FOD2743A Datasheet, PDF (3/15 Pages) Fairchild Semiconductor – OPTICALLY ISOLATED ERROR AMPLIFIER

OPTICALLY ISOLATED
ERROR AMPLIFIER
FOD2743A
FOD2743B
FOD2743C
ELECTRICAL CHARACTERISTICS (T_A = 25°C Unless otherwise specified.)
INPUT CHARACTERISTICS
Parameter
LED Forward Voltage
Reference Voltage
Deviation of V_REF over
temperature
Ratio of V_REF variation to the
output of the error amplifier
Feedback Input Current
Deviation of I_REF over
temperature
Minimum Drive Current
Off-state error amplifier current
Error amplifier output impedance
(see note 2)
Test Conditions
(I_LED = 1 mA, V_COMP = V_FB) (fig.1)
I_LED = 1 mA, V_COMP = V_FB
Symbol
V_F
V_REF
Device Min. Typ. Max. Unit
ALL
1.07 1.2 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
T_A = -25°C to +85°C V_{REF (DEV)} ALL
4.5 17 mV
I_LED = 1 mA
∆V_COMP = 10V to V_REF
∆V_COMP = 36V to 10V
∆V_REF/
∆V_COMP
ALL
I_LED = 1mA, R₁ = 10kΩ (fig 3)
I_REF
ALL
-0.4 -2.7 _mV/
-0.3 -2.0 ^V
2
4 µA
T_A = -25°C to +85°C I_{REF (DEV)} ALL
1 1.2 µA
V_COMP = V_FB (fig.1) I_{LED (MIN)} ALL
V_LED = 37V, V_FB = 0 (fig 4.) I_(OFF)
ALL
V_COMP = V_REF, I_LED = 1mA to 20mA,
f ≥ 1.0 kHz
|Z_OUT|
ALL
0.45 1.0 mA
0.001 1.0 µA
0.15 0.5 Ω
1. The deviation parameters V_REF(DEV) and I_REF(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, ∆V_REF,
is defined as:
∆V_REF (ppm/°C) = ^{----V----^R----^E---^F---⁽--^D----^E----^V---⁾--/--V----^R----^E---_∆^F----⁽_T--T--A--^A-----=------2---5----°--C-----⁾--^}-----^×----1----0---⁶-
where ∆T_A is the rated operating free-air temperature range of the device.
2. The dynamic impedance is defined as |Z_OUT| = ∆V_COMP/∆I_LED. When the device is operating with two external resistors (see
Figure 2), the total dynamic impedance of the circuit is given by:
Z_{OUT, TOT} = ^∆--_∆---V-I- ≈ Z_OUT × 1 + ^RR-----12--
© 2004 Fairchild Semiconductor Corporation
Page 3 of 15
4/8/04