Avago Technologies ACPL-224-500E - Manual (Page 13)

AV02-4387EN 11 Avago Technologies
Calculate the LED Lifetime Performance
in Optocouplers to Predict Reliability
Acceleration Factor Based on Black Model
An Acceleration Factor (AF) based on the Black
Model can be used to correlate the actual HTOL
stress test data points, taken at elevated tempera-
tures and stress levels in short periods of time, to
the expected lifetime according to the actual ap-
plication operating conditions of the optocoupler.
However, not all the values needed to calculate
the AF value are on the vendor data sheets. Often,
you may have to contact the vendor to obtain the
necessary information to do the calculations.
Table 1. Avago optocouplers with AlGaAs (type 1) LED
Product Family Part Number
10MBD LOGIC ACNV2601, HCNW137
5MBD LOGIC HCNW2211
1MBD TRANSISTOR ACPL-M50L/054L
100KBD DARLINGTON HCNW138
ANALOG HCNR200/201, HCNW4562
ISOLATION AMPLIFIER ACPL-796J/C784/785J
ACPL-7900/7970/C797/C790
HCPL-7840/7860
GATE DRIVER ACPL-331J/332J, ACNW3190
HCNW3120, HCPL-316J/314J
IPM DRIVER ACNV4506, ACPL-P484/W484
HCNW4503/4506
Table 2. Avago optocouplers with AlGaAs (type 2) LED
Product Family Part Number
HIGH SPEED CMOS ACPL-072L/772L
HCPL-0710/0720
20MBD LOGIC HCPL-2400/2430
10MBD LOGIC ACPL-M61L/064L
8MBD LOGIC HCPL-0300/2300
100KBD DARLINGTON HCPL-070A/4701
ANALOG ACPL-K376, HCPL-4562
Table 3. Avago optocouplers with GaAsP LED
Product Family Part Number
HIGH SPEED CMOS HCPL-0708/0738
15MBD HS CMOS ACPL-071L/074L
15MBD LOGIC ACPL-M60L/W60L
HCPL-060L/263L
10MBD LOGIC ACPL-P611/W611
6N137, HCPL-2611/2630/M611
5MBD LOGIC HCPL-0201/2231
1MBD TRANSISTOR 6N136, HCPL-050L/053L
HCPL-250L/253L
100KBD DARLINGTON 4N45, 6N138,
HCPL-070L/073L, HCPL-270L/273L/M700
ANALOG ACPL-K370,
HCPL-2602/4100
GATE DRIVER ACPL-3130/W302/P314/H312
HCPL-3120 /3150
IPM DRIVER ACPL-4800/P480/W454
HCPL-0453/0454/4504/ M456










−




=
acc norm
a
N
norm
acc
T T K
E
J
J
AF
1 1
exp --- Equation (1)
AF = Acce leration Factor
Jacc = Accelerated current density (HTOL stress input
current)
Jnorm = Nominal operation current density (applica-
tion operating input current at 100% duty cycle)
Ea = Activation energy of 0.43 eV
K = Boltzmann’s constant of 8.62 x 10-5 eV/K
Tnorm = Nominal operating temperature (application
ambient operating temperature)
Tacc = Accelerated operating temperature (HTOL stress
temperature)
N = Model
parameter of 2
For the same CTR degradation performance, the
field lifetime of the LED can be projected accord-
ing to following equation:
LED projected field hours = AF x LED stress hours
--- Equation (2)
To illustrate the AF as a multiplier, consider a nu-
merical example using stress data from one of
Avago’s optocouplers. The stress data conditions
include: IF = 20mA, temperature = 125°C, and LED
type “AA”. At a stress test length of 1000 hours, the
CTR degradation is measured as 99.2%. If that op-
tocoupler is used with application conditions of
IF= 5mA (assume 100% duty cycle operation) and
an ambient temperature of 60°C, the AF is calcu-
lated as:
7 . 184
125 273
1
60 273
1
10 62 . 8
43 . 0
exp
5
20
5
2
≈










+
−
+ ×






=
− mA
mA
AF