ICHAUS IC-OV 5-bit opto encoder Datasheet

iC-OV
5-BIT OPTO ENCODER
FEATURES
APPLICATIONS
°
°
°
°
°
°
°
°
°
°
°
°
°
°
High synchronism and technical reliability due to monolithic
construction plus integrated photodiodes
Short track pitch (600 µm)
Scanning with constant-light evaluation
Photoelectric amplifier with high cut-off frequency
Current comparators with hysteresis
Current-limited TTL-compatible push-pull outputs
Adjustable LED current control for constant receive power
Integrated 40mA driver for the LED
Integrated test aid
Output of track 1 can be inverted to change the counting
direction during Gray Code scanning
Overtemperature circuit-breaker with hysteresis
Detection and fault message when the safe operating range
is exceeded, as the result of undervoltage, over-temperature
or an LED current outside the control range
Low power consumption
Scanning with constant-light
evaluation in absolute and
multiturn rotary encoders
CHIP
3.6mm × 2.9mm
BLOCK DIAGRAM
+5V
1.0
12
RSET
14k
VCC
Vref
CB
100nF
0.5
AGND
LED
11
8
1
RLED
47
ISET
1
1
DREF
LED
DDC
MONITOR
IS
LED-CURRENT CONTROL
C5
TRACK5
(see TRACK2)
TRACK4
(see TRACK2)
TRACK3
(see TRACK2)
C4
C3
2
C2
7
6
5
4
TRACK2
2
14
C1
3
5..25V
TRACK1
NINV
iC-OV
9
10
TREF
1
c2
TNRF
TEST
1
c2
THERMAL
SHUTDOWN
BLCC OVC3
NER
13
RNER
10k
LOW VOLTAGE
BIAS
GND
2
ERROR
© 2000
Rev C0
iC-Haus GmbH
Integrated Circuits
Am Kuemmerling 18, D-55294 Bodenheim
Tel +49-6135-9292-0
Fax +49-6135-9292-192
http://www.ichaus.com
iC-OV
5-BIT OPTO ENCODER
Rev C0, 2/9
DESCRIPTION
The device iC-OV is an optoelectronic encoder IC for absolute linear or angle measuring systems, e.g. glass
scales or rotary encoders.
Photodiodes, amplifiers, comparators and TTL-compatible push-pull output drivers for 5 tracks are
monolithically integrated, as well as a reference photodiode to control the LED current. The track pitch is 600
µm.
The outputs switch to high when the amplified photoelectric currents exceed a preset threshold (constant-light
evaluation). The operating point is determined by an external resistor at RSET.
This resistor also establishes the setpoint for the LED current control. The control keeps the optical receive
power constant, irrespective of the temperature or the effects of ageing. The driver stage of the LED current
control makes it possible to connect an LED with series resistor directly.
A monitoring circuit generates a fault message in the event of undervoltage, overtemperature or violation of
the LED current control range. The fault message output is busable (open collector) and low active.
Two test pins permit a complete function test (without photodiodes).
All inputs and outputs are protected against destruction by ESD. The outputs are short-circuit-proof and are
switched off in case of thermal overload.
iC-OV
5-BIT OPTO ENCODER
Rev C0, Page 3/9
CHIP LAYOUT
dimensions in µm; chip size 3.6mm x 2.9mm
PAD DESCRIPTION
Name
Function
LED
GND
C1
C2
C3
C4
C5
VCC
TREF
TNRF
ISET
AGND
NER
NINV
LED Current Control Output
Ground
Track 1 Push-Pull Output
Track 2 Push-Pull Output
Track 3 Push-Pull Output
Track 4 Push-Pull Output
Track 5 Push-Pull Output
+5V Supply Voltage
Test Aid for photodiode DREF
Test Aid for tracks 1 to 5 and compensation DDC
LED Current Control Setup
Reference Ground for ISET circuitry
Error Message Output, low active
Track 1 Invert Mode Input, low active
iC-OV
5-BIT OPTO ENCODER
Rev C0, Page 4/9
ABSOLUTE MAXIMUM RATINGS
Values beyond which damage may occur; device operation is not guaranteed.
