UCC2974

UCC3974

SLUS485A – JULY 2001 – REVISED NOVEMBER 2001

3

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electrical characteristics over recommended operating virtual junction temperature range,

supply current

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

I

V

s ppl c rrent

12 V

≤ VIN ≤ 25 V

1.7

3

mA

IIN

VIN supply current

VIN = 12 V,

MODE < 0.425 V

300

500

µA

UVLO threshold voltage

LOW to HIGH

3.6

4

4.4

V

UVLO hysteresis voltage

35

120

200

mV

output

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

High-level output voltage

12 V

≤ VIN ≤ 25 V

8

10.5

13

V

Low-level output voltage

MODE = 0.5 V,

ISINK = 1 mA

50

200

mV

Rise time

CL = 1 nF

170

350

ns

Fall time

CL = 1 nF

140

300

ns

oscillator

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Free-running oscillator frequency

12 V

≤ VIN ≤ 25 V,

BUCK = VIN

30

45

60

kH

Free-running synchronizable oscillator frequency

12 V

≤ VIN ≤ 25 V,

BUCK = VIN–3

62

220

kHz

Maximum duty cycle

FB = 1 V

100%

Minimum duty cycle

FB = 2 V

0%

BUCK input bias current

BUCK = VIN = 12 V

3

10

A

BUCK input bias current

BUCK = VIN = 25 V

3

10

µA

Zero detect threshold voltage

Measured at BUCK with respect to VIN,

12 V

≤ VIN ≤ 25 V

–2.4

–1.7

–1.1

V

error amplifier

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Input voltage

COMP = FB,

0

_C ≤ TA ≤ 70_C

1.465

1.5

1.535

V

Input voltage

COMP = FB,

–40

_C ≤ TA ≤ 85_C 1.455

1.5

1.545

V

Line regulation voltage

12 V

≤ VIN ≤ 25 V

1

5

mV

Input bias current

100

250

nA

Open loop gain

60

80

dB

High-level output voltage

FB = 1 V,

ISOURCE = 50 µA

3.5

3.7

4.2

V

Low-level output voltage

FB = 2 V,

ISINK = 50 µA

0.15

0.35

V

Output source current

FB = 1 V,

COMP = 2 V

–1.2

–0.3

mA

Output sink current

FB = 2 V,

COMP = 2 V

45

90

µA

Unity gain bandwidth

TJ = 25C,

See Note 1

2

5

MHz

NOTE 1:

Ensured by design, not production tested.