LM3477

SNVS141K – OCTOBER 2000 – REVISED MARCH 2013

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Electrical Characteristics

(1) (continued)

Specifications in Standard type face are for TJ = 25°C, and in bold type face apply over the full Operating Temperature

Range. Unless otherwise specified, VIN = 12V.

Symbol

Parameter

Conditions

Typical

Limit

Units

ISUPPLY

Supply Current (switching)

(2)

2.0

mA

3.0

mA (max)

IQ

Quiescent Current in Shutdown Mode

(3), V

IN = 5V

5

µA

8

µA (max)

VCL(O)

Current Limit Voltage at 0% Duty Cycle

LM3477

155

mV

130/125

mV (min)

185/190

mV (max)

LM3477A

165

mV

140/135

mV (min)

195/200

mV (max)

VCL(100)

Current Limit Voltage at 100% Duty

LM3477

74

mV

Cycle

50/43

mV (min)

98/98

mV (max)

LM3477A

65

mV

41/25

mV (min)

89/98

mV (max)

VSC

Short-Circuit Current Limit Sense

VIN = 5V, LM3477

350

mV

Voltage

270

mV (min)

420

mV (max)

VIN = 5V, LM3477A

310

mV

260

mV (min)

380

mV (max)

VSL

Internal Compensation Ramp Voltage

VIN = 5V, LM3477

83

mV

Height

VIN = 5V, LM3477A

103

VOVP

Output Over-voltage Protection (with

VCOMP = 1.4V

50

mV

32/25

respect to feedback voltage) (4)

mV(min)

78/85

mV(max)

VOVP(HYS)

Output Over-Voltage Protection

VCOMP = 1.4V

60

mV

Hysteresis(4)

20

mV(min)

110

mV(max)

Gm

Error Amplifier Transconductance

VCOMP = 1.4V

750

µmho

IEAO = 100µA (Source/Sink)

600/365

µmho (min)

1000/1265

µmho (max)

AVOL

Error Amplifier Voltage Gain

VCOMP = 1.4V

38

V/V

IEAO = 100µA (Source/Sink)

30

V/V (min)

42

V/V (max)

IEAO

Error Amplifier Output Current (Source/

Source, VCOMP = 1.4V, VFB =

100

µA

Sink)

0V

75/50

µA (min)

130/160

µA (max)

Sink, VCOMP = 1.4V, VFB = 1.4V

−140

µA

−110/−95

µA (min)

−170/−180

µA (max)

VEAO

Error Amplifier Output Voltage Swing

Upper Limit

2.2

V

VFB = 0V

2.0

V(min)

COMP Pin = Floating

2.35

V(max)

Lower Limit

0.75

V

VFB = 1.4V

0.5

V(min)

0.95

V(max)

TSS

Internal Soft-Start Delay

VFB = 1.2V, VCOMP = Floating

5

msec

Tr

Drive Pin Rise Time

CGS = 3000pF, VDR = 0 to 3V

25

ns

Tf

Drive Pin Fall Time

CGS = 3000pF, VDR = 0 to 3V

25

ns

(2)

For this test, the COMP/SD pin must be left floating.

(3)

For this test, the COMP/SD pin must be pulled low.

(4)

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

feedback voltage. The overvoltage protection threshold is given by adding the feedback voltage, VFB to the over-voltage protection

specification.

4

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