AR25-A18T

Data Sheet AR25 Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder Overview The Broadcom® AR25 is a miniature absolute encoder ASIC that is designed to cater the growing demand for space-constraint applications. Employing the advance reflective optical-encoding theory, the AR25 Series offer high position accuracy with correction algorithm, which is unattainable by the magnetic encoders. The AR25 encoder is a one-chip solution that has the flexibility to cater variable overall diameters, ranging from 30 mm to 60 mm. The AR25 also supports through-hole solutions up to 30 mm in diameter. User-programmable resolutions are from 15 bits up to 25 bits single-turn absolute outputs. In addition, the AR25 also provides differential analog Sine/Cosine or digital incremental ABIUVW signals with configurable CPRs and pole-pairs. The AR25 also comes with a state-of-the-art Auto-Calibration feature that eases customer’s integration into their end systems. The AR25 series also supports integration with Broadcom proprietary battery-less Energy Harvesting Multi-Turn (EHMT) solution. Alternatively, other multi-turn solutions like gear-based and battery back-up are also supported by a dedicated MT interface port. For power supply, the ASIC supports dual-mode operating voltages of either 3.3V or 5V, which are suitable for handheld and portable device applications. Operating temperature range is –40°C to 125°C, suitable for most industrial applications. To enhance the user system-design flexibility, the AR25 offers various protocols that are selectable by the user. Among the available protocols are Encoder Serial Link (ESL) or RS485 half-duplex protocol, SSI, BiSS-C, and SPI 4-wire. Broadcom Features               Miniature surface-mount QFN package: 6 mm (L) × 6 mm (W) × 1.05 mm (H) User-programmable absolute resolution:15 bits to 25 bits User-programmable incremental output (ABI) resolutions ranging from 1 CPR to 220 CPRs User-programmable commutation signals (UVW) ranging from 1 to 32 pole-pairs High-temperature range of –40°C to 125°C suitable for most industrial operations Dual-mode operating voltages of 3.3V and 5V, enabling handheld and portable device applications Multi-turn integration: EHMT, gear, or battery back-up Optical radius (Rop) flexibility: Blind hollow or through shaft applications Built-in line transceiver for protocol with selectable drivability strength Auto-accuracy calibration with constant speed that is one-click away Selectable communication protocols: – RS485 (2.5/5/10 Mb/s) – ESL (2.5/5/10 Mb/s) – SSI 2-wire (up to 10 MHz) – SPI 4-wire (up to 10 MHz) – BiSS-C (up to 10 MHz) External memory support up to 128 Kb Built-in temperature sensor RoHS compliance Applications    Robotic automation and engineering Factory automation and drone Medical and dentistry devices and equipment AR25-Series-DS102 March 10, 2022 AR25 Data Sheet    Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder High-accuracy portable and handheld devices Miniature motor, servo motor, and linear actuator Through-shaft motor, gear motor, and speed reducer NOTE: This product is not specifically designed or manufactured for use in any specific devices. Customers are solely responsible for determining the suitability of the product for its intended application and solely liable for all loss, damage, expense, or liability in connection with such use. Functional Description Figure 1: AR25 Block Diagram Figure 2: AR25 External Oscillator Connection Diagram Broadcom AR25-Series-DS102 2 AR25 Data Sheet Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder Figure 3: AR25 External EEPROM Connection Diagram Figure 4: AR25 External nReset Connection Diagram For more design details, refer to the AR25 Series application note (document number: AR25-Series-AN1xx). Mechanical Dimension Figure 5: Overall Package Dimension and Pinout All dimensions are given in mm. Broadcom AR25-Series-DS102 3 AR25 Data Sheet Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder . Table 1: Pinout Pin Name Function Pin Name Function 1 Port_B3 Port_C0 Port_B2 22 Port_C1 3 Port_B1 I/O protocol depends on the Port_SEL[3:0] or internal register selection. 