LT5518EUF [Linear]

1.5GHz - 2.4GHz High Linearity Direct Quadrature Modulator; 的1.5GHz - 2.4GHz高线性度直接正交调制器
LT5518EUF
型号: LT5518EUF
厂家: Linear    Linear
描述:

1.5GHz - 2.4GHz High Linearity Direct Quadrature Modulator
的1.5GHz - 2.4GHz高线性度直接正交调制器

射频调制器 射频解调器 微波调制器 微波解调器 射频和微波
文件: 总16页 (文件大小:374K)
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LT5518  
1.5GHz–2.4GHz  
High Linearity Direct  
Quadrature Modulator  
U
DESCRIPTIO  
FEATURES  
The LT®5518 is a direct I/Q modulator designed for high  
performance wireless applications, including wireless  
infrastructure. It allows direct modulation of an RF signal  
usingdifferentialbasebandIandQsignals.ItsupportsPHS,  
GSM, EDGE, TD-SCDMA, CDMA, CDMA2000, W-CDMA  
and other systems. It may also be configured as an image  
reject up-converting mixer, by applying 90° phase-shifted  
signals to the I and Q inputs. The high impedance I/Q  
baseband inputs consist of voltage-to-current converters  
that in turn drive double-balanced mixers. The outputs of  
these mixers are summed and applied to an on-chip RF  
transformer, which converts the differential mixer signals  
to a 50Ω single-ended output. The balanced I and Q  
baseband input ports are intended for DC coupling from a  
source with a common mode voltage level of about 2.1V.  
The LO path consists of an LO buffer with single-ended  
input, and precision quadrature generators that produce  
the LO drive for the mixers. The supply voltage range is  
4.5V to 5.25V.  
High Input Impedance Version of the LT5528  
Direct Conversion to 1.5GHz – 2.4GHz  
High OIP3: 22.8dBm at 2GHz  
Low Output Noise Floor at 20MHz Offset:  
No RF: 158.2dBm/Hz  
P
OUT  
= 4dBm: 152.5dBm/Hz  
4-Ch W-CDMA ACPR: 64dBc at 2.14GHz  
Integrated LO Buffer and LO Quadrature Phase  
Generator  
50Ω AC-Coupled Single-Ended LO and RF Ports  
Low Carrier Leakage: 49dBm at 2GHz  
High Image Rejection: 40dB at 2GHz  
16-Lead QFN 4mm × 4mm Package  
U
APPLICATIO S  
Infrastructure Tx for DCS, PCS and UMTS Bands  
Image Reject Up-Converters for DCS, PCS and UMTS  
Bands  
Low Noise Variable Phase-Shifter for 1.5GHz to  
, LTC and LT are registered trademarks of Linear Technology Corporation.  
All other trademarks are the property of their respective owners.  
2.4GHz Local Oscillator Signals  
U
TYPICAL APPLICATIO  
1.5GHz to 2.4GHz Direct Conversion Transmitter Application  
with LO Feedthrough and Image Calibration Loop  
W-CDMA ACPR, AltCPR and Noise vs RF Output  
Power at 2140MHz for 1 and 4 Channels  
5V  
100nF  
×2  
V
CC 8, 13  
–55  
–60  
–65  
–70  
–75  
–80  
–85  
–135  
–140  
–145  
–150  
–155  
–160  
–165  
4-CH ACPR  
LT5518  
14  
16  
RF = 1.5GHz  
TO 2.4GHz  
I-DAC  
V-I  
I-CHANNEL  
4-CH ALTCPR  
1-CH ACPR  
11  
PA  
0°  
1
EN  
90°  
LO FEEDTHROUGH  
CAL OUT  
BALUN  
Q-CHANNEL  
V-I  
7
5
Q-DAC  
1-CH ALTCPR  
IMAGE CAL OUT  
1-CH NOISE  
CAL  
4-CH NOISE  
BASEBAND  
GENERATOR  
3
VCO/SYNTHESIZER  
2, 4, 6, 9, 10, 12, 15, 17  
DOWNLINK TEST MODEL 64 DPCH  
–34 –30 –26 –22 –18 –14 –10  
RF OUTPUT POWER PER CARRIER (dBm)  
5518 TA01b  
ADC  
5518 TA01a  
5518f  
1
LT5518  
W W U W  
U
W
U
ABSOLUTE AXI U RATI GS  
PACKAGE/ORDER I FOR ATIO  
(Note 1)  
TOP VIEW  
ORDER PART  
NUMBER  
Supply Voltage.........................................................5.5V  
Common Mode Level of BBPI, BBMI and  
BBPQ, BBMQ .......................................................2.5V  
Operating Ambient Temperature  
16 15 14 13  
LT5518EUF  
EN  
GND  
LO  
1
2
3
4
12 GND  
11 RF  
17  
(Note 2) .............................................. 40°C to 85°C  
Storage Temperature Range.................. 65°C to 125°C  
Voltage on Any Pin  
GND  
GND  
10  
9
GND  
UF PART  
MARKING  
5
6
7
8
Not to Exceed...................... 500mV to V + 500mV  
CC  
5518  
T
JMAX  
= 125°C, θ = 37°C/W  
JA  
EXPOSED PAD (PIN 17) IS GND  
MUST BE SOLDERED TO THE PCB  
Consult LTC Marketing for parts specified with wider operating temperature ranges.  
