Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPhotoelectric SensorsPhoto sensor 1 pc(s) 1.7 - 3.6 Vdc (L x W x H) 2 x 2 x 0.6 mm

Industry’s Lowest-Power

Ambient Light Sensor with ADC

Bits in Lux High-Byte register 0x03 give the 4 bits of exponent E3:E0 and 4 most significant bits of the mantissa byte

M7:M4, and represent the lux reading of ambient light. The remaining 4 bits of the mantissa byte M3:M0 are in the Lux

Low-Byte register 0x04 and enhance resolution of the lux reading from the IC.

Exponent (E[3:0]): Exponent bits of the lux reading (0000 to 1110). Note: A reading of 1111 represents an overrange

condition.

Mantissa (M[7:4]): Four most significant bits of mantissa byte of the lux reading (0000 to 1111).

Lux = 2

(exponent)

x mantissa x 0.72

Exponent = 8xE3 + 4xE2 + 2xE1 + E0

Mantissa = 8xM7 + 4xM6 + 2xM5 + M4

A code of 0000 0001 calculates to be 0.72 lux.

A code of 1110 1111 calculates to be 176,947 lux.

A code of 1110 1110 calculates to be 165,151 lux.

Update of the contents of this register is internally disabled during I

C read operations to ensure proper data transfer

between internal ADC and I

C registers. Update of I

C registers is resumed when the master sends a STOP command.

If user wants to read both the Lux High-Byte register 0x03 and Lux Low-Byte register 0x04, then the master should not

send a STOP command between the reads of the two registers. Instead a Repeated START command should be used.

This ensures accurate data is obtained from the I

C registers (by disabling internal updates during the read process).

Integration Timer Bits (TIM[2:0])

The TIM[2:0] bits can be used to program the signal integration time.

In automatic mode (MANUAL = 0), integration time is automatically selected by the on-chip algorithm to be either

100ms/200ms/400ms/800ms. In manual mode, integration time can be varied by the user all the way from 6.25ms to

800ms. See Table 7.

Lux High-Byte Register 0x03

Table 7. Integration Time

TIM[2:0]

INTEGRATION

TIME (ms)

COMMENTS

000 800 This is a preferred mode for boosting low-light sensitivity.

001 400 —

010 200 —

011 100 This is a preferred mode for high-brightness applications.

100 50 Manual mode only.

101 25 Manual mode only.

110 12.5 Manual mode only.

111 6.25 Manual mode only.

BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0

ADDRESS

E3 E2 E1 E0 M7 M6 M5 M4 0x03

Maxim Integrated

MAX44009