FOD2742A Просмотр технического описания (PDF) - Fairchild Semiconductor

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FOD2742A

Optically Isolated Error Amplifier

Fairchild Semiconductor 

Electrical Characteristics (TA = 25°C unless otherwise specified)

Input Characteristics

Symbol

Parameter

Test Conditions

Device Min. Typ. Max. Unit

VF

V REF

LED Forward Voltage

Reference Voltage

ILED = 10mA, VCOMP = VFB (Fig. 1)

ILED = 10mA, VCOMP = VFB (Fig. 1)

All

1.20 1.5 V

A 2.482 2.495 2.508 V

B 2.470 2.495 2.520 V

C 2.450 2.500 2.550 V

VREF (DEV) Deviation of VREF Over

Temperature

TA = -25°C to +85°C (Fig. 1)

All

3.5 17 mV

∆VRE Ratio of VREF Variation to ILED = 10mA ∆VCOMP = 10V to VREF

All

∆VCOMP the Output of the Error

Amplifier

(Fig. 2)

∆VCOMP = 36V to 10V

-0.5 -2.7 mV/

-0.3 -2.0 V

IREF Feedback Input Current

ILED = 10mA, R1 = 10KΩ (Fig. 3)

All

IREF (DEV) Deviation of IREF Over

TA = -25°C to +85°C (Fig. 3)

All

Temperature

2.2

4 µA

1.0 1.2 µA

ILED (MIN) Minimum Drive Current

VCOMP = VFB (Fig. 1)

All

I(OFF) Off-state Error Amplifier

VLED = 37V, VFB = 0 (Fig. 4)

All

Current

|ZOUT| Error Amplifier Output

VCOMP = VREF, ILED = 1mA to 20mA,

All

Impedance (see note 2) f ≥ 1.0kHz

0.45 1.0 mA

0.01 1.0 µA

0.15 0.5 Ω

Notes:

1. The deviation parameters VREF(DEV) and IREF(DEV) are defined as the differences between the maximum and

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

reference input voltage, ∆VREF, is defined as:

∆VREF (ppm/°C)

=

{----V----R----E---F---(--D----E----V---)--/--V----R----E---F----(--T----A-----=------2---5----°--C-----)--}-----×----1----0---6-

∆TA

where ∆TA is the rated operating free-air temperature range of the device.

2. The dynamic impedance is defined as |ZOUT| = ∆VCOMP/∆ILED. When the device is operating with two external

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

ZOUT, TOT = ∆--∆---V-I- ≈ ZOUT ×

1 + R-----1--

R2

©2003 Fairchild Semiconductor Corporation

FOD2742A, FOD2742B, FOD2742C Rev. 1.0.0

4

www.fairchildsemi.com

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