UCC29900

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SLUS923B – APRIL 2009 – REVISED JUNE 2010

ELECTRICAL CHARACTERISTICS

over operating free-air temperature range (unless otherwise noted) VDD = 3.23 - 3.37 V, VSS = 0 V

SYMBOL

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Voltage Biasing

VDD current

5

mA

Voltage Monitoring

VIN UVLO threshold

Measured at VIN (rising)

2.32

2.38

2.44

V

VIN UVLO hysteresis

Measured at VIN (falling)

0.6

Startup delay

VIN = 3.3 V, Measured as start of HG switching

64

ms

after removal of UVLO fault

Input over voltage threshold

Measured at VIN rising

2.76

2.83

2.9

V

OVP delay

Measured between VIN and FAULT rising edges

20

ms

Feedback

FB rising threshold

1.45

2.53

FB falling threshold

0.8

1.85

V

Hysteresis

0.3

1

FB rising response time

2

ms

Soft Start

Max soft start period

Total duration of SS Operation, FB = 3.3 V

20

ms

Initial SS interval

Initial time delay between HG bursts in SS mode,

160

ms

FB = 0 V

Oscillator

Switching frequency

Measured at LG & HG, FB = 3.3 V

-6%

126.5

6%

kHz

LG period

First LG pulse after FB rising

2

Subsequent LG pulses, FB = 3.3 V

4

Last LG pulse after FB falling

2

HG period

FB = 3.3V

4

ms

LG period – light load

First LG during light load

4

Last LG during light load

4

HG period – light load

HG pulse during light load

8

Frequency Dithering

Dithering magnitude

Max frequency – min frequency

12

kHz

Dithering rate

Time to sweep from max to min and back to max

6

ms

frequencies

Min dithering frequency

Measured at LG, FB = 3.3 V

121

kHz

Max dithering frequency

Measured at LG, FB = 3.3 V

133

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