LT1175 500mA Negative Low Dropout Micropower Regulator FEATURES DESCRIPTION n Operating Current: 45A The LT 1175 is a negative micropower low dropout n Adjustable Current Limit regulator. It features 45A quiescent current, dropping n Low Voltage Linear Dropout Characteristics to 10A in shutdown. A new reference ampli er topology n Stable with Wide Range of Output Capacitors gives precision DC characteristics along with the ability to n Shutdown Current: 10A maintain good loop stability with an extremely wide range n Positive or Negative Shutdown Logic of output capacitors. Very low dropout voltage and high n Fixed 5V and Adjustable Versions ef ciency are obtained with a unique power transistor n Tolerates Reverse Output Voltage anti-saturation design. Adjustable and xed 5V versions n Available in 8-pin PDIP and SO Packages, 3-lead are available. SOT-223, 5-Pin Surface Mount DD and Through-Hole Several new features make the LT1175 very user-friendly. TO-220 Packages The SHDN pin can interface directly to either positive or negative logic levels. Current limit is user-selectable at APPLICATIONS 200mA, 400mA, 600mA and 800mA. The output can be forced to reverse voltage without damage or latchup. Un- n Analog Systems like some earlier designs, the increase in quiescent current n Modems during a dropout condition is actively limited. n Instrumentation n A/D and D/A Converters The LT1175 has complete blowout protection with current n Interface Drivers limiting, power limiting and thermal shutdown. Special n Battery-Powered Systems attention was given to the problem of high temperature L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear operation with micropower operating currents, preventing Technology Corporation. All other trademarks are the property of their respective owners. output voltage rise under no-load conditions. The LT1175 is available in 8-pin PDIP and SO packages, 3-lead SOT- 223 as well as 5-pin surface mount DD and through-hole TO-220 packages. The 8-pin SO package is specially constructed for low thermal resistance. TYPICAL APPLICATION Minimum Input-to-Output Voltage 1.0 T = 25C Typical LT1175 Connection J I , I TIED TO V LIM2 LIM4 IN 0.8 + + C OUT C * IN 0.1F 0.6 SHDN GND 5V V SENSE V IN IN UP TO 500mA 0.4 I LT1175-5 LIM2 I OUTPUT LIM4 0.2 *C IS NEEDED ONLY IF REGULATOR IS MORE THAN 6 FROM IN 0 INPUT SUPPLY CAPACITOR. SEE APPLICATIONS INFORMATION 0 0.2 0.3 0.4 0.5 0.7 1175 TA01 0.1 0.6 SECTION FOR DETAILS OUTPUT CURRENT (A) 1175 TA02 1175ff 1 INPUT-TO-OUTPUT VOLTAGE (V)LT1175 (Note 1) ABSOLUTE MAXIMUM RATINGS Input Voltage (Transient 1 sec, Note 12) ...................25V Output Reverse Voltage ..............................................2V Input Voltage (Continuous) .......................................20V SHDN Pin to GND Pin Voltage (Note 3) ........13.5V, 20V Input-to-Output Differential Voltage (Note 13) ..........20V SHDN Pin to V Pin Voltage .............................30V, 5V IN 5V SENSE Pin (with Respect to GND Pin) ......... 2V, 10V Operating Junction Temperature Range (Note 2) ADJ SENSE Pin LT1175C ................................................. 0C to 125C (with Respect to OUTPUT Pin) ...................20V, 0.5V LT1175I .............................................. 40C to 125C 5V SENSE Pin LT1175MP .......................................... 55C to 125C (with Respect to OUTPUT Pin) ......................20V, 7V Storage Temperature Range .................. 65C to 150C Lead Temperature (Soldering, 10 sec)...................300C PIN CONFIGURATION FRONT VIEW TOP VIEW FRONT VIEW 3 GND V V 1 8 5 SHDN IN IN 4 GND TAB TAB IS I 2 7 I LIM2 LIM4 2 V 3 V IS V IN IN IN 2 V SENSE OUTPUT 3 6 SHDN IN 1 OUTPUT 1 OUTPUT SENSE 4 GND 5 Q PACKAGE ST PACKAGE 5-LEAD PLASTIC DD-PAK N8 PACKAGE 3-LEAD PLASTIC SOT-223 8-LEAD PDIP = 27C/W TO 60C/W JA = 50C/W JA = 80C/W TO 120C/W DEPENDING ON PC MOUNTING. JA 2 WITH BACKPLANE AND 10cm DEPENDING ON PC BOARD LAYOUT SEE DATA SHEET FOR DETAILS TOPSIDE LAND SOLDERED TO TAB TOP VIEW V 1 8 V IN IN FRONT VIEW I 2 7 I LIM2 LIM4 5 SHDN OUTPUT 3 6 SHDN 4 GND SENSE GND 4 5 3 V IN 2 SENSE S8 PACKAGE 1 OUTPUT 8-LEAD PLASTIC SO TAB IS = 60C/W TO 100C/W JA V DEPENDING ON PC BOARD LAYOUT IN T PACKAGE 5-LEAD PLASTIC TO-220 PINS 1, 8 ARE INTERNALLY CONNECTED TO DIE ATTACH PADDLE FOR HEAT SINKING. = 50C/W, = 5C/W JA JC ELECTRICAL CONTACT CAN BE MADE TO EITHER PIN. FOR BEST THERMAL RESISTANCE, PINS 1, 8 SHOULD BE CONNECTED TO AN EXPANDED LAND THAT IS OVER AN INTERNAL OR BACKSIDE PLANE. SEE APPLICATIONS INFORMATION 1175ff 2