DEMO MANUAL DC249 LOW NOISE CONVERTER LTC1682 Doubler Charge Pump with Low Noise Linear Regulator DESCRIPTIO Demonstration Circuit DC249 is a doubler charge pump powered systems that require extremely low output volt- and linear regulator that produces a regulated, low noise age noise and small size. output voltage from an input voltage ranging from 1.8V to A DC249 demo board is available for the LTC1682CMS8, 4.4V. Two fixed output voltages of 3.3V and 5V are LTC1682CMS8-3.3 and the LTC1682CMS8-5. The available. In addition, an adjustable output voltage version LTC1682CMS8 demo board does not include the feedback is available with an output voltage range of 2.5V to 5.5V. resistors used to set the output voltage. The user must The LTC 1682 family can supply up to 50mA of output calculate the resistor values based on the required output current. The circuit requires only small surface mount voltage and add them to the board. Gerber files for this components, resulting in very small board area. The circuit board are available. Call the LTC factory. power supply circuit is particularly useful in battery- , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. PERFORmANCE SU ARY PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage 1.8 4.4 V IN I Shutdown Current SHDN = 0V 1 5 m A VIN TM I Quiescent Current I = 0mA, Burst Mode Operation, SHDN > 1.6V 150 250 m A VIN OUT V RMS Output Noise LTC1682-3.3: I = 10mA, 10Hz f 100kHz, C = 1nF 58 m V OUT OUT FILT RMS LTC1682-5: I = 10mA, 10Hz f 100kHz, C = 1nF 64 m V OUT FILT RMS V Wideband Output Noise I = 10mA, SHDN > 1.6V, BW = 10Hz f 2.5MHz OUT OUT LTC1682-3.3, V = 3V 500 m V IN P-P LTC1682-5, V = 3V 600 m V IN P-P LTC1682 Adjustable, V = 5V, V = 3V 800 m V OUT IN P-P V (LTC1682-3.3) SHDN > 1.6V 3.23 3.30 3.37 V OUT V (LTC1682-5) SHDN > 1.6V 4.9 5.0 5.1 V OUT V (LTC1682) SHDN > 1.6V, Internal Reference Tolerance 2 2 % OUT TYPICAL PERFORMANCE CHARACTERISTICS AND BOARD PHOTO Board Photo Typical Output Noise V OUT 200m V/DIV AC COUPLED 100m s/DIV DC249-BD BW = 10Hz to 2.5MHz I = 10mA, V = 3V DC249-02 OUT IN 1 U U W WW UW UDEMO MANUAL DC249 LOW NOISE CONVERTER PACKAGE A D SCHE ATIC DIAGRA SM LTC1682 Schematic Diagram E2 LTC1682 SHUTDOWN E1 8 1 V CPO V OUT OUT 2.5V TO 5.5V 7 2 C3 + R1 C SHDN 4.7F 6 3 C4 E4 CONNECT LOAD V FB IN 4.7F V ACROSS E1 AND E5 IN C1 0.22F 5 C2 4 R2 C GND 4.7F E5 E3 GND DC249-03 GND NOTE: USER MUST SUPPLY R1 AND R2 TOP VIEW TO SET OUTPUT VOLTAGE AS FOLLOWS: V 1 8 CPO OUT V = 1.235V 1 + (R1/R2) OUT + SHDN 2 7 C FILT/FB 3 6 V IN GND 4 5 C LTC1682-3.3/LTC1682-5 Schematic Diagram MS8 PACKAGE 8-LEAD PLASTIC MSOP LTC1682-3.3 LTC1682-5 E1 LTC1682CMS8 8 1 V V CPO OUT OUT LTC1682CMS8-3.3 3.3V or 5V LTC1682CMS8-5 7 2 C3 E2 + SHDN C 4.7F SHUTDOWN C4 6 3 CONNECT LOAD E4 FILT V IN 4.7F ACROSS E1 AND E5 V IN C1 0.22F 5 C C2 4 FILT GND C 1nF 4.7F E5 E3 DC249-04 GND GND PARTS LIST REFERENCE DESIGNATOR QUANTITY PART NUMBER DESCRIPTION VENDOR TELEPHONE C1 1 0805YC224KAT2A 0.22m F 16V 10% X7R Capacitor AVX (843) 946-0362 C2, C4 2 0805ZG475ZAT2A 4.7m F 10V Y5V Capacitor AVX (843) 946-0362 C3 1 1206YG475ZAT2A 4.7m F 16V Y5V Capacitor AVX (843) 946-0362 E1 to E5 5 2501-2 0.090 Turret Testpoint Mill-Max (516) 922-6000 R1, R2 2 TBD TBD Resistor TBD U1 1 LTC1682MS8 8-Lead MSOP IC Version A LTC (408) 432-1900 LTC1682MS8-5 8-Lead MSOP IC Version B LTC1682MS8-3.3 8-Lead MSOP IC Version C NOTE: For LTC1682-3.3 and LTC1682-5: Replace R2 with a 1nF 16V 10% X7R ceramic capacitor (AVX 0603YC102KAT2A) and omit R1. 2 W WU