Item
Symbol
Parameter
G001 VCC
Supply Voltage
G002 V(C)
Voltage at Outputs C1..5
G003 I(C)
Current in Outputs C1..5
G004 I(TNRF)
Conditions
Fig.
Unit
Min.
Max.
0
7
V
0
VCC
V
-3
3
mA
Current in TNRF
-2
1
mA
G005 I(TREF)
Current in TREF
-2
1
mA
G006 I(ISET)
Current in ISET
-2
2
mA
G007 I(AGND)
Current in AGND
-5
5
mA
G008 I(LED)
Current in LED to GND
0
50
mA
G009 I(LED)
Current in LED
0
3
mA
G010 V(NER)
Voltage at NER
0
30
V
G011 I(NINV)
Current in NINV
-2
2
mA
TG1 Tj
Junction Temperature
-30
125
EC
TG2 Ts
Storage Temperature
V(C)< 0V or V(C)> VCC
V(LED)> VCC
see package specification
THERMAL DATA
Operating Conditions: VCC= 5V ±10%
Item
Symbol
Parameter
Conditions
Ta
Operating Ambient Temperature
Range
see package specification
Fig.
Unit
Min.
T1
All voltages are referenced to ground unless otherwise noted.
All currents into the device pins are positive; all currents out of the device pins are negative.
Typ.
Max.
iC-OV
5-BIT OPTO ENCODER
Rev C0, Page 5/9
ELECTRICAL CHARACTERISTICS
Operating Conditions:
VCC= 5V ±10%, Tj= -25..125EC, unless otherwise noted
Item
Symbol
Parameter
Conditions
Tj
EC
Fig.
Unit
Min.
Typ.
Max.
Total Device
001 VCC
Permissible Supply Voltage
Range
002 I(VCC)
Supply Current in VCC,
Outputs C1..5 hi
closed LED Control:
R(ISET/AGND)= 14kS,
I(LED). 10mA, NER= hi;
I(C1..5)= 0, I(D1..5)= 80nA
003 I(VCC)
Supply Current in VCC,
Outputs C1..5 lo
closed LED Control:
R(ISET/AGND)= 14kS,
I(LED). 10mA, NER= hi;
I(C1..5)= 0, I(D1..5)# 8nA
004 fo
Cut-off Frequency,
tracks 1..5
sinusoidal waveform,
I(D1..5)= 8..80nA, I(DREF)= 80nA
Delay Skew C1..5
rectangular waveform,
I(D1..5)= 8..80nA, I(DREF)= 80nA
005
)tp()
4.5
5.5
V
7
13
mA
8
15
mA
200
kHz
0.5
µs
Photodiodes D1..5, DREF
006 S(8)max
007
8ar
Spectral Sensitivity
Spectral Application Range
8= 850nm
Se(8ar)= 0.1×S(8)max
0.5
500
A/W
1050
nm
Photodiodes D1..5 with Amplifiers
101 Aph(D)
Radiant Sensitive Area
102 CM()
Common Mode referred to
Reference Photodiode DREF
0.2 × 0.1
mm²
0.85
1
1.15
8
12
16
%
1.4
V
V
0.4
0.4
0.4
0.5
V
V
V
V
9
mA
mA
10
mA
mA
Difference Comparators, tracks 1..5
201 Hys
Hysteresis referred to
[I(D) + IS] /2
I(D1..5)= 0..80nA
Push-Pull Outputs C1..5
301 Vs()hi
302 Vs()lo
303 Isc()hi
304 Isc()lo
Saturation Voltage hi
Saturation Voltage lo
Short-Circuit Current hi
Short-Circuit Current lo
Vs()hi= VCC-V(C);
I()= -1.6mA
I()= 1.6mA
27
1.1
-25
27
85
125
0.25
V()= 0..2.8V
27
4
27
5
V()= 2V..VCC
305 tr()
Rise Time
C: lo6hi; CL= 30pF
80
260
ns
306 tf()
Fall Time
C: hi6lo; CL= 30pF
40
100
ns
307 Vc()hi
Clamp Voltage hi
Vc()hi= V(C)-VCC;
I()= 3mA
0.4
1.5
V
308 Vc()lo
Clamp Spannung lo
I()= -3mA
-1.5
-0.4
V
Test Aid TNRF, TREF
401 CR()
Current Ratio
I(TNRF)/I(D1..5)
test aid active,
I()= 2..200µA
200
550
800
402 CR()
Current Ratio
I(TNRF)/I(DDC),
I(TREF)/I(DREF)
test aid active,
I()= 2..200µA
400
1100
1600
iC-OV
5-BIT OPTO ENCODER
Rev C0, Page 6/9
ELECTRICAL CHARACTERISTICS
Operating Conditions:
VCC= 5V ±10%, Tj= -25..125EC, unless otherwise noted
Item
Symbol
Parameter
Conditions
Tj
EC
Fig.
