Datasheet

Designing the VEML6070 UV Light Sensor
Into Applications
Application Note
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APPLICATION NOTE
Revision: 26-Mar-18
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Document Number: 84310
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0x70 is the only command register where shut-down, integration time, and acknowledge activity settings are handled.
As previously discussed, integration time also depends on the external resistor at pin 4. Together with a R
SET
value of 270 kΩ,
the table below shows UV light data values that lead to the UVI values shown on the left side.
As previously mentioned, other resistor values lead to other integration times with different output data. At 540 kΩ, the 270 kΩ
output data values are doubled, and the 540 kΩ values are doubled at 1 MΩ, which means that the sensitivity is also doubled.
VEML6070 light data is available at 0x71 (LSB) and 0x73 (MSB). Together they show the whole 16-bit value and report the
present UV light conditions. This 16-bit value is transferred into decimal form and becomes the base for calculating the
corresponding UVI.
As already stated, the above values are evaluated taking care to weigh the wavelength and response performance of the
VEML6070. Factoring in the R
SET
value and integration time leads to the UVI values.
TABLE 2 - COMMAND REGISTER BITS DESCRIPTION
COMMAND FORMAT
Reserved ACK ACK_THD IT Reserved SD
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
00ACKTHDIT1IT01SD
DESCRIPTION
Reserved Reserved
ACK Acknowledge activity setting
ACK_THD Acknowledge threshold window setting for byte mode usage
IT Integration time setting
SD Shutdown mode setting
UVI R
SET
= 270 kΩ; IT = 1T R
SET
= 270 kΩ; IT = 2T R
SET
= 270 kΩ; IT = 4T UV-INDEX
≥ 11 ≥ 2055 ≥ 4109 ≥ 8217
Extreme
8 to 10 1494 to 2054 2989 to 4108 5977 to 8216
Very High
6, 7 1121 to 1494 2242 to 2988 4483 to 5976
High
3 to 5 561 to 1120 1121 to 2241 2241 to 4482
Moderate
0 to 2 0 to 560 0 to 1120 0 to 2240
Low
UVI R
SET
= 540 kΩ; IT = 1T R
SET
= 540 kΩ; IT = 2T R
SET
= 540 kΩ; IT = 4T UV-INDEX
0 to 2 0 to 1120 0 to 2240 0 to 4480
Low
3 to 5 1121 to 2241 2241 to 4482 4481 to 8964
Moderate
6, 7 2242 to 2988 4483 to 5976 8965 to 11 952
High
8 to 10 2989 to 4108 5977 to 8216 11 953 to 16 432
Very High
≥ 11 ≥ 4109 ≥ 8217 ≥ 16 433
Extreme
UVI R
SET
= 1 MΩ; IT = 1T R
SET
= 1 MΩ; IT = 2T R
SET
= 1 MΩ; IT = 4T UV-INDEX
0 to 2 0 to 2241 0 to 4482 0 to 8964
Low
3 to 5 2242 to 4482 4483 to 8964 8965 to 17 928
Moderate
6, 7 4483 to 5976 8965 to 11 952 17 929 to 23 904
High
8 to 10 5977 to 8217 11 953 to 16434 23 905 to 32 868
Very High
≥ 11 ≥ 8218 ≥ 16 435 ≥ 32 869
Extreme