2 3 4 5 6 J3 J10 GNDD SCLK GNDC SDI GNDB SDO VCO+ GND D -A U3 CVCO55CL-0902-0928 VCO U1 18 LTC6945IUFD 17 16 12 15 BB V+RF 19 1. ALL RESISTORS ARE IN OHMS, 0402 ALL CAPACITORS ARE IN MICROFARADS, 0402. 11 C26 100pF 10 9 C28 OPT + GND GND GND VTUNE RFOUT GND GND GND C35 0805 2 3 U4 OPT VTUNE EN GND VCC NC RFOUT 6 5 47uF 35V E15 0.1uF E16 GND B GND 4 1 R24 OPT 2 E17 3 4 E18 C27 OPT 0603 V+VCXO R23 OPT GND EN C C32 OPT 0603 J5 L1 OPT THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 3 C33 7361 1 APPROVALS LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 902 - 928 MHz 2 R17 OPT 0603 * CUSTOMER NOTICE RF+ NOTE: UNLESS OTHERWISE SPECIFIED 1 C42 100pF V+VCO EXT VCO IN J6 RF- E13 3.3V C45 0.01uF C38 100pF R10 0 0603 C25 OPT 0.01uF L3 68nH J7 ASSY 20 C31 1.0uF 14 RF+ L2 68nH C37 100pF * 13 12 RF- GNDA 11 MUTE 9 3.3V JP1 0603 0 OPT V+VCXO C19 V+VCO 47uF 35V 7361 C21 0.1uF U3 0805 21 GND V+VCO E14 8 MUTE R14 1206 3.3V C23 0.01uF 22 C29 100pF 3.3V C34 3.3V OPT 16 GNDE CS 3.3V OPT R13 GND GNDF STAT V+D J11 0603 14 V+VCO REFO 10 C30 0.1uF A 5V CPGAIN 0603 CI2_P 0.1uF VCO8 CI1_P V+OA 5V J4 RZ_P 806 0603 15 24 V+CP 25 V+REFO 3.3V C E11 J12 GND 7 47uF 35V C2 0.1uF 0805 5 6 C16 330uF CP_P 10V 8200pF 7343 0603 VCC 5 SCLK SDI SDO + OPT 1206 GND 4 CS C18 1.0uF 0805 13 3 09-30-11 0603 GND 2 DATE MICHEL A. + 1 CP REF- 28 E6 APPROVED OPT CI2_A 470pF 27 C15 DESCRIPTION PRODUCTION CPGAIN CI1_A GND 2 B STATUS C17 0.1uF 26 1 C8 470pF C24 0.1uF REF+ R4 330 D1 LN1251C 4 E12 0603 5V V+REF J1 3.3V RZ_A OPT 29 REF0 R5 51.1 GND C11 0.1uF 23 J2 8 REV CP_A OPT 0603 R16 0 0603 REF+ V- GND C4 0.1uF GND GND C5 1.0uF 4 C7 47uF 7343 20V R15 OPT 0603 C1 7361 V+ 7 OUTB 6 -INB B 5 +INB 6 + C3 330uF 10V 7343 OUTA -INA A 3 +INA 2 + J9 U2 LT1678IS8 1 C6 0.1uF 0805 3.3V 3.3V C12 1.0uF 7 CP OPT ECO __ V+OA R1 4.99K R2 4.99K GNDG A E3 8 REVISION HISTORY 5V CP 7 + 1 4 5 TECHNOLOGY KIM T. MICHEL A. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: SCHEMATIC ULTRALOW NOISE AND SPURIOUS INTEGER-N SYNTHESIZER SIZE N/A SCALE = NONE 6 DATE: LTC6945IUFD IC NO. REV. 4 DEMO CIRCUIT 1649A 09/30/2011, 11:05 AM 7 SHEET 1 8 OF 2 D A B C D 3.3V 4 1 3 R26 4.99K 5 C41 4 SCLK 0.1uF R8 200K 3 4 2 VCC C36 0.1uF GND 1 VCC(A) 2 GND 3 VCC 3.3V 5 SDI C44 0.1uF 3 3.3V VCC(B) 6 DIR 5 C39 0.1uF 4 SDO 2 R18 200K CUSTOMER NOTICE APPROVALS LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. B 6 U7 74LVC1T45GW R9 0 0603 EEGND 1 R12 100 8 C43 0.1uF 4 13 8 3 SCL SDA WP A2 A1 A0 R7 200K GND U8 24LC025-I /ST ARRAY R25 4.99K EEPROM R27 4.99K WP A VCC 3.3V U6 NC7WZ17P6X 6 5 7 3 2 1 1 R22 100 4 GND CS V+DIG CS SCLK SDI SDO 1 V+ 2 5V 6 CS 4 SCK/SCL 7 MOSI/SDA 5 MISO 10 EEVCC 9 EESDA 11 EESCL 12 EEGND 14 AUX 2 R21 100 6 2 GND GND GND 3 U5 NC7WZ17P6X R19 200K DC590B SPI INTERFACE J8 HD2X7-079-MOLEX E C TECHNOLOGY KIM T. MICHEL A. TITLE: SCHEMATIC 1 ULTRALOW NOISE AND SPURIOUS INTEGER-N SYNTHESIZER SIZE LTC6945IUFD IC NO. N/A SCALE = NONE 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: REV. 4 DEMO CIRCUIT 1649A 09/30/2011, 11:05 AM D SHEET 2 E OF 2