5 4 3 2 1 REVISION HISTORY ECO REV __ 3.3V J6 * C1 1uF 0603 J7 C2_F1 + C2 J8 C9 1uF 0603 J9 330uF 10V 7343 R18 0 7 C27 0.1uF 3.3V 8 MUTE LDO 3.3V C17 0.1uF 3.3V 3.3V 23 GNDD V+VCO 25 24 26 CP V+CP L1 68nH 0402HPH-68NXJL C20 100pF RF- 1. ALL RESISTORS ARE IN OHMS, 0402 2. ALL CAPACITORS ARE IN MICROFARADS, 0402 A B C D LTC6948-1 LTC6948-2 LTC6948-3 LTC6948-4 5 3.3V C18 1uF 0603 SUFFIX VCO C2_F1 CI1 CP R1_F1, RZ 1 2 3 4 2.24 TO 3.74 GHz 3.08 TO 4.91 GHz 3.84 TO 5.79 GHz 4.20 TO 6.39 GHz 2.4nF 2nF 1.8nF 1.6nF 82nF 68nF 56nF 56nF 3.6nF 3nF 2.4nF 2.4nF 57.6 63.4 75 76.8 C22 0.1uF C21 100pF RF+ CUSTOMER NOTICE 4 TUNE J5 SMA-R NOTE: UNLESS OTHERWISE SPECIFIED * 15 L2 3.3V 68nH 0402HPH-68NXJL J4 SMA-R U1 0603 C19 0.01uF JP1 ASSY 17 C16 2.2uF B 1 GND C2_F2 OPT 0603 16 TUNE R19 0 2 B 18 TB QFN28UFD-4X5 V+D R20 0 3 V+REF 28 GNDB 9 2 C28 OPT 0603 CMC SDO MUTE D1 LN1251C 19 CMB SDI C BB 6 20 CMA SCLK C15 1uF 0603 21 GNDC V+RF SDO 22 14 1 SDI 5 CS C13 0.01uF BVCO 13 4 * RF+ CS SCLK U1 STAT 12 3 RF- 2 STATUS REF+ GNDA E3 11 1 10 C 27 29 GND R1 51.1 R3 330 0805 R1_F2 OPT 0603 REF- SMA-R L1_F2 OPT 0805 C11 1uF C6 1uF J1 REF+ IN D C8 1uF 0603 C12 0.01uF A * 5V R4 15 C7 0.1uF 09-21-15 *0603 CI1 0603 CI2 OPT R2 0 + C10 GND * 0603 3.3V 5V DATE CHRIS P. RZ CP 0603 5V APPROVED REBUILD WITH CHANGE 0805 0603 * 330uF 10V 7343 GND D L1_F1 10uH R1_F1 3.3V DESCRIPTION 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 APPLICATION. COMPONENT SUBSTITUTION AND PRINTED APP ENG. CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. TECHNOLOGY KIM T. CHRIS P. TITLE: SCHEMATIC ULTRALOW NOISE & SPURIOUS FRACTIONAL-N SYNTHESIZER WITH INTEGRATED VCO SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 3 N/A SCALE = NONE 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: IC NO. LTC6948IUFD-1/2/3/4 REV. 1 DEMO CIRCUIT 1959B Monday, September 21, 2015 SHEET 1 1 OF 2 A 5 4 3 2 1 DC590 SPI INTERFACE 3.3V D U2 NC7WZ17P6X R5 200K 1 6 3 4 R10 100 R11 100 SCLK 3.3V GND VCC 5 C23 0.1uF 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 U3 NC7WZ17P6X R9 4.99K C26 0.1uF WP R21 100 R15 0 0603 B EEGND 6 3 4 2 GND VCC R12 100 3.3V C24 0.1uF 3.3V C25 0.1uF 5 U4 74LVC1T45GW 4 SCL SDA WP A2 A1 A0 ARRAY 13 8 3 6 5 7 3 2 1 1 SDI C 8 U5 24LC025-I /ST C3 0.1uF R7 200K VCC R8 4.99K R6 200K GND R14 4.99K GND GND GND C 2 EEPROM J2 HD2X7-079-MOLEX D CS 1 VCC(A) 2 GND 3 VCC(B) 6 DIR 5 4 SDO B R13 200K NOTE: EEPROM FOR BOARD IDENTIFICATION 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 APPLICATION. COMPONENT SUBSTITUTION AND PRINTED APP ENG. CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. A TECHNOLOGY KIM T. CHRIS P. TITLE: SCHEMATIC 5 4 3 IC NO. DATE: REV. LTC6948IUFD-1/2/3/4 N/A SCALE = NONE A ULTRALOW NOISE & SPURIOUS FRACTIONAL-N SYNTHESIZER WITH INTEGRATED VCO SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only 1 DEMO CIRCUIT 1959B Monday, September 21, 2015 SHEET 2 1 2 OF 2