Features • • • • • • Temperature and Supply Voltage Compensated Flashing Frequency Frequency Doubling Indicates Lamp Outage Relay Driver Output with High Current Carrying Capacity and Low Saturation Voltage Minimum Lamp Load for Flasher Operation: ≥ 1W Very Low Susceptibility to EMI Protection According to ISO/TR 7637/1 Level 4 Flasher IC with 30-mΩ Shunt U643B 1. Description The bipolar integrated circuit U643B is used in relay-controlled automotive flashers where a high-level EMC is required. Lamp outage is indicated by frequency doubling during hazard warning as well as direction mode. Rev. 4727B–AUTO–09/05 2. Block Diagram Figure 2-1. Car Flasher Application Circuit, Resistor R1 and R2: 0.25W; R4 for Protection Against Continuous Reversed Polarity: 0.5W + VS + 49 6 C1 2 R3 Shunt Measuring comparator K 1 4 K1 V 6-81 mV 20 kΩ 30 mΩ 5 kΩ 7 K2 Pulse generator R1 3 49 a-Comparator K 2 Relay 20 kΩ 49 a-Comparator K 3 8 R2 49 a K3 1.5...2.2 kΩ 5 23 V 20 kΩ 5 kΩ IC Ground 1 R4 470 Ω 5 W 21 W 21 W 21 W 21 W 5 W Indicator lamps GND - 31 2 U643B 4727B–AUTO–09/05 U643B 3. Pin Configuration Figure 3-1. Pinning GND 1 8 SI VS 2 7 LD REL 3 6 VS OSC 4 5 OSC U643B Table 3-1. Pin Description Pin Symbol Function 1 GND 2 VS 3 REL Relay driver 4 OSC C1 Oscillator 5 OSC 6 VS Supply voltage VS 7 LD Lamp failure detection 8 SI Start input (49a) IC ground Supply voltage VS R1 Oscillator 3 4727B–AUTO–09/05 4. Functional Description 4.1 Pin 1, GND The U643B is protected against damage in case of battery reversal via resistor R4 to ground (–31). An integrated protection circuit together with external resistances R2 and R4 limits the current pulses in the IC. 4.2 Pin 2, Supply Voltage, VS Power The arrangement of the supply connections to pin 2 must be so as to ensure that on the connection printed circuit board (PCB), the resistance of VS to pin 6 is lower than that to pin 2. 4.3 Pin 3, Relay Control Output (Driver) The relay control output is a high-side driver with a low saturation voltage. It is capable of driving a typical automotive relay with a minimum coil resistance of 60Ω. 4.4 Pin 4 and 5, Oscillator The flashing frequency, f1, is determined by the R1C1 components as given by the formula below (see Figure 2-1 on page 2): 1 f 1 ≈ ------------------------------------- Hz R 1 × C 1 × 1.5 where C1 ≤47 µF, R1 = 6.8 kΩ to 510 kΩ In case of a lamp outage (see pin 7) the oscillator frequency is switched to the lamp outage frequency f2 with f2 ≈ 2.2 × f1. Duty cycle in normal flashing mode: 50% Duty cycle in lamp outage mode: 40% (bright phase) 4.5 Pin 6, Supply Voltage, Sense For accurate monitoring via the shunt resistor, a minimized layer resistance from point VS/shunt to pin 6 is recommended. 4 U643B 4727B–AUTO–09/05 U643B 4.6 Pin 7, Lamp Outage Detection The lamp current is monitored via an external shunt resistor R3 and an internal comparator K1 with its reference voltage of typically 81 mV (VS = 12V). The outage of one lamp is detected according to the following calculation: Nominal current of 1 lamp: 21W / (VS = 12V): Ilamp = 1.75A Nominal current of 2 lamps: 2 × 21W / (VS = 12V): Ilamp = 3.5A. The detection threshold should be set in the middle of the current range: Ioutage ≈ 2.7A Thus, the shunt resistor is calculated as: R3 = VT (K1) / Ioutage R3 = 81 mV/2.7A = 30 mΩ Comparator K1's reference voltage is matched to the characteristics of filament lamps (see Control Signal Threshold in “Electrical Characteristics” on page 6). The combination of shunt resistor and resistance of wire harness prevents pin 7 from a too high voltage in the case of shorted lamps. 