MAX9635EDT+T Maxim Integrated Products, MAX9635EDT+T Datasheet - Page 10

• Manufacturer Part Number: MAX9635EDT+T
• Description: Optical Sensors - Board Mount Low-Power Ambient Li ght Sensor with ADC
• Manufacturer: Maxim Integrated Products

Specifications of MAX9635EDT+T

• Supply Current: 0.65 uA
• Operating Supply Voltage: 1.7 V to 3.6 V
• Maximum Power Dissipation: 953 mW
• Package / Case: uTDFN-6
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Industry’s Lowest-Power
Ambient Light Sensor with ADC
Bits in Lux Low-Byte register 0x04 give the 4 least significant bits of the mantissa byte representing the lux reading
of ambient light. Combined with the Lux High-Byte register 0x03, it extends the resolution and dynamic range of lux
measurements of the IC.
E3–E0: Exponent bits of lux reading
M7–M0: Mantissa byte of lux reading
Lux = 2
Exponent = 8xE3 + 4xE2 + 2xE1 + E0
Mantissa = 128xM7 + 64xM6 + 32xM5 + 16xM4 + 8xM3 + 4xM2 + 2xM1 + M0
Combining contents of register 0x03 and 0x04:
A code of 0000 0000 0001 calculates to be 0.045 lux.
A code of 0000 0001 0000 calculates to be 0.72 lux.
A code of 0001 0001 0001 calculates to be 0.765 lux.
A code of 1110 1111 1111 calculates to be 188,006 lux.
A code of 1110 1111 1110 calculates to be 187, 269 lux.
The Lux High-Byte 0x03 and Lux Low-Byte 0x04 register updates are internally disabled at the start of a valid address
transmission from the master. Updating reinitiates at the next valid STOP condition. This prevents erroneous readings,
in the event an update occurs between readings of registers 0x03 and 0x04.
Update of the contents of this register is internally disabled during I
between internal ADC and I
If the 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 REAPEATED START command should
be used. This ensures accurate data is obtained from the I
process).
The Upper Threshold register exponent with the four most significant bits of the mantissa sets the upper trip level for
interrupt functionality. This upper limit is relevant only if the INTE bit in the Interrupt Enable register is set. If the lux level
is greater than this light level for a time greater than that specified in the Threshold Timer register, the INTS bit in the
Interrupt Status register is set and the INT pin is pulled low.
Mantissa (UM[7:4]): Four most significant bits of mantissa upper threshold
Exponent (UE[3:0]): Exponent bits upper threshold
Upper lux threshold = 2
Exponent = 8xUE3 + 4xUE2 + 2xUE1 + UE0
Mantissa = 128xUM7 + 64xUM6 + 32xUM5 + 16xUM4 + 15
10
BIT 7
BIT 7
UE3
—
(exponent)
x mantissa x 0.045
BIT 6
BIT 6
UE2
—
(exponent)
2
C registers. Update of I
BIT 5
BIT 5
UE1
—
x mantissa x 0.045
BIT 4
BIT 4
UE0
—
2
C registers is resumed when the master sends a STOP command.
BIT 3
BIT 3
UM7
M3
2
C registers (by disabling internal updates during the read
Upper Threshold High-Byte Register 0x05
2
C read operations to ensure proper data transfer
BIT 2
BIT 2
UM6
M2
Lux Low-Byte Register 0x04
BIT 1
BIT 1
UM5
M1
BIT 0
BIT 0
UM4
M0
REGISTER
REGISTER
ADDRESS
ADDRESS
0x04
0x05