©2010 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FOD2712A Rev. 1.0.1

4

Input Characteristics

Notes:

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

reference input voltage,

where

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

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

LED Forward Voltage

(Fig.1)

1.5

V

Reference Voltage

-40°C to +85°C

25°C

(Fig.1)

1.221

1.259

V

1.228

1.240

1.252

See Note 1

4

12

mV

Ratio of Vref Variation to the Output of the

Error Amplifier

(Fig. 2)

-1.5

-2.7

mV/V

Feedback Input Current

(Fig. 3)

0.15

0.5

µA

See Note 1

0.15

0.3

µA

Minimum Drive Current

55

80

µA

Off-state Error Amplifier Current

0.001

0.1

µA

Error Amplifier Output Impedance

See Note 2

f < 1kHZ

0.25

Ω

∆V

()

V

REF DEV

25°C

=

()

{} 10

6

×

∆T

A

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

=

Z

∆V

∆I

--------Z

OUT

1

R1

R2

--------

+

×

≈