ADRF6655
Rev. 0 | Page 40 of 44
Table 5. Evaluation Board Configuration Options
Component Function Default Condition
VCC, GND, IP3SET, CP,
VCO_LDO, VCC_LO,
VCC_RF, VCC_BB, LE,
CLK, DATA
Power supply, ground, and other test points. Not applicable
R1, R6, R7, R8, R17,
R18, R24, R25, R26,
R29, R31, R32, R36
Power supply decoupling. Shorts or power supply decoupling resistors. R1, R6, R7, R8 = 0 Ω (0402),
R17, R18 = 0 Ω (0402),
R24, R25, R26 = 0 Ω (0402),
R29, R31, R32 = 0 Ω (0402),
R36 = 0 Ω (0402)
C1, C2, C7, C8, C9,
C10, C11, C12, C16,
C17, C18, C19, C20,
C21, C22, C23, C24,
C25, C27, C28, C29,
C39, C41, C42, C43
The capacitors provide the required decoupling of the supply-related pins. C1, C8, C10 = 100 pF (0402),
C2, C39, C41 = 10 μF (0603),
C7, C9, C11 = 0.1 μF (0402),
C12, C16, C18 = 100 pF (0402),
C21, C22, C24 = 100 pF (0402),
C17, C19, C20 = 0.1 μF (0402),
C23, C25, C27 = 0.1 μF (0402),
C28 = 10 μF (3216),
C29 = 0.1 μF (0402),
C42, C43 = 150 pF (0402)
C5, C6, T7, T8 External LO path. T7 and T8 provide different footprints for different LO
path transformer selections. C5 and C6 provide the necessary ac coupling.
C5, C6 = 1 nF (0402),
T7 = open (generic footprint),
T8 = TC1-1-13M+ (Mini-Circuits)
R61, C31, R16 REFIN input path. R61 provides a broadband 50 Ω termination followed
by C31, an ac coupling capacitor. R16 provides an external connectivity
to the MUXOUT feature described in Register 4.
R61 = 49.9 Ω (0402),
C31 = 1 nF (0402), R16 = 0 Ω (0402)
R2, R5, R9, R10, R13,
R37, R38, R62, R63,
R65, R72, C13, C14,
C15, C40
Loop Filter Component Options. A variety of loop filter topologies are
supported using component placements R9, R10, R13, R37, C13, C14,
C15, R65, and C40. R2 provides resistor programmability of the charge
pump current (see Register 4 description). R5, R38, R62, R63, and R72
provide connectivity options to numerous test points for engineering
evaluation purposes.
R2 = R5 = open, R9 = 270 Ω (0402),
R10 = 68 Ω (0402), R13 = 0 Ω (0402)
C13 = 47nF, C14 = 0.1μF,
C15 = 4.7μF (0805),
C40 = open (0402),
R37, R38, R62, R63, R65, R72 = 0 Ω (0402)
L1, L2, R43, R44,
R47, R48, R58, R59,
R73, R74, T3, T6,
C35, C36
IF output path. This is the default configuration of the evaluation board
for downconversion applications. R73 and R74 are populated for
appropriate balun interface. The default values support a TC4-1W+ 4-to-1
impedance ratio transformer with center tap bias connection through
R59. A differential IF output interface can be configured by populating C35
and C36 and omitting R47 and R48. When configuring for differential output
operation or when using an ac-coupled transformer, it is important to use L1
and L2 to provide dc bias to the IF output pins. For additional information,
see the Output Matching and Biasing section.
L1, L2 = open, R44, R58, = open,
R43, R47, R48 = 0 Ω (0402),
R59, R73, R74 = 0 Ω (0402),
T3 = TC4-1W+ (Mini-Circuits),
T6 = open, C35, C36 = open
C37, C38, T4, T5 RF input interface. T4 and T5 provide different footprints for different
RF path transformer selections. C37 and C38 provide the necessary ac
coupling. See the Input Matching section for additional information.
C37, C38 = 100 pF (0402),
T4 = TC1-1-13M+ (Mini-Circuits),
T5 = open
P1, R3, R30, R35,
R50, R51, R52,
R57, C32, C33, C34
Serial port interface. A 9-pin D-sub connector is provided for connecting to a
host PC or control hardware. RC filter networks are provided on CLK, DATA,
and LE lines to help clean up PC control signal wave shape. Test points are
provided for control interface debug. R3 provides a connection to the
MUXOUT for sensing lock detect through the P1 connector. See the Digital
Interfaces section for additional information.
P1 = 9-pin D-sub male,
R3 = 10 kΩ (0402),
R30, R35, R57 = 100 Ω (0402),
R50, R51, R52 = 1 kΩ (0402),
C32, C33, C34 = 330 pF (0402)
C3, R12, R27, R60, L3 IP3SET linearization feature. R27 and R60 provision for a resistive divider
network for providing nominal IP3SET voltage. Alternatively, the IP3SET
pin can be externally driven via the test point or directly connected to
the 3.3 V LDO (Pin 2, DECL1) using a 0 Ω resistor for R12 and a ferrite chip
inductor for L3. For additional information regarding this feature, see the
IP3SET Linearization Feature section.
C3 = 0.1 μF (0402), R12 = open,
R27, R60 = open, L3 = open