ELECTRICAL CHARACTERISTICS VCC = 5V, EN = High, TA = 25°C, fLO = 2GHz, fRF = 2.002GHz, PLO = 0dBm.  
BBPI, BBMI, BBPQ, BBMQ inputs 2.06VDC, Baseband Input Frequency = 2MHz, I and Q 90° shifted (upper sideband selection).  
PRF, OUT = 10dBm, unless otherwise noted. (Note 3)  
SYMBOL  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
RF Output (RF)  
f
RF Frequency Range  
RF Frequency Range  
3dB Bandwidth  
–1dB Bandwidth  
1.5 to 2.4  
1.7 to 2.2  
GHz  
GHz  
RF  
S
S
RF Output Return Loss  
RF Output Return Loss  
RF Output Noise Floor  
EN = High (Note 6)  
EN = Low (Note 6)  
–14  
–12  
dB  
dB  
22, ON  
22, OFF  
NFloor  
No Input Signal (Note 8)  
–158.2  
–152.5  
–151.1  
dBm/Hz  
dBm/Hz  
dBm/Hz  
P
P
= 4dBm (Note 9)  
= 4dBm (Note 10)  
OUT  
OUT  
G
G
Conversion Power Gain  
Conversion Voltage Gain  
Absolute Output Power  
3 • LO Conversion Gain Difference  
Output 1dB Compression  
Output 2nd Order Intercept  
Output 3rd Order Intercept  
Image Rejection  
P
/P , I&Q  
10.6  
–4  
dB  
dB  
P
OUT IN  
20 • log(V  
/V  
)
V
OUT, 50Ω IN, DIFF, I or Q  
P
1V  
CW Signal, I and Q  
0
dBm  
dB  
OUT  
P-P, DIFF  
G
(Note 17)  
(Note 7)  
28  
8.5  
49  
3LO vs LO  
OP1dB  
OIP2  
OIP3  
IR  
dBm  
dBm  
dBm  
dBc  
(Notes 13, 14)  
(Notes 13, 15)  
(Note 16)  
22.8  
40  
LOFT  
Carrier Leakage  
(LO Feedthrough)  
EN = High, P = 0dBm (Note 16)  
49  
58  
dBm  
dBm  
LO  
EN = Low, P = 0dBm (Note 16)  
LO  
LO Input (LO)  
f
LO Frequency Range  
LO Input Power  
1.5 to 2.4  
0
GHz  
dBm  
dB  
LO  
P
S
S
–10  
5
LO  
LO Input Return Loss  
LO Input Return Loss  
LO Input Referred Noise Figure  
LO to RF Small Signal Gain  
LO Input Linearity  
EN = High (Note 6)  
EN = Low (Note 6)  
(Note 5) at 2GHz  
(Note 5) at 2GHz  
(Note 5) at 2GHz  
–18  
–5  
11, ON  
11, OFF  
dB  
NF  
14  
dB  
LO  
G
23.8  
–9  
dB  
LO  
IIP3  
dBm  
LO  
5518f  
2
LT5518  
ELECTRICAL CHARACTERISTICS VCC = 5V, EN = High, TA = 25°C, fLO = 2GHz, fRF = 2.002GHz, PLO = 0dBm.  
BBPI, BBMI, BBPQ, BBMQ inputs 2.06VDC, Baseband Input Frequency = 2MHz, I and Q 90° shifted (upper sideband selection).  
PRF, OUT = 10dBm, unless otherwise noted. (Note 3)  
SYMBOL  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
Baseband Inputs (BBPI, BBMI, BBPQ, BBMQ)  
BW  
Baseband Bandwidth  
3dB Bandwidth  
400  
2.06  
MHz  
V
BB  
V
DC Common Mode Voltage  
Differential Input Resistance  
Common Mode Input Resistance  
(Note 4)  
CMBB  
R
R
Between BBPI and BBMI (or BBPQ and BBMQ)  
BBPX and BBMX Shorted Together  
2.9  
kΩ  
Ω
IN, DIFF  
IN, CM  
105  
I
Common Mode Compliance Current Range BBPX and BBMX Shorted Together (Note 18)  
730 to 480  
40  
µA  
CM, COMP  
P
Carrier Feedthrough on BB  
Input 1dB Compression Point  
I/Q Absolute Gain Imbalance  
I/Q Absolute Phase Imbalance  
P
= 0 (Note 4)  
OUT  
dBm  
LO2BB  
IP1dB  
Differential Peak-to-Peak (Note 7)  
2.7  
V
P-P, DIFF  
ΔG  
0.06  
dB  
I/Q  
I/Q  
Δφ  
1
deg  
Power Supply (V  
)
CC  
V
Supply Voltage  
4.5  
1.0  
5
5.25  
145  
50  
V
mA  
µA  
µs  
CC  
I
I
t
t
Supply Current  
EN = High  
128  
0.05  
0.2  
CC, ON  
CC, OFF  
ON  
Supply Current, Sleep Mode  
Turn-On Time  
EN = 0V  
EN = Low to High (Note 11)  
EN = High to Low (Note 12)  
Turn-Off Time  
1.3  
µs  
OFF  
Enable (EN), Low = Off, High = On  
Enable  
Input High Voltage  
Input High Current  
EN = High  
EN = 5V  
V
µA  
240  
Sleep  
Input Low Voltage  
EN = Low  
0.5  
V
Note 1: Absolute Maximum Ratings are those values beyond which the life  
of a device may be impaired.  
