4266G 4267G 4268G 4269G 4262G 4263G 4264G SO-20 B192H6641-X4-X-7400 - Datasheet Archive

 

ICs for Automotive Electronics Frank Schwertlein Common features of the TLE 426X family of low-drop voltage regulators Low-drop

 

APPLICATIONS ICs for Automotive Electronics Frank Schwertlein Common features of the TLE 426X family of low-drop voltage regulators Low-drop voltage regulators save battery power The growing use of electronic systems in automotive engineering has increased the need for low-drop voltage regulators with a low quiescent current to minimize drain on the battery. A comprehensive and considerably enlarged family of ICs from the Semiconductor Group meets this and many other typical requirements of modern motor vehicles. asically, there are two ways of saving battery current in automotive electronic systems. In systems which need no current when the vehicle is parked, the B q Low drop voltage of only 0.35 V q Outputs protected against short circuits q Output voltage 5 V q Protection against excess temperature q Protection against polarity reversal of supply voltage q voltage regulators can be switched off with the aid of an inhibit signal. But systems which must remain active when the vehicle is parked, such as electronic immobilizers or alarms, require voltage regulators with a very low quiescent current and immunity to interference at the same time. The Semiconductor Group offers several innovative ICs for both types of application. Low quiescent current consumption q Designed and tested for EMC The TLE 426X family of low-drop voltage regulators in TO or SO packages (Table 1) has now grown to ten different ICs, all designed for an output voltage of 5 V. New to the family are types TLE 4266G 4266G, TLE 4267G 4267G, TLE 4268G 4268G and TLE 4269G 4269G. These SMDs are highlighted in Table 1, while Table 2 lists their special features. Low drop Voltage regulators with turn-off via inhibit A low drop voltage is an important parameter in the design of voltage regulators for automotive applications. The drop voltage of all the voltage regulators presented here is only 0.35 V at the rated current. This very low potential difference is the minimum needed between the input and output of the voltage regulators to maintain a smooth output voltage and thus ensure a reliable supply of power to the electronic devices connected. When the voltage regulators are turned off via the inhibit input, current consumption drops to a few microamperes (leakage current 50 A). The supply voltage is then fed to the application circuit straight from the battery voltage via "terminal 30" and is switched on or off via the ignition lock in a wattless state. Typical applications for this kind of voltage regulator are engine management modules, ABS and airbags, for which types TLE 4261, TLE 4262G 4262G, TLE 4263G 4263G, Table 1 Overview of 5 V low-drop voltage regulators for automotive applications Parameters TLE 4260 TLE 4261 TLE 4262G 4262G TLE 4263G 4263G TLE 4264G 4264G TLE 4265 TLE 4266G 4266G TLE 4267G 4267G TLE 4268G 4268G TLE 4269G 4269G Max. supply voltage Load dump protection Drop voltage Output current Accuracy of output voltage Leakage current Quiescent current 1 mA Short circuit protection Overvoltage protection Overtemperature protection Adjustable reset time Adjustable reset threshold Inhibit input Watchdog circuit Reverse polarity protection Package 45 65 0.35 500 5%/2% 14 45 45 45 45 45 0.35 200 2% 50 720 0.35 200 2% 50 850 0.35 200 2% 0.35 200 2% 600 45 65 0.35 500 5%/2% 50 2600 450 720 0.35 200 2% 0 450 26 60 0.35 400 2% 0 1300 45 45 0.35 200 2% 0.35 150 2% 350 150 A A V V V mA TO-220 TO-220/ SO-20 SO-20 SO-20 SO-20 SO-20 SO-20 SOT-223 TO-220 SOT-223 TO-220/ SMD SO-20 SO-20 SO-8 DIP-8, SO-20 SO-20 Components XXX (1995) No. 5 APPLICATIONS ICs for Automotive Electronics TLE 4266G 4266G and TLE 4267G 4267G can be used. All these voltage regulators have an inhibit input, but different output currents and supplementary functions, e.g. a watchdog. The TLE 4261 has an inhibit function that can be activated only by a voltage greater than 5 V. In the turned-on state, a hysteresis effect ensures that the system can be kept active by a logic circuit or microcontroller. This guarantees that the circuit can be switched on only via the ignition