21 2 23 Port_C2 Multi-turn I/O protocol depends on the Port_SEL[3:0] or internal register selection. 4 Port_B0 24 Port_C3 5 VDDPAD Digital power 3.3V/5V. 25 AGND Analog ground. 6 DGND Digital ground. 26 VDDA Analog power 3.3V/5V. 7 Port_A3 Port_D0 Port_A2 I/O protocol depends on the Port_SEL[3:0] or internal register selection. 27 8 28 Port_D1 29 Port_D2 Incremental and analog output depend on Port_SEL[3:0] or internal register selection. 30 Port_D3 31 nRESET Power-up delay or ASIC reset pin Protocol selection or output selection pin. 9 Port_A1 10 Port_A0 11 No Connection Open/no connection. 12 No Connection 32 Port_SEL0 13 No Connection 33 Port_SEL1 14 No Connection 34 Port_SEL2 15 No Connection 35 Port_SEL3 16 No Connection 36 Port_E0 I2C SDA external EEPROM. 17 No Connection 37 Port_E1 I2C SCL external EEPROM. 18 No Connection 38 VDDcap_1p8V Buffer capacitor 1.8V. 19 No Connection 39 VDDcap_3p3V Buffer capacitor 3.3V. 20 No Connection 40 External Oscillator 50-MHz external oscillator input. NOTE: For more details on the PORT_SEL[3:0] selection, refer to the AR25 Series application note. Refer to the AR25 Series application note for selection details. Package Marking Figure 6: Product Marking Information Broadcom AR25-Series-DS102 4 AR25 Data Sheet Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder Encoder Mounting Figure 7: Encoder Mounting Details NOTE: Broadcom The assembly of the encoder needs clean room conditions, Class 100K or better. The encoder needs to be enclosed with IP50 or higher rating enclosure. For more mechanical design requirements, refer to the AR25 Series application note. AR25-Series-DS102 5 AR25 Data Sheet Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder Recommended PCB Land Pattern Figure 8: Recommended PCB Land Pattern Details Ground via hole For more design details, refer to the AR25 Series application note. Recommended SMT Reflow Soldering Profile Figure 9: Recommended SMT Reflow Soldering Profile NOTE: Broadcom Pb-free SMT reflow soldering profile (according to JEDEC Pb-Free [J-STD-020D]). Infrared reflow and no cleaning process to prevent contamination. Peel off kapton tape on assembly process. AR25-Series-DS102 6 AR25 Data Sheet Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder Absolute Maximum Ratings Table 2: Absolute Maximum Ratings Parameter Symbol Value Storage temperature TS –40°C to 125°C Operating temperature TA –40°C to 125°C Supply voltage Vdd 7V ESD (HBM), JS-001-2014 — ±2 kV Moisture sensitive level MSL 3 (Maximum floor life = 168h) NOTE: 1. Proper operation of the encoder cannot be guaranteed if the maximum ratings are exceeded. 2. Remove Kapton tape only after SMT reflow process and just before final assembly. Take precautions to keep the encoder ASIC clean at all times. 3. Clean room conditions, Class 100K or better. 