©2004 Fairchild Semiconductor Corporation www.fairchildsemi.com
FOD2743A, FOD2743B, FOD2743C Rev. 1.0.1 4
FOD2743A, FOD2743B, FOD2743C — Optically Isolated Error Amplifier
Electrical Characteristics
(T
A
= 25°C unless otherwise specified)
Input Characteristics
Output Characteristics
Transfer Characteristics
Notes:
2. 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:
where
∆
T
A
is the rated operating free-air temperature range of the device.
3. 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:
Symbol Parameter Test Conditions Device Min. Typ. Max. Unit
V
F
LED Forward Voltage I
LED
= 1mA, V
COMP
= V
FB
(Fig.1) All 1.07 1.2 V
V
REF
Reference Voltage I
LED
= 1mA, V
COMP
= V
FB
FOD2743A 2.482 2.495 2.508 V
FOD2743B 2.470 2.495 2.520 V
FOD2743C 2.450 2.500 2.550 V
V
REF (DEV)
(2)
Deviation of V
REF
Over
Temperature
(2)
T
A
= -25°C to +85°C All 4.5 17 mV
∆
V
REF
/
∆
V
COMP
Ratio of V
REF
Variation
to the Output of the
Error Amplifier
I
LED
= 1mA
∆
V
COMP
= 10V to V
REF
All -0.4 -2.7 mV/V
∆
V
COMP
= 36V to 10V -0.3 -2.0
I
REF
Feedback Input Current I
LED
= 1mA, R
1
= 10k
Ω
(Fig. 3) All 2 4 µA
I
REF (DEV)
(2)
Deviation of I
REF
Over
Temperature
T
A
= -25°C to +85°C All 1 1.2 µA
I
LED (MIN)
Minimum Drive Current V
COMP
= V
FB
(Fig.1) All 0.45 1.0 mA
I
(OFF)
Off-State Error
Amplifier Current
V
LED
= 37V, V
FB
= 0 (Fig. 4) All 0.001 1.0 µA
|Z
OUT
| Error Amplifier Output
Impedance
(3)
V
COMP
= V
REF
, I
LED
= 1mA to 20mA,
f
≥
1.0 kHz
All 0.15 0.5
Ω
Symbol Parameter Test Conditions Min. Typ. Max. Unit
I
CEO
Collector Dark Current V
CE
= 10V (Fig. 5) 1 50 nA
BV
ECO
Emitter-Collector Voltage Breakdown I
E
= 100µA 7 10 V
BV
CEO
Collector-Emitter Voltage Breakdown I
C
= 1.0mA 70 100 V
Symbol
Parameter
Test Conditions Min. Typ. Max. Unit
CTR Current Transfer Ratio I
LED
= 1mA, V
COMP
= V
FB
,
V
CE
= 5V (Fig. 6)
50 100 %
V
CE
(SAT)
Collector-Emitter Saturation
Voltage
I
LED
= 1mA, V
COMP
= V
FB,
I
C
= 0.1mA (Fig. 6)
0.4 V
∆V
REF
ppm/°C()
V
REF DEV()
/V
REF
T
A
25°C=(){}10
6
×
∆T
A
-----------------------------------------------------------------------------------------------------=
Z
OUT, TOT
=
∆V
∆I
--------Z
OUT
1
R1
R2
--------+×≈