lock. Once the ignition key has been removed and the vehicle locked, a data security function can be activated because the controller itself determines when the voltage regulator is to be deactivated. In contrast, voltage regulators TLE 4262G 4262G, TLE 4263G 4263G and TLE 4266G 4266G can be switched on by a TTL signal. Here too, a wired OR status can be triggered by logic signals via the ignition lock. Only two external diodes are needed for this purpose. This wired-OR feature has already been integrated into the TLE 4267G 4267G, so that external diodes are dispensed with and costs saved. The follow-up signal is simply fed to a second pin. Voltage regulators for systems remaining active in parked vehicles ICs TLE 4264G 4264G, TLE 4266G 4266G, TLE 4268G 4268G and TLE 4269G 4269G are ideal for such active systems. Despite the very low quiescent currents, an unprecedented degree of immunity to interference has been achieved. These voltage regulators are, of course, eminently suitable for many other applications. Thanks to their precise output voltage with a fine tolerance of only ±2% and compact, low-cost SOT-223 packages, the TLE 4264G 4264G and TLE 4266G 4266G low-drop voltage regulators are highly suitable as decentralized tracking regulators. Dividing functions between main and standby regulators and the associated splitting up of power dissipation between two packages reduce thermal radiation, which benefits SMDs with their small surface areas in particular. The TLE 4268G 4268G features a watchdog function as well as a delayed reset. The watchdog can monitor a microcontroller. It can switch itself off as a function of load so that the low current consumption of only 250 µA is not increased by "waking up" the controller unnecessarily from its sleep mode. Adjustable reset threshold and early warning function for new microcontroller generations The growing number of automotive systems which remain active has increased the demand for voltage regulators with a low quiescent current consumption. At the same time, there is a distinct decline in systems fed straight from the ignition lock via "terminal 15". Typical applications are central door locking systems, immobilizers and car radios. The new voltage regulator To match new generations of microcontrollers which operate perfectly even at supply voltages below 4.5 V, the TLE 4268G 4268G has an adjustable reset switching threshold. This function has likewise been integrated into the TLE 4269G 4269G. This voltage regulator has an early warning function, instead of a watchdog, which can monitor any Fig. 1 Search tree for 5-V low-drop voltage regulators (Y = Yes, N = No) TLE 4266G 4266G q Inhibit function q SOT-223 package TLE 4267G 4267G q On/off logic (2 pins) q High load current of 400 mA q Inhibit function q Excess voltage protection q TO-220 package TLE 4268G 4268G q Load-dependent watchdog function q Adjustable reset threshold q Low quiescent current of 250 A q SO-20 SO-20 package TLE 4269G 4269G q Early warning function q Very low quiescent current of 150 A q Adjustable reset threshold q Very compact SO-8 package Table 2 Distinguishing criteria and special features of the new 5 V low-drop voltage regulators in SMD packages voltage. In the standard application, it monitors its own supply voltage. Data can thus be saved in good time if the supply voltage fails. Search tree The search tree shown in Fig. 1 makes it easier for electronics designers to select the right voltage regulator for their applications. Further details can obtained from the CD-ROM Technical Product Information for Siemens Semiconductors (Order No. B192H6641-X4-X-7400 B192H6641-X4-X-7400), which can be obtained through local Siemens companies. Data sheets are also available for the various low drop voltage regulators on request. Check #5-95-1 (HL) on Reader Service Card TLE 4261 Watchdog Y N Inhibit Y N TLE 4260 Inhibit Y N Reset Y N Reset Y N Output current Y > 150 mA N TLE 4267 Watch- Y dog N TLE 4266 Watch- N dog Y TLE 4264 Components XXX (1995) No. 5 TLE 4263 TLE 4262 Early Y warning N TLE 4268 TLE 4269 TLE 4265 Frank Schwertlein, Dipl.-Ing. (FH) joined Siemens in 1986 as a designer of power ICs. Since August 1994 he has been responsible for voltage regulators in product marketing in the Semiconductor Group. 15