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| U426B Infrared Driver Description The U426B is an IR-driver IC for IR data communication. The circuit contains a programmable constant current source (DRV) to drive the IRED. The current is programmed by an external resistor (RS). With the internal comparator (COMP) an external voltage can be monitored. The low-power standby mode, controlled by means of the WAKE input, makes the circuit well suited for battery-powered systems. Features D D D D D Programmable constant current 200 mA to 1.2 A Signal frequency up to 500 kHz Low-power standby mode Internal voltage comparator Wide voltage range 2.4 V to 12 V Applications D Keyless entry systems D Remote control D Wireless data communication Ordering Information Extended Type Number U426B-FP Package SO8 Remarks VBatt U426B Controller DATA WAKE MON-O RS MON-I DRV IRED COMP 95 9947 Figure 1. Block diagram for an IR transmitter Rev. A2, 15-Oct-98 1 (6) U426B Pin Description VS 1 8 GND Pin 1 8 2 7 Symbol VS GND DATA IRED Function Supply voltage Circuit ground Data input for switching the IRED output current on and off IR-LED output; when the data input is high, this output supplies the IR LED with the constant current The resistor at this pin adjusts the IRED output current Voltage monitor input of the internal comparator Voltage monitor output. This open collector output is active when the voltage at MON-I is below the internal reference V3 = 525 mV typ. WAKE input. When being LOW, the circuit is in standby mode. A high level activates the circuit DATA 2 7 IRED U426B MON-I 3 6 SHUNT 6 3 4 95 9877 SHUNT MON-I MON-O MON-O 4 5 WAKE Figure 2. Pinning 5 WAKE Block Diagram VS IRED + - WAKE Power supply VShunt = 150 mV typ. DRV SHUNT DATA MON-O MON-I - + V3 = 525 mV typ. COMP GND COMP Monitoring comparator DRV IRED constant current driver Figure 3. Block diagram 95 9948 2 (6) Rev. A2, 15-Oct-98 U426B Constant Current Driver (DRV) The constant current driver converts the incoming data pulses into adequate constant current pulses. A high level applied to the data input causes a constant current flow through the IR diode connected to the IRED output. This current can be programmed via the external resistor (RS). To calculate the output current, use the following formula: I RED against voltages above 13 V. The internal supply voltage can be switched on/off with a high/low level at the WAKE input. Setting WAKE to low level switches the circuit from busy to standby mode which results in a very low current consumption (2 mA). Every change between busy and standby mode needs a latency of up to 1 ms. Data transmission and voltage monitoring only takes place while WAKE remains high. + 150 mV RS Monitoring Comparator (COMP) The monitoring comparator compares the voltage at Pin MON-I to an internal reference voltage of V3 = 525 mV typ. The open collector output transistor is active if the voltage at Pin MON-I falls below the internal threshold voltage. The comparator can be used to monitor the power-supply battery. Power Supply The power-supply circuit generates the internal supply voltage from an external voltage (VS = 2.4 V to 12 V).The Pin VS is protected by an internal suppressor diode WAKE Busy internal circuit state Standby tSB tSB Standby DATA IRED td Output current MON-I MON-O 95 9878 Figure 4. Timing diagram Rev. A2, 15-Oct-98 3 (6) U426B Absolute Maximum Ratings Parameters Supply voltage Supply current t < 10 ms Input voltages Input currents Output voltage Output current t < 100 ms Pin 1 Symbol VS IS is VI II V7 V4 I7 I4 Ptot Ptot Ptot Tj Tamb Tstg Value 13.4 40 150 VS 1 1 13.4 VS 1.5 5 150 250 430 125 -40 to 85 -40 to 150 Unit V mA mA V V mA V V A mA mW mW mW C C C Pins 2, 3 and 5 Pin 6 Pins 2, 3 and 5 Pin 7 Pin 4 Pin 7 Pin 4 Power dissipation Tamb = 85C SO8 : on PC board on ceramic on ceramic with silicon grease Junction temperature Ambient temperature range Storage temperature range Thermal Resistance Junction ambient Parameters SO8: on PC board on ceramic on ceramic with silicon grease Symbol RthJA RthJA RthJA Value 220 140 80 Unit K/W K/W