Integrated Circuits
Data Sheet
ET6500B
LIGHT-ACTIVATED BUFFER IC WITH INTERNAL PULL-UP AND ADJUSTABLE OPTICAL THRESHOLD
FEATURES
- Supply Voltage Range 4.5V to 18V
- 10k internal pull-up resistor on output
- Optical Sensitivity Adjustable over 7:1 range
- Operate point only 0.23mW/cm2 (480nW) typical
- Sensitivity tracks the temperature coefficient of power output of the GaAlAs LEDs
- Spectral response optimized for 880nm LED
APPLICATIONS
- Industrial Controls
- Light to voltage conversion
Table showing threshold adjustments.
| ADJ Resistor |
Normalized Threshold |
| Open |
1.00 |
| 10K |
1.95 |
| 4.7K |
2.73 |
| 2.2K |
3.80 |
| 1K |
4.98 |
| Short |
7.23 |
DESCRIPTION
This device incorporates an integral photodiode, amplifier, Schmitt trigger, and internally pulled-up output stage. An on-chip voltage regulator allows operation over a wide range of available supply voltage. The phase of thedigital output is considered to be the same as the optical input, so that the output is HI when the light source isON, and the output is LOW when the light source is OFF.An adjust pin (ADJ) is provided to allow the user to alter the optical threshold at which the output changes state.Decreasing the resistance between this pin and ground causes the output to switch at higher and higher inputlevels, to a maximum of about 1.66mW/cm 2 , or about 3.5µW on the photodiode.
ABSOLUTE MAXIMUM RATINGS
| Parameter |
Symbol |
Min. |
Max. |
Units |
Ref. |
| Operating Temperature Range |
TA |
-40 |
85 |
°C |
Note 1. |
| Supply Voltage Range |
VCCD |
-0.5 |
18 |
V |
Note 1. |
| Voltage at ADJ pin |
VADJ |
-0.5 |
3 |
V |
Note 1. |
| Voltage at OUT (output off) |
VOUT_MAX |
-0.5 |
18 |
V |
Note 1. |
| Sink current (output on) |
ISINK |
- |
30 |
mA |
Note 1. |
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, TA = 25°C and Vcc = 5V, ADJ pin open. LED on denotes an optical input of 720nW @ 880nm. LED off denotes a dark condition.
| Parameters |
Symbol |
Min. |
Typ. |
Max. |
Units |
Test Conditions |
| Vcc Voltage Range |
Vcc |
4.5 |
5 |
18 |
V |
- |
| Supply Current @ 5V, Output Low |
Icc1 |
1.5 |
2.1 |
2.9 |
mA |
LED source off |
| Supply Current @ 5V, Output High |
Icc2 |
1.8 |
2.5 |
3.5 |
mA |
LED source on |
| Supply Current @ 18V, Output Low |
Icc3 |
2.9 |
4.0 |
5.6 |
mA |
LED source off |
| Supply Current @ 18V, Output High |
Icc4 |
2.2 |
3.1 |
4.4 |
mA |
LED source on |
| Dark-Light Optical Threshold, 5V |
PT5 |
320 |
480 |
720 |
nW |
ADJ open |
| Dark-Light Optical Threshold, 18V |
PT18 |
320 |
520 |
790 |
nW |
ADJ open |
| Optical Hysteresis Ratio |
HYS |
1.20 |
1.33 |
1.50 |
- |
- |
| Low Level Output, 5V |
VOL1 |
- |
290 |
400 |
mV |
LED off, ADJ open |
| Low Level Output, 18V |
VOL2 |
- |
285 |
400 |
mV |
LED off, ADJ open |
| Pull-Up Resistor Value |
R |
6 |
10 |
14 |
kohm |
- |
AC SWITCHING CHARACTERISTICS
Values given at VCC=5V, TA = 25°C, CL = 15pF, and RL = 10K, and with optical input @ 940 nW (this is equal to 1.3 times the threshold).
| Parameters |
Symbol |
Min. |
Typ. |
Max. |
Units |
Test Conditions |
| Propagation delay, dark to light |
TPLH |
- |
1.8 |
3.6 |
s |
Note 1. |
| Propagation delay, light to dark |
TPHL |
- |
2.0 |
4.0 |
s |
Note 1. |
| Output Rise Time |
TR |
- |
440 |
600 |
ns |
Note 1. |
| Output Fall Time |
TF |
- |
16 |
30 |
ns |
Note 1. |
GND ADJ NOTES:
- This is not a test parameter, but for information only.
- The chip dimensions are 44 x 44 x 10 mils. The photodiode is located 21.3 mils from the left edge, and 12.7 mils from the top edge. (One mil = .001 inch.)
ETIC RESERVES THE RIGHT TO MAKE CHANGES AT ANY TIME TO IMPROVE THE DESIGN AND TO SUPPLY THE BEST PRODUCT.
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