Pin Bias Current

50

nA

Error Amp Transconductance

ΔI = 5µA

135

µmho

Error Amp Voltage Gain

135

V/V

Maximum Duty Cycle

92.5

%

Switching Frequency

0.9

1.25

1.6

MHz

Shutdown Pin Current

3.0

6

µA

(LM3551)

Enable Pin Current

3.0

6

µA

(LM3552)

26

T/F Pin Current

nA

22

SW Pin Leakage Current

0.07

8

µA

0.165

Ω

FET-T Leakage Current

0.1

µA

0.98

Ω

FET-F Leakage Current

0.1

µA

0.36

Ω

Output High

1.2

Shutdown/Enable Pin

V

Threshold

Output Low

0.3

Output High

1.2

T/F Pin Threshold

V

Output Low

0.3

On Threshold

2.25

2.48

2.70

Under Voltage Protection

UVP

V

Thresholds

Off Threshold

2.43

2.58

2.77

On Threshold

11.3

12.4

14

Over Voltage Protection

OVP

V

Thresholds

Off Threshold

9.2

10.6

12

Flash Timeout trip-point

0.99

1.16

1.32

V

Flash Timeout Current

1.12

1.4

1.68

µA

Soft-Start Voltage

1.18

1.25

1.32

V

Soft-Start Current

10

11.5

13

µA

(1)

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

(2)

Min and Max limits are specified by design, test, or statistical analysis. Typical (Typ) numbers represent the most likely norm. Unless

(3)

(4)

Duty cycle affects current limit due to ramp generator.

(5)

(6)

Bias current flows into FB pin.

4

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