K/W Electrical Characteristics VS = 6 V, Tamb = 25C, reference point Pin 8, unless otherwise specified Parameters Supply current Supply voltage Standby current Wake-up current Overvoltage protection DATA Input signal Common-mode input Rise time Fall time Signal frequency Input current MON-I Reverse current Input voltage HIGH Input voltage LOW Hysteresis Temperature coefficient Input current 4 (6) Test Conditions / Pins Pin 1 Pin 1 Without pulse I1 = 20 mA Pin 2 High Low V2 V2 tr tf f I2 Pin 3 V3 = 0 V MON-I on MON-O off Ir V3 V3 TC I3 485 515 525 545 4 100 0.8 555 580 3 1.6 0 3.6 2.1 4.2 2.6 VS 500 500 500 100 V V V ns ns kHz Symbol VS II II VS Min. 2.4 Typ. Max. 12 2 1.5 13 Unit V mA mA V mA mA mV mV % V3 = 6 V 0.3 mA/K mA Rev. A2, 15-Oct-98 U426B Electrical Characteristics (continued) VS = 6 V, Tamb = 25C, reference point Pin 8, unless otherwise specified Parameters MON-O Output current Output current Reverse current Output voltage HIGH Saturation voltage WAKE Input current Input voltage HIGH Input voltage LOW SHUNT Output current IRED Test Conditions / Pins Pin 4 V4 200 mV V4 400 mV V4 6 V I4 = 1 mA Pin 5 V5 = 6 V V5 = 0 V Busy Standby Pin 6 VS = 2.4 V; RS = 0.62 W VS = 6.0 V; RS = 0.62 W VS = 12 V; RS = 0.62 W VS = 6 V; RS = 0.11 W VS = 12 V; RS = 0.11 W V2 = VS = 6 V; RS = 0.11 W Tamb = -40 to 85C Pin 7 V2 = VS = 6 V; I7 = 1 A V2 =0 V; I7 = 0 V2 =0 V; V7 = 6 V Pin 2 to Pin 7 I5 I5 V5 V5 I7 I7 I7 I7 I7 VShunt TC Vout Vout Ir tr td tSB tBS 5.2 4.8 3.7 1.4 0.4 1.27 3.81 8 5 0.25 0.10 0.2 3.8 6.15 5.85 Symbol I4 I4 Ir Vsat Min. 1 3 Typ. Max. Unit mA mA 0.2 VS 200 80 0.2 VS 0.2 245 265 275 1.5 1.55 160 mA V mV mA mA V V mA mA mA A A mV 0 205 220 235 1.25 1.3 140 Shunt voltage Temperature coefficient IRED Output voltage Output voltage Reverse current Rise/fall time Delay time Standby/busy Busy/standby 150 40 mV/K 1000 13.2 1 300 1 1 1 mV V 12 mA ms ms ms ns Package Information Package SO8 Dimensions in mm 5.00 4.85 technical drawings according to DIN specifications 13034 1 4 Rev. A2, 15-Oct-98 5 (6) U426B Ozone Depleting Substances Policy Statement It is the policy of TEMIC Semiconductor GmbH to 1. Meet all present and future national and international statutory requirements. 2. Regularly and continuously improve the performance of our products, processes, distribution and operating systems with respect to their impact on the health and safety of our employees and the public, as well as their impact on the environment. It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as ozone depleting substances ( ODSs). The Montreal Protocol ( 1987) and its London Amendments ( 1990) intend to severely restrict the use of ODSs and forbid their use within the next ten years. Various national and international initiatives are pressing for an earlier ban on these substances. TEMIC Semiconductor GmbH has been able to use its policy of continuous improvements to eliminate the use of ODSs listed in the following documents. 1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively 2 . Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental Protection Agency ( EPA) in the USA 3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C ( transitional substances ) respectively. TEMIC Semiconductor GmbH can certify that our semiconductors are not manufactured with ozone depleting substances and do not contain such substances. We reserve the right to make changes to improve technical design and may do so without further notice. Parameters can vary in different applications. All operating parameters must be validated for each customer application by the customer. Should the buyer use TEMIC products for any unintended or unauthorized application, the buyer shall indemnify TEMIC against all claims, costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal damage, injury or death associated with such unintended or unauthorized use. TEMIC Semiconductor GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany Telephone: 49 ( 0 ) 7131 67 2594, Fax number: 49 ( 0 ) 7131 67 2423 6 (6) Rev. A2, 15-Oct-98 |
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