Electrical Characteristics (T = 25°C unless otherwise specified)
A
Input Characteristics
Symbol
Parameter
Test Conditions
Device Min. Typ. Max. Unit
V
LED Forward Voltage
Reference Voltage
I
I
= 10mA, V
= 10mA, V
= V (Fig.1)
All
1.5
V
V
F
LED
COMP
COMP
FB
V
= V
FOD2741A 2.482 2.495 2.508
FOD2741B 2.470 2.495 2.520
FOD2741C 2.450 2.500 2.550
REF
LED
FB
V
V
(4)
V
Deviation of V
Temperature
Over T = -25°C to +85°C
All
4.5
17
mV
REF (DEV)
REF
A
∆V
∆V
/
Ratio of V
to the Output of the
Error Amplifier
Variation
I
I
= 10mA ∆V
∆V
= 10V to V
REF
All
-1.0
-0.5
-2.7 mV/V
-2.0
REF
REF
LED
LED
COMP
COMP
COMP
= 36V to 10V
I
Feedback Input
Current
= 10mA, R = 10kΩ (Fig. 3)
All
All
1.5
0.4
4
µA
µA
REF
1
(4)
I
Deviation of I
Temperature
Over T = -25°C to +85°C
1.2
REF (DEV)
REF
A
I
Minimum Drive Current V
= V (Fig. 1)
All
All
0.45
0.05
1.0
1.0
mA
µA
LED (MIN)
COMP
FB
I
Off-state Error
V
= 37V, V = 0 (Fig. 4)
LED FB
(OFF)
Amplifier Current
|Z
|
Error Amplifier Output
impedance
V
= V , I
= 1mA to 20mA,
All
0.15
0.5
Ω
OUT
COMP
REF LED
(5)
f ≥ 1.0 kHz
Output Characteristics
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
I
Collector Dark Current
V
= 10V (Fig. 5)
50
nA
V
CEO
CE
BV
BV
Emitter-Collector Voltage Breakdown
Collector-Emitter Voltage Breakdown
I = 100µA
7
ECO
CEO
E
I = 1.0mA
70
V
C
Transfer Characteristics
Parameter
Symbol
Test Conditions
Min.
Typ.
Max.
Unit
CTR
Current Transfer Ratio
I
= 10mA, V
= V ,
FB
100
200
%
LED
COMP
V
= 5V (Fig. 6)
CE
V
Collector-Emitter Saturation
Voltage
I
= 10mA, V
= V
0.4
V
CE (SAT)
LED
COMP
FB,
I = 2.5mA (Fig. 6)
C
Notes:
4. The deviation parameters V
and I
are defined as the differences between the maximum and
REF(DEV)
REF(DEV)
minimum values obtained over the rated temperature range. The average full-range temperature coefficient of the
reference input voltage, ∆V , is defined as:
REF
{VREF(DEV)/VREF(TA = 25°C)} × 106
∆VREF (ppm/°C) = ----------------------------------------------------------------------------------------------------
∆TA
where ∆T is the rated operating free-air temperature range of the device.
A
5. The dynamic impedance is defined as |Z
| = ∆V
/ ∆I
. When the device is operating with two external
OUT
COMP
LED
resistors (see Figure 2), the total dynamic impedance of the circuit is given by:
∆V R1
ZOUT, TOT = ------- ≈ ZOUT × 1 + -------
∆I
R2
©2004 Fairchild Semiconductor Corporation
FOD2741A, FOD2741B, FOD2741C Rev. 1.0.1
www.fairchildsemi.com
4