Datasheet

5
Notes:
2. Optical measurements are made using small–angle incident radiation from light–emitting diode optical sources. Visible 640 nm LEDs and infrared
940 nm LEDs are used for nal product testing for compatibility with high–volume production.
3. The 640 nm irradiance Ee is supplied by an AlInGaP light–emitting diode with the following characteristics: peak wavelength lp = 640 nm and
spectral halfwidth Dl½ = 17 nm.
4. The 940 nm irradiance Ee is supplied by a GaAs light–emitting diode with the following characteristics: peak wavelength lp = 940 nm and spectral
halfwidth Dl½ = 40 nm.
5. Integration time Tint, is dependent on internal oscillator frequency (fosc) and on the integration eld value in the timing register as described in
the Register Set section. For nominal fosc = 735 kHz, nominal Tint = (number of clock cycles)/fosc.
Field value 00: Tint = (11 • 918)/fosc = 13.7 ms
Field value 01: Tint = (81 • 918)/fosc = 101 ms
Field value 10: Tint = (322 • 918)/fosc = 402 ms
Scaling between integration times vary proportionally as follows:
11/322 = 0.034 (eld value 00), 81/322 = 0.252 (eld value 01), and 322/322 = 1 (eld value 10).
6. Full scale ADC count value is limited by the fact that there is a maximum of one count per two oscillator frequency periods and also by a 2–count
oset.
Full scale ADC count value = ((number of clock cycles)/2 - 2)
Field value 00: Full scale ADC count value = ((11 • 918)/2 - 2) = 5047
Field value 01: Full scale ADC count value = ((81 • 918)/2 - 2) = 37177
Field value 10: Full scale ADC count value = 65535, which is limited by 16 bit register. This full scale ADC count value is reached for 131074
clock cycles, which occurs for Tint = 178 ms for nominal fosc = 735 kHz.
7. Low gain mode has 16x lower gain than high gain mode: (1/16 = 0.0625).
8. For sensor Lux calculation, please refer to the empirical formula in Application Note. It is based on measured Ch0 and Ch1 ADC count values for the
light source specied. Actual Lux is obtained with a commercial luxmeter. The range of the (sensor Lux) / (actual Lux) ratio is estimated based on
the variation of the 640 nm and 940 nm optical parameters. Devices are not 100% tested with uorescent or incandescent light sources.
CH1/CH0 Sensor Lux Formula
0 ≤ CH1/CH0 ≤ 0.52 Sensor Lux = (0.0315 x CH0) – (0.0593 x CH0 x ((CH1/CH0)
1.4
))
0.52 ≤ CH1/CH0 ≤ 0.65 Sensor Lux = (0.0229 x CH0) – (0.0291 x CH1)
0.65 ≤ CH1/CH0 ≤ 0.80 Sensor Lux = (0.0157 x CH0) – (0.0180 x CH1)
0.80 ≤ CH1/CH0 ≤ 1.30 Sensor Lux = (0.00338 x CH0) – (0.00260 x CH1)
CH1/CH0 ≥ 1.30 Sensor Lux = 0
AC Electrical Characteristics (V
DD
= 3 V, Ta = 25 ºC)
Parameter † Min. Typ. Max. Unit
t
(CONV)
Conversion time 12 100 400 ms
f
(SCL)
Clock frequency - - 400 kHz
t
(BUF)
Bus free time between start and stop condition 1.3 - - μs
t
(HDSTA)
Hold time after (repeated) start condition. After this
period, the rst clock is generated.
0.6 - - μs
t
(SUSTA)
Repeated start condition setup time 0.6 - - μs
t
(SUSTO)
Stop condition setup time 0.6 - - μs
t
(HDDAT)
Data hold time 0 - 0.9 μs
t
(SUDAT)
Data setup time 100 - - ns
t
(LOW)
SCL clock low period 1.3 - - μs
t
(HIGH)
SCL clock high period 0.6 - - μs
t
F
Clock/data fall time - - 300 ns
t
R
Clock/data rise time - - 300 ns
C
j
Input pin capacitance - - 10 pF
† Specied by design and characterization; not production tested.