IC-OV

iC-OV 5-BIT OPTO ENCODER FEATURES ° ° ° ° ° ° ° ° ° ° ° ° ° 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 APPLICATIONS ° 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 0.5 LED 8 CB 100nF Vref AGND 1 RLED 47 11 ISET 1 DREF LED 1 DDC IS MONITOR LED-CURRENT CONTROL C5 TRACK5 (see TRACK2) 7 C4 TRACK4 (see TRACK2) 6 C3 TRACK3 (see TRACK2) 5 2 C2 TRACK2 4 2 C1 TRACK1 3 14 5..25V NINV iC-OV 9 10 TREF TNRF 1 c2 1 c2 THERMAL SHUTDOWN LOW VOLTAGE BIAS BLCC OVC3 NER GND ERROR 13 2 RNER 10k TEST © 2000 iC-Haus GmbH Integrated Circuits Am Kuemmerling 18, D-55294 Bodenheim Rev C0 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 LED GND C1 C2 C3 C4 C5 VCC TREF TNRF ISET AGND NER NINV Function 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 Conditions Fig. Min. G001 VCC G002 V(C) G003 I(C) G004 I(TNRF) G005 I(TREF) G006 I(ISET) G007 I(AGND) G008 I(LED) G009 I(LED) G010 V(NER) G011 I(NINV) TG1 Tj TG2 Ts Supply Voltage Voltage at Outputs C1..5 Current in Outputs C1..5 Current in TNRF Current in TREF Current in ISET Current in AGND Current in LED to GND Current in LED Voltage at NER Current in NINV Junction Temperature Storage Temperature see package specification V(LED)> VCC V(C)< 0V or V(C)> VCC 0 0 -3 -2 -2 -2 -5 0 0 0 -2 -30 Max. 7 VCC 3 1 1 2 5 50 3 30 2 125 V V mA mA mA mA mA mA mA V mA Unit EC THERMAL DATA Operating Conditions: VCC= 5V ±10% Item Symbol Parameter Conditions Fig. Min. T1 Ta Operating Ambient Temperature Range see package specification Typ. Max. Unit 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. 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 Fig. Min. Typ. Max. Unit EC Total Device 001 VCC 002 I(VCC) Permissible Supply Voltage Range 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 closed LED Control: R(ISET/AGND)= 14kS, I(LED). 10mA, NER= hi; I(C1..5)= 0, I(D1..5)# 8nA sinusoidal waveform, I(D1..5)= 8..80nA, I(DREF)= 80nA rectangular waveform, I(D1..5)= 8..80nA, I(DREF)= 80nA 4.5 7 5.5 13 V mA 003 I(VCC) Supply Current in VCC, Outputs C1..5 lo 8 15 mA 004 fo 005 Cut-off Frequency, tracks 1..5 Delay Skew C1..5 200 0.5 kHz µs )tp() Photodiodes D1..5, DREF 006 S(8)max 007 Spectral Sensitivity Spectral Application Range 8ar 8= 850nm Se(8ar)= 0.1×S(8)max 0.5 500 1050 A/W nm Photodiodes D1..5 with Amplifiers 101 Aph(D) 102 CM() Radiant Sensitive Area Common Mode referred to Reference Photodiode DREF 0.85 0.2 × 0.1 1 1.15 mm² Difference Comparators, tracks 1..5 201 Hys Hysteresis referred to [I(D) + IS] /2 I(D1..5)= 0..80nA 8 12 16 % Push-Pull Outputs C1..5 301 Vs()hi 302 Vs()lo Saturation Voltage hi Saturation Voltage lo Vs()hi= VCC-V(C); I()= -1.6mA I()= 1.6mA 1.4 27 -25 27 85 125 27 304 Isc()lo 305 tr() 306 tf() 307 Vc()hi 308 