4. Some particles can be present on the surface of the encoder ASIC surface. The presence of these particles can degrade the performance of the encoder. CAUTION! Anti-static discharge precautions should be taken when handling the encoder in order to avoid damage and/or degradation induced by ESD. Electrical Specifications Table 3: Recommended Operating Conditions Parameter Symbol Min. Typ. Max. Unit Notes DC supply voltage 5V Vdd +4.5 +5.0 +5.5 V — DC supply voltage 3.3V Vdd +3.0 +3.3 +3.6 V — Ripple of supply voltage — — — 100 mVpp 100 kHz Output current per channel — — — ±5 mA Single-ended Rise time tr — 30 — ns CL = 50 pF Fall time tf — 30 — ns RL = 1.2 kΩ Ambient temperature Tamb — +25 — °C — Operational temperature TPCB –40 +25 +125 °C PCB (FR4-4 layers) temperature Storage temperature TS –40 +25 +125 °C — Humidity RH — — 85 % Temp = 40°C INC operating frequency — — — 128 kHz Velocity (rpm) × CPR/60 Below 512 CPR, spatial tolerance is ±400 μm Tangential misalignment — –500 Nominal +500 μm Radial misalignment — –400 Nominal +400 μm Gap — –500 Nominal +500 μm Encoder shaft speed SRPM — — 15000 rpm 512 CPR (AR25) Temperature sensor accuracy — — ±3 — °C At 125°C Broadcom AR25-Series-DS102 7 AR25 Data Sheet Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder Table 4: Recommended Code Wheel Characteristics Parameter Symbol Specular reflectance Rf NOTE: Min Typical Max Unit — 60% — — — — 5% Notes Reflective area Non-reflective area Characteristic based on Broadcom qualified code wheel supplier. Refer to Broadcom for qualified reflective code wheel supplier. DC Characteristics Table 5: DC Characteristics over Recommended Operating Range, Typical at 25°C Parameter Symbol Conditions Min. Typ. Max. Unit Notes VDD supply current IDD VDD = 3.3V — 65 — mA — VDD = 5.0V — 65 — mA — Absolute single-turn resolution STbits — 15 — 25a Bit — Incremental resolution — — 20 — 2nmax CPR nmax = 20 Protocol I/O drive strength IDIO VDD = 3.3V/5V 5 20 40 mA Differential driver Differential transceiver hysteresis Vhys VDD = 3.3V/5V — 100 — mV 220Ω termination Differential transceiver opening Vopen VDD = 3.3V/5V 200 — — mV Differential transceiver voltage peak-peak VPP VDD = 3.3V/5V — 2 — V Output high voltage VOH VDD = 3.3V 2.4 — — V Output low voltage VOL — 5 0.4 V Input high voltage VIH — — 2 V Input low voltage VIL 0.8 — — V Output high voltage VOH 4.4 — — V Output low voltage VOL — 5 0.5 V Input high voltage VIH — — 3.5 V Input low voltage VIL 1.5 — — V VDD = 5.0V No load No load a. Maximum number of bit able to be set in AR25. Encoder Characteristics Table 6: Incremental Encoder Characteristics over Recommended Operating Condition, at 25°C ABI Parameter Symbol Min. Typ. Max.a Unit Cycle error ΔC — — 45 edeg (electrical degree) State error ΔS — — 45 edeg Index pulse width Po — 90, 180, 270, 360 — edeg a. Maximum values represent the encoder performance across the range of recommended mounting tolerance. Broadcom AR25-Series-DS102 8 AR25 Data Sheet Smart Programmable 25-Bits Reflective Absolute Single-Turn Encoder Table 7: Commutation Characteristic over Recommended Operating Condition, at 25°C Commutation (UVW) Parameter Symbol Min. Typ. Max.a Unit Commutation accuracy (middle of channel I to channel U) ΔI –0.1 — +0.1 mdeg (mechanical degree) Commutation accuracy (channel U, V, and W) ΔUVW –0.1 — +0.1 mdeg a. Maximum values represent the encoder performance across the range of recommended mounting tolerance. Table 8: Encoder Raw Accuracy Characteristics over Recommended Operating Condition, at 25°C Parameter Raw accuracy (AR25) Accuracy_AutoCal (Speed) b Accuracy_ManualCal (Reference Encoder) c Symbol Min. Typ.a Max. Unit — — ±350 — arcsecond — — ±120 — arcsecond — — ±30 — arcsecond a. Typical values represent the encoder performance with shaft TIR < 10 μm, ɸ5.991 ~ 5.996 mm; code wheel hub inner diameter = 6.000 ~ 6.008 mm. b. Typical values represent calibration with the motor speed ripple of < 0.1%. c. Typical value represent the accuracy and repeatability when calibrated with a reference encoder having 10× higher accuracy than the AR25. (AR25 = 25 bit; Reference Encoder =