SFH 7770

2011-09-16

7

Characteristics (Ta = 25°C

)

The sensitivity range of the Proximity Sensor is typ. 100 μW/cm

data in the SFH 7770 output register are available in an approximately logarithmic scale. The advantage

of the logarithmic scale is the possibility to cover a large range of distance without changing the

sensitivity settings of the sensor. In addition the data are then approximately proportional to the distance

of an object.

When the irradiation is below 100 μW/cm², the PS output signal exhibits noise which is typically below

80 output counts (see the dashed line in the graph below).

For irradiation higher than typ. 100μW/cm², the PS output signal increases monotonically up to a value

of typ. 163.

Parameter

Symbol

Value

Unit

min.

typ.

max.

Proximity Sensor (PS)

Wavelength of max. sensitivity

S,max

850

nm

Spectral range of sensitivity (50% of S

S,50%

750 ...

1000

nm

Sensitivity range,

= 850nm

2)

E

e

0.09 ...

1.6

mW/cm²

Sensor signal (logarithmic)

2)

0 ... 254

counts

Measurement accuracy for irradiance Ee,

=850nm at Ee=500μW/cm²

- 6

+ 6

dB

LED pulse current, programmable,

( only when

V

1)

1)

DC-offset of 0.5mA has to be added to LED current consumption during LED burst

I

LED,PP

5.5

200

mA

Accuracy of LED pulse current

I

LED,PP

-20

+20

%

Mean current consumption, FREE-RUNNING

( one LED „ON“, If=100mA, t

I

act

300

μA

Modulation frequency of LED current

f

mod

667

kHz

Repeat frequency in FREE-RUNNING mode

(programmable)

t

rep

10 ...

2000

ms

Length of a single LED burst

t

burst

300

μs

Length of a measurement cycle for 3 LEDs

t

1ms

Update of register data after MCU request

t

10

ms

Sunlight suppression

50

klx