LTC6945
5
6945f
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TC = 25°C. VREF+ = 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
–156
–157
–158
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 ≤ (VCP+ – 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.
Note 7: Reference frequency supplied by Wenzel 501-04608A,
fREF = 10MHz, PREF = 13dBm.
Note 8: Output phase noise floor is calculated from normalized phase
noise floor by LM(OUT) = –226 + 10log10(fPFD) + 20log10(fRF/fPFD).
Note 9: Output 1/f phase noise is calculated from normalized 1/f phase
noise by LM(OUT –1/f) = –274 + 20log10 (fRF) – 10log10 (fOFFSET).
Note 10: ICP = 11.2mA, fPFD = 250kHz, fRF = 914MHz, FILT[1:0] = 3, Loop
BW = 7kHz.
Note 11: Measured using DC1649A.
TYPICAL PERFORMANCE CHARACTERISTICS
REF Input Sensitivity vs
Frequency
REFO Output Power vs Frequency
REFO Phase Noise
FREQUENCY (MHz)
0
SENSITIVITY
(dBm)
–35
–30
–25
200 225
6945 G01
–40
–45
–55
50
100
150
25
250
75
125
175
–50
–15
–20
105°C
25°C
–40°C
BST = 1
FILT = 0
FREQUENCY (MHz)
0
P
OUT
(dBm)
0
1
2
200 225
6945 G02
–1
–2
–4
50
100
150
25
250
75
125
175
–3
4
3
105°C
25°C
–40°C
OFFSET FREQUENCY (Hz)
–155
PHASE
NOISE
(dBc/Hz)
–150
–145
–140
100
10k
100k
1M
5M
6945 G03
–160
1k
POUT = 1.45dBm
fREF = 10MHz
BST = 1
FILT = 3
NOTE 7