iC-LV
5-BIT OPTO ENCODER
Rev A3, Page 2/12
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 Network for SSI Monoflop (wiring is optional)
+4...+5.5 V Analog Supply Voltage
+4...+5.5 V Digital Supply Voltage
+4...+5.5 V LED Driver Supply Voltage
Bit-wise Inversion Input (low active)
Operating Mode Selection Input
Test Mode Enable Input (high active)
LED Power Control Adjustment (wiring is optional)
Error Output (low active)
Reversal of Rotation Dir. Input (low active)
RC
VCCA
VDD
LVCC
NINV
MODE
D0
RC
SEEN
SYNM1
VCCA
VDD
LVCC
NINV
MODE
TEST
RSET
NERR
NDIR
D1
SYNM0
D2
SCLK
SERIN
D3
SOUT
D4
GND
AGND
LED
TEST
RSET
NERR
NDIR
SEEN
SYNM1
SYNM0
SCLK
SERIN
SOUT
GND
AGND
LED
Serial Error Bit Enable Input (high active)
Synchronisation Mode Input / Data Output D0
Synchronisation Mode Input / Data Output D1
Clock Input (SSI) / Data Output D2
Serial Data Input (SSI) / Data Output D3
Serial Data Output (SSI) / Data Output D4
Digital Ground
Analog Ground
LED Power Control Output (high-side current source)
DREF
ICHAUS [ IC-HAUS GMBH ]
