LM2717

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SNVS253D – MAY 2005 – REVISED MARCH 2013

Electrical Characteristics (continued)

Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating

Temperature Range (TJ = −40°C to +125°C). VIN = 5V, IL = 0A, and FSW = 300kHz unless otherwise specified.

Symbol

Parameter

Conditions

Min(1)

Typ(2)

Max(1)

Units

ICL1

(3)

Fixed Buck Switch Current

VIN = 8V

(4)

2.2

A

Limit

ICL2

(3)

Adjustable Buck Switch

VIN = 8V

(4)

3.2

A

Current Limit

IB1

Fixed Buck FB Pin Bias

VIN = 20V

65

µA

Current(5)

IB2

Adjustable Buck FB Pin Bias

VIN = 20V

65

nA

Current(5)

VIN

Input Voltage Range

4

20

V

gm1

Fixed Buck Error Amp

ΔI = 20µA

1340

µmho

Transconductance

gm2

Adjustable Buck Error Amp

ΔI = 20µA

1360

µmho

Transconductance

AV1

Fixed Buck Error Amp Voltage

134

V/V

Gain

AV2

Adjustable Buck Error Amp

136

V/V

Voltage Gain

DMAX

Maximum Duty Cycle

89

93

%

FSW

Switching Frequency

RF = 46.4k

200

300

400

kHz

RF = 22.6k

475

600

775

kHz

ISHDN1

Fixed Buck Shutdown Pin

0V < VSHDN1 < 7.5V

−5

5

µA

Current

ISHDN2

Adjustable Buck Shutdown Pin

0V < VSHDN2 < 7.5V

−5

5

µA

Current

IL1

Fixed Buck Switch Leakage

VIN = 20V

0.01

5

µA

Current

IL2

Adjustable Buck Switch

VIN = 20V

0.01

5

µA

Leakage Current

RDSON1

Fixed Buck Switch RDSON

(6)

160

m

Ω

RDSON2

Adjustable Buck Switch

160

m

Ω

RDSON

(6)

ThSHDN1

Fixed Buck SHDN Threshold

Output High

1.8

1.36

V

Output Low

1.33

0.7

ThSHDN2

Adjustable Buck SHDN

Output High

1.8

1.36

V

Threshold

Output Low

1.33

0.7

ISS1

Fixed Buck Soft Start Pin

4

9

15

µA

Current

ISS2

Adjustable Buck Soft Start Pin

4

9

15

µA

Current

UVP

On Threshold

4

3.8

V

Off Threshold

3.6

3.3

θJA

Thermal Resistance(7)

TSSOP, package only

115

°C/W

(3)

Duty cycle affects current limit due to ramp generator.

(4)

Current limit at 0% duty cycle. See TYPICAL PERFORMANCE section for Switch Current Limit vs. VIN

(5)

Bias current flows into FB pin.

(6)

Includes the bond wires, RDSON from VIN pin(s) to SW pin.

(7)

Refer to Texas Instruments packaging website for more detailed thermal information and mounting techniques for the TSSOP package.

Copyright © 2005–2013, Texas Instruments Incorporated

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