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FOD2742A_04 Datasheet, PDF (3/13 Pages) Fairchild Semiconductor – OPTICALLY ISOLATED ERROR AMPLIFIER | |||
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OPTICALLY ISOLATED
ERROR AMPLIFIER
FOD2742A
FOD2742B
FOD2742C
ELECTRICAL CHARACTERISTICS (TA = 25°C Unless otherwise speciï¬ed.)
INPUT CHARACTERISTICS
Parameter
Test Conditions Symbol Device Min. Typ. Max. Unit
LED Forward Voltage
(ILED = 10 mA, VCOMP = VFB) (ï¬g. 1)
VF
ALL
1.20 1.5 V
A 2.482 2.495 2.508 V
Reference Voltage
ILED = 10 mA, VCOMP = VFB (ï¬g. 1) VREF
B 2.470 2.495 2.520 V
C 2.450 2.500 2.550 V
Deviation of VREF over
temperature
TA = -25°C to +85°C (ï¬g. 1) VREF (DEV) ALL
3.5 17 mV
Ratio of VREF variation to the
output of the error ampliï¬er
ILED = 10 mA âVCOMP = 10V to VREF
(ï¬g. 2) âVCOMP = 36V to 10V
âVREF/
âVCOMP
ALL
-0.5 -2.7 mV/
-0.3 -2.0 V
Feedback Input Current
ILED = 10mA, R1 = 10K⦠(ï¬g. 3)
IREF
ALL
2.2
4 µA
Deviation of IREF over
temperature
TA = -25°C to +85°C (ï¬g. 3) IREF (DEV) ALL
1.0 1.2 µA
Minimum Drive Current
VCOMP = VFB (ï¬g. 1) ILED (MIN) ALL
0.45 1.0 mA
Off-state error ampliï¬er current
VLED = 37V, VFB = 0 (ï¬g. 4) I(OFF)
ALL
0.01 1.0 µA
Error ampliï¬er output impedance
(see note 2)
VCOMP = VREF, ILED = 1mA to 20mA,
f ⥠1.0 kHz
|ZOUT|
ALL
0.15 0.5 â¦
1. The deviation parameters VREF(DEV) and IREF(DEV) are deï¬ned as the differences between the maximum and minimum values
obtained over the rated temperature range. The average full-range temperature coefï¬cient of the reference input voltage, âVREF,
is deï¬ned as:
âVREF (ppm/°C) = -{---V----R----E---F---(--D----E----V---)--/--V----R----E---âF----(T--T--A--A-----=------2---5----°--C-----)--}-----Ã----1----0---6-
where âTA is the rated operating free-air temperature range of the device.
2. The dynamic impedance is deï¬ned as |ZOUT| = âVCOMP/âILED. When the device is operating with two external resistors
(see Figure 2), the total dynamic impedance of the circuit is given by:
ZOUT, TOT = â--â---V-I- â ZOUT Ã 1 + RR-----12--
© 2003 Fairchild Semiconductor Corporation
Page 3 of 13
12/9/04
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