TSL230R−LF, TSL230AR−LF, TSL230BR−LF
PROGRAMMABLE LIGHT-TO-FREQUENCY CONVERTERS
TAOS079A
−
OCTOBER 2006
TYPICAL CHARACTERISTICS
OUTPUT FREQUENCY
vs
SUPPLY VOLTAGE
1.010
T
A
= 25°C
f
O
= 100 kHz
1.005
Normalized Output Frequency
1.000
0.995
0.990
0.985
0.980
2.5
3
3.5
4
4.5
5
5.5
V
DD
−
Supply Voltage
−
V
Figure 5
APPLICATION INFORMATION
Power-supply considerations
Power-supply lines must be decoupled by a 0.01-μF to 0.1-μF capacitor with short leads placed close to the
device package. A low-noise power supply is required to minimize jitter on output pulses.
Input interface
A low-impedance electrical connection between the device OE pin and the device GND pin is required for
improved noise immunity.
Output interface
The output of the device is designed to drive a standard TTL or CMOS logic input over short distances. If lines
greater than 12 inches are used on the output, a buffer or line driver is recommended.
Sensitivity adjustment
Sensitivity is controlled by two logic inputs, S0 and S1. Sensitivity is adjusted using an electronic iris technique
— effectively an aperture control — to change the response of the device to a given amount of light. The
sensitivity can be set to one of three levels: 1×, 10×, or 100×, providing two decades of adjustment. This allows
the responsivity of the device to be optimized to a given light level while preserving the full-scale
output-frequency range. Changing of sensitivity also changes the effective photodiode area by the same factor.
The
LUMENOLOGY
r
Company
r
r
Copyright
E
2006, TAOS Inc.
www.taosinc.com
5
TAOS [ TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS ]