Unit
Min.
Typ.
Max.
Test Aid TNRF, TREF (continued)
403 It()
404 V()on
2
Pull-Down Current
(Test Aid Turn-on Threshold)
V()= 0.5V
Turn-on Voltage
test aid active; I(TNRF)= 2..200µA -25
27
and I(TREF)= 100µA, or
85
I(TNRF)= 100µA and
125
I(TREF)= 2..200µA
150
µA
µA
µA
µA
µA
2.7
2.4
2.1
1.9
V
V
V
V
14
17
21
23
-25
27
85
125
1.9
1.6
1.3
1.1
2.4
2.1
1.8
1.6
LED Current Control with Reference Photodiode DREF
501 Aph()
Radiant Sensitive Area DREF
502 I(DREF)
Permis. Photocurrent at DREF
503 I(LED)
Permis. Driver Current in LED
504 Vs(LED) Saturation Voltage at LED
0.2 × 0.1
10
0
mm²
200
nA
40
mA
I(LED)= 40mA, I(ISET)>10µA,
I(DREF)=0
0.4
0.9
1.4
V
1.14
1.22
1.28
V
1.3
mA
mA
505 V(ISET)
Voltage at ISET
I(ISET)= -100..-10µA
506 Isc()
Short-Circuit Current in ISET
V(ISET)= 0
507 CR()
Current Ratio
I(ISET)/I(DREF)
closed LED control,
I(DREF)= 20..200nA
720
1080
1820
508 CR()
Current Ratio
I(ISET)/I(DREF)
closed LED control,
I(DREF)= 60..120nA
840
1080
1440
509 Vc()hi
Clamp Voltage hi at ISET, LED
VCC= 0, I()= 3mA
0.4
1.5
V
510 Vc()lo
Clamp Voltage lo at ISET, LED
VCC= 0, I()= -3mA
-1.5
-0.4
V
0.5
1
V
27
0.5
Inverting Mode Input NINV
601 Vt()
Threshold Voltage hi
602 Ipu()
Pull-Up Current
V(NINV)= 0V, I(D1)< I(DREF)
80
µA
603 Ipu()
Pull-Up Current
V(NINV)= 0V, I(D1)> I(DREF)
20
µA
604 Vc()hi
Clamp Voltage hi
Vc()hi= V(NINV)-VCC; I()= 3mA
0.4
1.5
V
605 Vc()lo
Clamp Voltage lo
I()= -3mA
-1.5
-0.4
V
EC
EC
Bias, Temperature and Supply Monitor
701 Toff
Thermal Shutdown Threshold
702 Thys
Thermal Shutdown Hysteresis
Thys= Toff-Ton
127
138
150
5
9
12
703 VCCon
Turn-on Threshold VCC
3.6
3.9
4.4
V
704 VCCoff
Undervoltage Threshold at VCC
decreasing Supply VCC
3.4
3.8
4.3
V
705 VCChys
Hysteresis
VCChys= VCCon-VCCoff
40
100
250
mV
0.4
0.4
0.4
0.5
V
V
V
V
8
mA
mA
10
µA
µA
706 Vs(NER) Saturation Voltage lo at NER
707 Isc(NER) Short-Circuit Current lo in NER
708 I0(NER)
Collector Off-State Current
in NER
I()= 1.6mA
-25
27
85
125
0.3
V()= 2V..VCC
27
5
27
0.1
NER: off, V()= 25V
iC-OV
5-BIT OPTO ENCODER
Rev C0, Page 7/9
DESCRIPTION OF FUNCTIONS
LED Current Control
The integrated LED current control with driver stage keeps the photoelectric current of the reference photodiode
DREF constant. This compensates for ageing, dirt and the decline in LED efficiency as the temperature rises.
