LTC6945 - Ultralow Noise and Spurious 0.35GHz to 6GHz Integer-N ...

ELECTRICAL CHARACTERISTICS
LTC6945
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TC = 25°C. V +
REF = VREF0
+ = VD
+ = VRF
+ = VVCO
+ = 3.3V, VCP
+ = 5V unless otherwise
specified. All voltages are with respect to GND.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Phase Noise and Spurious
LM(MIN) Output Phase Noise Floor (Note 5) RFO[1:0] = 3, OD[2:0] = 1, fRF = 6GHz
RFO[1:0] = 3, OD[2:0] = 2, fRF = 3GHz
RFO[1:0] = 3, OD[2:0] = 3, fRF = 2GHz
RFO[1:0] = 3, OD[2:0] = 4, fRF = 1.5GHz
RFO[1:0] = 3, OD[2:0] = 5, fRF = 1.2GHz
RFO[1:0] = 3, OD[2:0] = 6, fRF = 1.0GHz
–155
–155
–156
–156
–157
–158
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
LM(NORM) Normalized In-Band Phase Noise Floor ICP = 11.2mA (Notes 6, 7, 8) –226 dBc/Hz
LM(NORM –1/f) Normalized In-Band 1/f Phase Noise ICP = 11.2mA (Notes 6, 9) –274 dBc/Hz
LM(IB) In-Band Phase Noise Floor (Notes 6, 7, 8, 10) –99 dBc/Hz
Integrated Phase Noise from 100Hz to
40MHz
(Notes 4, 7, 10) 0.13 °RMS
Spurious Reference Spur, PLL locked (Notes 4, 7, 10, 11) –102 dBc
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC6945I is guaranteed to meet the specified performance
limits over the –40°C to 105°C case temperature range.
Note 3: For 0.8V ≤ VCP ≤ (V +
CP – 0.8V).
Note 4: VCO is Crystek CVCO55CL-0902-0928.
Note 5: fVCO = 6GHz, fOFFSET = 40MHz.
Note 6: Measured inside the loop bandwidth with the loop locked.
TYPICAL PERFORMANCE CHARACTERISTICS
SENSITIVITY (dBm)
–15
–20
–25
–30
–35
–40
–45
–50
–55
0
Note 7: Reference frequency supplied by Wenzel 501-04608A,
fREF = 10MHz, P REF = 13dBm.
Note 8: Output phase noise floor is calculated from normalized phase
noise floor by LM(OUT) = –226 + 10log 10(f PFD) + 20log 10(f RF/f PFD).
Note 9: Output 1/f phase noise is calculated from normalized 1/f phase
noise by L M(OUT –1/f) = –274 + 20log 10 (f RF) – 10log 10 (f OFFSET).
Note 10: I CP = 11.2mA, f PFD = 250kHz, f RF = 914MHz, FILT[1:0] = 3, Loop
BW = 7kHz.
Note 11: Measured using DC1649A.
REF Input Sensitivity vs
Frequency REFO Output Power vs Frequency REFO Phase Noise
BST = 1
FILT = 0
105°C
25°C
–40°C
25 50 75 100 125 150 175 200 225 250
FREQUENCY (MHz)
6945 G01
POUT (dBm)
4
3
2
1
0
–1
–2
–3
–4
0
25 50 75 100 125 150 175 200 225 250
FREQUENCY (MHz)
105°C
25°C
–40°C
6945 G02
PHASE NOISE (dBc/Hz)
–140
–145
–150
–155
P OUT = 1.45dBm
fREF = 10MHz
BST = 1
FILT = 3
NOTE 7
–160
100 1k 10k 100k 1M 5M
OFFSET FREQUENCY (Hz)
6945 G03
6945f
5