iC-LV

5-BIT OPTO ENCODER

Rev A3, Page 2/12

D0

SCLK

VDD

LVCC

SYNM1

SEEN

SYNM0

SERIN

SOUT

GND

AGND

LED

NINV

MODE

TEST

RSET

NERR

NDIR

VCCA

D3

D1

D2

D4

DREF

RC

DESCRIPTION

iC-LV is an optoelectronic encoder IC for absolute linear and angle measuring systems such as glass scales

and shaft encoders, for example. Photosensors, amplifiers and comparators for 5 tracks at a pitch of 600 m

and a reference photosensor operating the LED power control are monolithically integrated on the chip.

The internal comparator outputs switch to high when the amplified photocurrents exceed a given threshold

(constant light evaluation). This threshold can be adjusted using an external resistor at RSET; alternatively,

if RSET is not wired an internal resistor is used.

The internal or external resistor also establishes a setpoint for the LED current control which irrespective of

temperature or the effects of aging keeps the optical receive power constant. A driver stage enables either a

transmitting LED with a series resistor to be directly connected to the device or operates an external transistor

to generate higher currents.

Track information can be read out in parallel (either in Gray or binary code) or serially via an SSI protocol.

Here, any number of iC-LVs can be cascaded and synchronized with one another; data is then output as a

binary word (requiring Gray code discs).

A watchdog generates an alarm message via the error output if the LED current control range is exceeded.

The open-drain error output can be wired to a bus; the signal is then low active. The serial data output can

also be complemented by the error bit.

All inputs and outputs are protected against destruction by ESD. Two different test modes can be selected by

pin and permit a complete test of functions with the exception of the photosensors.

CHIP LAYOUT

PAD DESCRIPTION

Name

Function

RC

RC Network for SSI Monoflop (wiring is optional)

VCCA

+4...+5.5 V Analog Supply Voltage

VDD

+4...+5.5 V Digital Supply Voltage

LVCC

+4...+5.5 V LED Driver Supply Voltage

NINV

Bit-wise Inversion Input (low active)

MODE

Operating Mode Selection Input

TEST

Test Mode Enable Input (high active)

RSET

LED Power Control Adjustment (wiring is optional)

NERR

Error Output (low active)

NDIR

Reversal of Rotation Dir. Input (low active)

SEEN

Serial Error Bit Enable Input (high active)

SYNM1

Synchronisation Mode Input / Data Output D0

SYNM0

Synchronisation Mode Input / Data Output D1

SCLK

Clock Input (SSI) / Data Output D2

SERIN

Serial Data Input (SSI) / Data Output D3

SOUT

Serial Data Output (SSI) / Data Output D4

GND

Digital Ground

AGND

Analog Ground

LED

LED Power Control Output (high-side current source)