Vc()lo Short-Circuit Current lo Rise Time Fall Time Clamp Voltage hi Clamp Spannung lo V()= 2V..VCC 27 C: lo6hi; CL= 30pF C: hi6lo; CL= 30pF Vc()hi= V(C)-VCC; I()= 3mA I()= -3mA 0.4 -1.5 5 80 40 260 100 1.5 -0.4 1.1 0.25 0.4 0.4 0.4 0.5 9 4 10 V V V V V V mA mA mA mA ns ns V V 303 Isc()hi Short-Circuit Current hi V()= 0..2.8V Test Aid TNRF, TREF 401 CR() 402 CR() Current Ratio I(TNRF)/I(D1..5) Current Ratio I(TNRF)/I(DDC), I(TREF)/I(DREF) test aid active, I()= 2..200µA test aid active, I()= 2..200µA 200 400 550 1100 800 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 Fig. Min. Typ. Max. Unit EC Test Aid TNRF, TREF (continued) 403 It() Pull-Down Current (Test Aid Turn-on Threshold) V()= 0.5V -25 27 85 125 test aid active; I(TNRF)= 2..200µA -25 27 and I(TREF)= 100µA, or 85 I(TNRF)= 100µA and 125 I(TREF)= 2..200µA 2 14 17 21 23 1.9 1.6 1.3 1.1 2.4 2.1 1.8 1.6 150 µA µA µA µA µA V V V V 404 V()on Turn-on Voltage 2.7 2.4 2.1 1.9 LED Current Control with Reference Photodiode DREF 501 Aph() 502 I(DREF) 503 I(LED) Radiant Sensitive Area DREF Permis. Photocurrent at DREF Permis. Driver Current in LED I(LED)= 40mA, I(ISET)>10µA, I(DREF)=0 I(ISET)= -100..-10µA V(ISET)= 0 27 507 CR() 508 CR() 509 Vc()hi 510 Vc()lo Current Ratio I(ISET)/I(DREF) Current Ratio I(ISET)/I(DREF) Clamp Voltage hi at ISET, LED Clamp Voltage lo at ISET, LED closed LED control, I(DREF)= 20..200nA closed LED control, I(DREF)= 60..120nA VCC= 0, I()= 3mA VCC= 0, I()= -3mA 720 840 0.4 -1.5 0.5 1080 1080 1820 1440 1.5 -0.4 V V 10 0 0.4 1.14 0.9 1.22 0.2 × 0.1 200 40 1.4 1.28 1.3 mm² nA mA V V mA mA 504 Vs(LED) Saturation Voltage at LED 505 V(ISET) 506 Isc() Voltage at ISET Short-Circuit Current in ISET Inverting Mode Input NINV 601 Vt() 602 Ipu() 603 Ipu() 604 Vc()hi 605 Vc()lo Threshold Voltage hi Pull-Up Current Pull-Up Current Clamp Voltage hi Clamp Voltage lo V(NINV)= 0V, I(D1)< I(DREF) V(NINV)= 0V, I(D1)> I(DREF) Vc()hi= V(NINV)-VCC; I()= 3mA I()= -3mA 0.4 -1.5 0.5 80 20 1.5 -0.4 1 V µA µA V V Bias, Temperature and Supply Monitor 701 Toff 702 Thys 703 VCCon 704 VCCoff 705 VCChys Thermal Shutdown Threshold Thermal Shutdown Hysteresis Turn-on Threshold VCC Undervoltage Threshold at VCC Hysteresis decreasing Supply VCC VCChys= VCCon-VCCoff I()= 1.6mA -25 27 85 125 27 708 I0(NER) Collector Off-State Current in NER NER: off, V()= 25V 27 0.1 Thys= Toff-Ton 127 5 3.6 3.4 40 138 9 3.9 3.8 100 0.3 150 12 4.4 4.3 250 0.4 0.4 0.4 0.5 8 5 10 EC EC V V mV V V V V mA mA µA µA 706 Vs(NER) Saturation Voltage lo at NER 707 Isc(NER) Short-Circuit Current lo in NER V()= 2V..VCC 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 iC-OV iC-OV Package BLCC OVC3 Order designation 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.