4.7 Pin 8, Start Input Start condition for flashing: the voltage at pin 8 has to be below K3 threshold (flasher switch closed). Humidity and dirt may decrease the resistance between 49a and GND. If this leakage resistance is > 5 kΩ, the IC still remains in the OFF condition. In this case the voltage at pin 8 is between the thresholds of comparators K2 and K3. During the bright phase the voltage at pin 8 is above the K2 threshold, during the dark phase it is below the K3 threshold. For proper start conditions a minimum lamp wattage of 1W is required. 5 4727B–AUTO–09/05 5. Absolute Maximum Ratings Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Reference point pin 1 Parameters Symbol Value Unit Pins 2 and 6 VS 16.5 V tP = 0.1 ms tP = 300 ms tP = 300 ms Pins 2 and 6 Pins 2 and 6 Pin 8 IFSM IFSM IFSM 1.5 1.0 50 A A mA Output current Pin 3 IO 0.3 A DIP 8 SO8 DIP 8 SO8 Ptot Ptot Ptot Ptot 420 340 690 560 mW mW mW mW Supply voltage Surge Forward Current Power Dissipation Tamb = 95°C Tamb = 60°C Junction temperature TJ 150 °C Ambient temperature range Tamb –40 to +95 °C Storage temperature range Tstg –55 to +150 °C Symbol Value Unit RthJA RthJA 110 160 K/W K/W 6. Thermal Resistance Parameters Junction ambient DIP8 SO8 7. Electrical Characteristics Typical values under normal operation in application circuit (see Figure 2-1 on page 2), VS (+49, pin 2 and 6) = 12V. Reference point ground (–31), Tamb = 25°C, unless otherwise specified. Parameters Test Conditions Symbol Supply voltage range Pins 2 and 6 VS (+49) 9 to 15 Supply current Pins 2 and 6 Dark phase Bright phase IS IS 4.5 7.0 Relay output: Saturation voltage Pin 3 IO = 150 mA, VS = 9V with resistance = 60Ω Reverse current Start delay First bright phase Frequency tolerance Max. Unit V 8 11 mA mA 1.0 0.1 V mA 10 ms δf1 –5 +5 % ∆f1 ∆f2 47 37 53 45 % % f2 2.15 f1 2.3 f1 Hz 85 66 76 91 71 81 97 76 87 mV mV mV 4 5 kΩ ton Basic frequency f1 Control frequency f2 Frequency increase Lamp outage Control signal threshold VS = 15V, pin 7 VS = 9V, pin 7 VS = 12V, pin 7 VR3 VR3 VR3 Leakage resistance 49a to GND RP 6 Typ. VO IO Bright period Lamp load Min. PL 1 W U643B 4727B–AUTO–09/05 U643B 8. Ordering Information Extended Type Number Package Remarks U643B-MY DIP8 Pb-free U643B-MFPY SO8 Tubed, Pb-free U643B-MFPG3Y SO8 Taped and reeled, Pb-free 9. Package Information 9.1 DIP8 7 4727B–AUTO–09/05 9.2 SO8 Package SO8 Dimensions in mm 5.2 4.8 5.00 4.85 3.7 1.4 0.25 0.10 0.4 1.27 0.2 3.8 6.15 5.85 3.81 8 5 technical drawings according to DIN specifications 1 4 10. Revision History Please note that the following page numbers referred to in this section refer to the specific revision mentioned, not to this document. 8 Revision No. History 4727B-AUTO-09/05 • • • • Put datasheet in a new template Updated text to new style guide First page: Pb-free logo added Page 6: Ordering Information changed U643B 4727B–AUTO–09/05 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Regional Headquarters Europe Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500 Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 Microcontrollers 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France Tel: (33) 2-40-18-18-18 Fax: (33) 2-40-18-19-60 ASIC/ASSP/Smart Cards 1150 East Cheyenne Mtn. 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