Texas Instruments new TPS201x family of protected high-side switches use a new approach, combining "smart" protection with low-loss high-side switches. Their maximum 95-m½ rDS(on) competes with some of the best PMOS switches available today. Operation down to 2.7 V and a logic-compatible ENABLE make them suitable for 3-V and 5-V systems. The TPS201xD in 8-pin SOIC drops into the same footprint as Siliconix LittleFoot™ switches.* Applications requiring lower profile can take advantage of the TPS201xPWLE in TSSOP, with a maximum height of just 1.15 mm.
In addition to efficient power switching, the TPS201x features built-in current limiting to prevent damage in the event of a short circuit. An internal "sense FET" monitors current through the switch, triggering current limiting circuitry when a preset threshold is exceeded. Using a FET instead of series resistance to sense current improves efficiency, allowing higher currents to be switched in small surface-mount packages. The four devices in the TPS201x family feature a range of overcurrent thresholds suitable for a variety of applications from barcode scanners to laptop computers, from 400 mA to 2.6 A (see table).
System reliability is improved by disabling the switch if its junction temperature rises to an unsafe level. Other unprotected switches, even with current limiting, could overheat and burn up in the event of a sustained short circuit. By disabling the switch, the TPS201x prevents thermal runaway. When the junction temperature returns to a safe level, the load is automatically reconnected.
The TPS201x is protected against up to 12 kV discharge at the outputs, 6 kV on all other pins. To reduce electromagnetic radiation generated by high-current switching transients, the TPS201x controls switching rise and fall times. This reduces interference with sensitive electronics.
The TPS201x high performance high-side switches go a step beyond the competition. For the price of a simple switch, they also protect against short circuits, thermal runaway, and ESD, and reduce the effects of switching transients. Small 8-pin SOIC and ultra-low-profile TSSOP options fit tight spaces.
Device Recommended Maximum Typical Short-Circuit Continuous Load Current Output Current Limit at 25°C TPS2010 200 mA 400 mA TPS2011 600 mA 1.2 A TPS2012 1 A 2 A TPS2013 1.5 A 2.6 A
Vol 12, Summer, 1995