Fig. 1: LED Current Control and Monitor
The photoelectric current of the reference DREF and the dark current of compensation diode DDC are amplified
in the current control. The amplified currents are subtracted from one another, yielding the actual value for the
driver’s negative input to trigger the LED.
At the same time, resistor RSET at the pin ISET sets the setpoint for the positive input of the driver - the voltage
at pin ISET is kept at a constant approx. 1.22V.
If there is an optical feedback loop from the LED to reference photodiode DREF, the driver changes the current
through the LED until the actual value at the negative input corresponds to the setpoint at the positive input.
The photoelectric current through the reference DREF and, therefore, the illuminance for the system as a whole
are kept constant. A monitor circuit detects the violation of the control range and indicates this via the fault
message circuit (block: Error).
The series resistor RLED connected in series to the LED limits the current through the diode and establishes the
operating limit of the control.
The optical feedback between LED and reference photodiode should suffice to yield an LED current of less than
8mA at room temperature. The power driver then also possesses sufficient current reserve to correct the
dropping efficiency of the LED at high temperatures.
iC-OV
5-BIT OPTO ENCODER
Rev C0, Page 8/9
Tracks 1..5
The threshold IS of the current comparators for tracks C1 to C5 is determined by the resistor RSET and is about
0.5 x ISET. The threshold is supplemented by the amplified current of compensation diode DDC to compensate
for the dark currents of photodiodes D1 to D5 and the amplifier input currents. The hysteresis of the current
comparators enhances the interference immunity.
Track 1 can be inverted by connecting pin NINV to ground (GND). If the pin remains open, the internal pull-up
current source generates a high level. When the Gray Code is used, inverting the MSB track is the equivalent to
reversing the movement.
Fault message in case of overtemperature or undervoltage
When the chip temperature is too high or the voltage too low, the push-pull output stages are switched to a
high-impedance state and the error state is signalled to the message circuit (block: Error). Both monitoring
circuits operate with hysteresis; NER= low remains until the cause of the error has been eliminated.
Violating the limits of the LED current control range also generates a low signal at the open collector output NER.
APPLICATIONS INFORMATION
Wiring the Test Aid
To activate the test aid integrated into the iC-OV, the current threshold defined in the Electrical Characteristics
No. 403 must be exceeded at both pins TREF and TNRF. This activates the testing aid which does not switch
back off until the current drops below approx. 1µA.
A clamping circuit as per Fig. 2 also prevents a brief drop below the cut-off threshold. A changeover switch can
be used to reverse the output polarity of the iC-OV.
Fig. 2: Wiring the testing aid
iC-OV
5-BIT OPTO ENCODER
Rev C0, Page 9/9
ORDERING INFORMATION
Type
Package
Order designation
iC-OV
iC-OV
BLCC OVC3
iC-OV Chip
iC-OV BLCC OVC3
For information about prices, terms of delivery, options for other case types, etc., please contact:
iC-Haus GmbH
Am Kuemmerling 18
D-55294 Bodenheim
GERMANY
Tel (+49)6135-9292-0
Fax (+49)6135-9292-192
http://www.ichaus.com
This specification is for a newly developed product. iC-Haus therefore reserves the right to modify data without further notice. Please contact
us to ascertain the current data. The data specified is intended solely for the purpose of product description and is not to be deemed
guaranteed in a legal sense. Any claims for damage against us - regardless of the legal basis - are excluded unless we are guilty of
premeditation or gross negligence.
We do not assume any guarantee that the specified circuits or procedures are free of copyrights of third parties.
Copying - even as an excerpt - is only permitted with the approval of the publisher and precise reference to source.
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