©2003 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FOD2742A, FOD2742B, FOD2742C Rev. 1.0.0

4

Input Characteristics

Notes:

minimum values obtained over the rated temperature range. The average full-range temperature coefficient of the

reference input voltage,

∆V

where

∆T

resistors (see Figure 2), the total dynamic impedance of the circuit is given by:

Symbol

Parameter

Test Conditions

Device Min.

Typ.

Max. Unit

LED Forward Voltage

All

1.20

1.5

V

Reference Voltage

A

2.482

2.495

2.508

V

B

2.470

2.495

2.520

V

C

2.450

2.500

2.550

V

Temperature

All

3.5

17

mV

∆V

RE

∆V

COMP

the Output of the Error

Amplifier

(Fig. 2)

∆V

All

-0.5

-2.7

mV/

V

∆V

-0.3

-2.0

Feedback Input Current

All

2.2

4

µA

Temperature

All

1.0

1.2

µA

Minimum Drive Current

All

0.45

1.0

mA

Off-state Error Amplifier

Current

All

0.01

1.0

µA

Error Amplifier Output

Impedance (see note 2)

f

≥ 1.0kHz

All

0.15

0.5

Ω

∆V

()

V

REF DEV

25°C

=

()

{} 10

6

×

∆T

A

-----------------------------------------------------------------------------------------------------

=

Z

∆V

∆I

--------Z

OUT

1

R1

R2

--------

+

×

≈