AN-073E Rev.1.1

April-2011

7

FA5695

Fuji Electric Co., Ltd.

http://www.fujielectric.co.jp/products/semiconductor/

(3)Electrical Characteristics (Unless otherwise specified, Ta=25°C, Vcc=12V, Vfb=1.0V,

Vcomp=5.0V, Rrt=82kΩ、Vovp=1.0V, Vis=100mV)

ERROR AMPLIFIER (FB,COMP Pin)

Item

Symbol

Condition

MIN

TYP

MAX

Unit

Voltage Feedback Input

Threshold

Vfb

2.465

2.500

2.535

V

Line Regulation

Regline

Vcc=10V to 26V

-20

-10

-

mV

Temperature stability

VdT

Tj=-30°C to +85°C

±0.5

mV/°C

Transconductance

Gm

50

75

100

umho

Output current at startup

Io_ss

Source:V(FB)=1.0V

-20

-40

-60

uA

Output Current

Io

Source:V(FB)=1.0V

Sink:V(FB)=4.0V

-40

30

-60

50

-80

70

uA

RAMP OSCILLATOR (RT Pin)

Item

Symbol

Condition

MIN

TYP

MAX

Unit

Maximum on range

Tonmax

V(COMP)=5.0V

V(FB)=Vfb

24

30

36

Us

Maximum on range

(Soft start)

Tonmax_

soft-start

V(COMP)=5.0V

V(FB)=1.0V

18

24

30

us

Maximum oscillating frequency

Fmax

V(COMP)=1.0V

340

400

460

kHz

RT output voltage

Vrt

0.90

1.15

1.40

V

PWM comparator (COMP Pin)

Item

Symbol

Condition

MIN

TYP

MAX

Unit

Input threshold voltage

Vthcomp

0.6

0.7

0.8

V

SOFT START (FB Pin)

Item

Symbol

Condition

MIN

TYP

MAX

Unit

Soft start cancellation voltage

Vthsoft

V(COMP)=5.0V

Ton>Tonmax*90%

0.94*Vfb

V

OVERVOLTAGE COMPARATER (FB Pin)

Item

Symbol

Condition

MIN

TYP

MAX

Unit

Vsovph

V(FB)=2.5V→3.0V

1.060*Vfb

1.080*Vfb

1.095*Vfb

V

Vsovpl

V(FB)=3.0V→2.5V

1.020*Vfb

1.040*Vfb

1.060*Vfb

V

Static OVP threshold voltage

Vsovphys

Vsovph-Vsovpl

0.030*Vfb

0.040*Vfb

0.060*Vfb

V

Dynamic OVP

threshold voltage

Vdovp

V(FB)=2.5V→3.0V

Ton=Tonmax*70%

1.025*Vfb

1.050*Vfb

1.075*Vfb

V

FB SHORT COMPARATOR (FB Pin)

Item

Symbol

Condition

MIN

TYP

MAX

Unit

Input threshold voltage

Vthfb

0.1

0.3

0.5

V

Pull-up current

Ipullup

V(FB)=2.5V

1.2

1.8

2.4

uA

CURRENT SENSE COMPARATOR (IS Pin)

Item

Symbol

Condition

MIN

TYP

MAX

Unit

IS threshold voltage

Vthis

-0.58

-0.60

-0.62

V

IS threshold voltage

temperature characteristics

Vthisdt

Tj=-30°C to +85°C

-1.5

1.5

%

Output delay

Tphl

-

200

500

ns

Zero current detection voltage

Vzcd

-15.0

-10.0

-5.0

mV

Zero current detection delay

Tzcd

0.3

0.9

1.5

us