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iC-LSHB

INCREMENTAL PHOTOSENSOR ARRAY

Rev B1, Page 2/8

DESCRIPTION

iC-LSHB is an optical sensor IC with 6 integrated

photodiodes whose signal currents are converted

into output voltages by low-noise transimpedance

amplifiers.

The IC is well suited for the operation of interpolation

circuits for linear or rotary incremental encoders with

an index signal. iC-LSHB thus has a shamrock-style

sensor layout of four photodiodes, each with an ac-

tive area of 800 µm x 330 µm. Both a positive and

negative sine signal and a positive and negative co-

sine signal are generated from a single shared code

track. The signal amplifier layout ensures excellent

paired channel matching, reducing signal differences

to an absolute minimum.

Two separate photodiodes, with active areas of 1720

µm x 150 µm apiece, are employed for the differential

scanning of the index track and to generate the zero

signal.

The spectral sensitivity ranges from visible to near

infrared light, with the maximum sensitivity close to a

wavelength of 680 nm.

Due to a high transimpedance gain of typically 4 MΩ,

signal voltages of several hundred millivolts are ob-

tained at low illumination levels.

An output signal

amplitude of 1 V is typical in low light conditions,

for instance when iC-LSHB is illuminated at only

A threefold intensity is sufficient when using iC-LSHB

for encoder applications with typical disc and mask

codes.

Therefore, a relatively low LED current is

enough to operate the sensor, proving beneficial to

the life expectancy of the LED at high operating tem-

peratures.

iC-LSHB is suitable for on-chip or LED-end mounting

of the grating (reticle), so that the period count, signal

waveform, phase shift and index marker code can be

selected with flexibility.

PACKAGES

PAD LAYOUT (2.88 mm x 2.04 mm)

PAD FUNCTIONS

No. Name Function

1 VCC

+4.5..5.5 V Supply Voltage

2 PZ

Zero Signal (Index)

3 NZ

Reference Voltage Output

4 GND

Ground

5 NCOS Cosine -

6 PCOS Cosine +

7 NSIN

Sine -

8 PSIN

Sine +

Notes: All outputs supply analog volt-

ages.

Dimension G4 is the reference radius of

the chip center.