DEMO MANUAL DC092 GaAsFET BIAS GENERATOR LTC1550/LTC1551 Low Noise, Switched Capacitor, Regulated Voltage Inverter DESCRIPTIO Demonstration circuit DC092 is a low noise, regulated polarity of the Shutdown pin. DC092-A uses the LTC1550- voltage inverter using the LTC 1550/LTC1551. The all 4.1CS8, which has an active low Shutdown pin (SHDN), surface mount design demonstrates the small size and while DC092-B uses the LTC1551-4.1CS8 with an active compact layout possible with the LTC1550/LTC1551. It is high Shutdown pin (SHDN). The LTC1550/LTC1551 oper- designed for applications such as bias voltage generators ate with a supply voltage of 4.5V to 6.5V and produce a for GaAs transmitter FETs in portable RF equipment and fixed 4.1V 5% output. Normal operating quiescent cellular telephones. This demo board highlights the low current is 4mA at no load condition. noise capabilities of the LTC1550/LTC1551, which uses Other members of the LTC1550/LTC1551 family contain an internal linear post regulator to limit output ripple to additional features such as adjustable output voltage, 1mV . P-P lower minimum V voltage requirements and an open- CC The LTC1550/LTC1551 provide a TTL compatible Shut- drain output that indicates when the output voltage is in down pin that reduces the supply current typically to regulation. Please refer to the LTC1550/LTC1551 data 0.2A. The LTC1550/LTC1551 are identical except for the sheet for more information. , LTC and LT are registered trademarks of Linear Technology Corporation. PERFOR A CE SU ARY (30C < T < 85C) A SYMBOL PARAMETER CONDITIONS BOARD SUFFIX VALUE V Supply Voltage All 4.5V to 6.5V CC I Supply Current I = 0mA All 4mA Typ S OUT I = 5mA All 9mA Typ OUT I = 10mA All 14mA Typ OUT Shutdown All 0.2A Typ SHDN Shutdown LTC1550-4.1 A TTL Low Level LTC1551-4.1 B TTL High Level TYPICALPERFOR A CECCHARA TERISTICSAD BOARD PHOOT S V Output Noise and Ripple Component Side OUT 2mV/DIV DC092 TA01 10s/DIV V = 5V IN V = 4.1V OUT I = 5mA OUT AC COUPLED 1 U UW U W WW UDEMO MANUAL DC092 GaAsFET BIAS GENERATOR PERFOR A CE SU ARY SYMBOL PARAMETER CONDITIONS BOARD SUFFIX VALUE f Internal Oscillator Frequency All 900kHz Typ OSC V Ripple Voltage All 1mV Typ RIPPLE P-P V Output Voltage V = 4.5V, 0 < I < 5mA All 3.9V to 4.3V OUT CC OUT V = 5V, 0 < I < 10mA All 3.9V to 4.3V CC OUT V = 6V, 0 < I < 20mA All 3.9V to 4.3V CC OUT V = 6.5V, 0 < I < 25mA All 3.9V to 4.3V CC OUT PACKAGE A D SCHE ATICDIAGRA S U1 LTC1550 LTC1551 TOP VIEW 1 8 SHUTDOWN SHDN SENSE SHDN* 1 8 SENSE 4.5V TO 6V 2 7 E3 V CP CC OUT V V 2 7 CP CC CC OUT C3 1 + C2 JPR1 10F 2 + 0.1F C1 3 6 GND 3 6 10V 3 + E5 C1 GND E4 V 4 5 C1 OUT GND 4 5 E1 V C1 OUT V OUT BEAD S8 PACKAGE J1 8-LEAD PLASTIC SO BNC C1 SHDN FOR LTC1550-4.1 * C OUT C4 0.1F SHDN FOR LTC1551-4.1 10F 0.1F 10V LTC1550-4.1CS8 DC092 F01 E2 LTC1551-4.1CS8 Figure 1.DC092 Schematic (4.1V Generator) PARTS LIST REFERENCE DESIGNATOR QUANTITY PART NUMBER DESCRIPTION VENDOR TELEPHONE C1, C2, C4 3 08055G104ZAT3S 0.1F 50V 20% Y5V Capacitor AVX (803) 946-0362 C3, C 2 595D106X0010A2T 10F 10V 20% Tantalum Capacitor Sprague (207) 324-4140 OUT E1 1 ILB-1206-600 600 25% Bead Dale (605) 665-9301 U1 1 LTC1550-4.1CS8/ Switched Capacitor Voltage Inverter LTC (408) 432-1900 LTC1551-4.1CS8 2 + W W U WW U W