VEML7700

Part: VEML7700, Vishay Semiconductors

Type: High-Accuracy Ambient Light Sensor

Description: The VEML7700 is a very high sensitivity, high accuracy ambient light sensor with a 16-bit A/D converter, I2C interface, and a dynamic detection range from 0 lx to ~140 klx with resolution down to 0.0042 lx/ct.

Operating Conditions:

• Supply voltage: 2.5 V to 3.6 V
• Operating temperature: -25 °C to +85 °C
• Ambient light detection range: 0 lx to ~140 klx

Absolute Maximum Ratings:

• Max continuous current: Not applicable.

Key Specs:

• Supply voltage (V DD): 2.5 V (min) to 3.6 V (max)
• Shut down current (I sd): 0.5 μA (typ, at V DD = 3.3 V)
• Operation mode current (I DD): 2 μA (typ, at V DD = 3.3 V, PSM = 11, refresh time 4100 ms)
• Highest resolution: 0.0042 lx/ct
• A/D converter resolution: 16-bit
• Flicker noise rejection: 100 Hz and 120 Hz
• Integration time settings: 25 ms to 800 ms

Features:

• Very high sensitivity
• High accuracy
• Near human eye photodiode response
• I2C bus communication interface
• Interrupt feature
• Low power consumption (0.5 μA shutdown)
• 100 Hz and 120 Hz flicker noise rejection

Applications:

• Ambient light sensing behind very dark cover glasses
• Ambient light sensing behind clear cover glasses (up to direct sunlight)

Package:

• Miniature transparent 6.8 mm by 3 mm package (4-pin)

The VEML7700 can be connected to a power supply, ranging from 2.5 V to 3.6 V. The pull-up resistors at the I 2 C bus lines may also be connected to a power supply between 1.7 V to 3.6 V, allowing them to be at the same level needed for the microcontroller.

Proposed values for the pull-up resistors should be > 1 k Ω , e.g.: 2.2 k Ω to 4.7 k Ω for the R1 and R2 resistors (at SDA and SCL).

Fig. 2 - VEML7700 Application Circuit

The VEML7700 is insensitive to any kind of disturbances, so a small ceramic capacitor at its supply pin will be enough. Only if the power supply line could be very noisy and the voltage range close to the lower limit of 2.5 V a R-C decoupler, as shown in the above circuitry, should be used.