Note 13: Baseband is driven by 2MHz and 2.1MHz tones. Drive level is set  
in such a way that the two resulting RF output tones are –10dBm each.  
Note 2: Specifications over the 40°C to 85°C temperature range are  
assured by design, characterization and correlation with statistical process  
controls.  
Note 3: Tests are performed as shown in the configuration of Figure 8.  
Note 4: On each of the four baseband inputs BBPI, BBMI, BBPQ and  
BBMQ.  
Note 14: IM2 measured at LO frequency + 4.1MHz.  
Note 15: IM3 measured at LO frequency + 1.9MHz and LO frequency +  
2.2MHz.  
Note 16: Amplitude average of the characterization data set without image  
or LO feedthrough nulling (unadjusted).  
Note 17: The difference in conversion gain between the spurious signal at  
f = 3 • LO – BB versus the conversion gain at the desired signal at f = LO +  
BB for BB = 2MHz and LO = 2GHz.  
Note 5: V(BBPI) – V(BBMI) = 1V , V(BBPQ) – V(BBMQ) = 1V  
.
DC  
DC  
Note 6: Maximum value within –1dB bandwidth.  
Note 18: Common mode current range where the common mode (CM)  
feedback loop biases the part properly. The common mode current is the  
sum of the current flowing into the BBPI (or BBPQ) pin and the current  
flowing into the BBMI (or BBMQ) pin.  
Note 7: An external coupling capacitor is used in the RF output line.  
Note 8: At 20MHz offset from the LO signal frequency.  
Note 9: At 20MHz offset from the CW signal frequency.  
Note 10: At 5MHz offset from the CW signal frequency.  
Note 11: RF power is within 10% of final value.  
Note 12: RF power is at least 30dB lower than in the ON state.  
5518f  
3
LT5518  
U W  
VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz,  
TYPICAL PERFOR A CE CHARACTERISTICS  
P
LO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 2.06VDC, Baseband Input Frequency fBB = 2MHz, I and Q 90° shifted without image or  
LO feedthrough nulling. fRF = fBB + fLO (upper sideband selection). PRF, OUT = 10dBm (–10dBm/tone for 2-tone measurements), unless  
otherwise noted. (Note 3)  
Voltage Gain and Output 1dB  
RF Output Power vs LO Frequency  
at 1VP-P Differential Baseband Drive  
Compression vs LO Frequency  
and Temperature  
Supply Current vs Supply Voltage  
140  
130  
120  
110  
100  
5
0
15  
10  
5
4.5V  
5.5V  
5V  
T
= 85°C  
A
OP1dB  
GAIN  
T
= 25°C  
A
–5  
0
T
= –40°C  
A
–5  
–10  
–15  
5V, T = –40°C  
A
–10  
–15  
5V, T = 25°C  
A
5V, T = 85°C  
A
4.5V, T = 25°C  
A
5.5V, T = 25°C  
A
5.0  
1.3  
1.5 1.7 1.9 2.1 2.3 2.5 2.7  
1.3  
1.5 1.7 1.9 2.1 2.3 2.5 2.7  
4.5  
5.5  
SUPPLY VOLTAGE (V)  
LO FREQUENCY (GHz)  
LO FREQUENCY (GHz)  
5518 G01  
5518 G02  
5518 G03  
Voltage Gain and Output 1dB  
Compression vs LO Frequency  
and Supply Voltage  
Output IP3 and Noise Floor vs LO  
Frequency and Temperature  
Output IP3 and Noise Floor vs LO  
Frequency and Supply Voltage  
26  
24  
22  
20  
18  
16  
–146  
–148  
–150  
–152  
–154  
–156  
–158  
–160  
–162  
–164  
–166  
26  
24  
22  
20  
18  
16  
–146  
–148  
–150  
–152  
–154  
–156  
–158  
–160  
–162  
–164  
–166  
15  
10  
OIP3  
T
T
T
= 40°C  
= 85°C  
= 25°C  
OIP3  
4.5V  
5.5V  
5V  
A
A
A
4.5V  
5.5V  
5V  
OP1dB  
f
f
= 2MHz  
= 2.1MHz  
f
f
= 2MHz  
= 2.1MHz  
BB, 1  
BB, 2  
BB, 1  
BB, 2  
5
0
14 NOISE FLOOR  
14 NOISE FLOOR  
GAIN  
–5  
10  
15  
12  
10  
12  
10  
NO BASEBAND SIGNAL  
= 2.14GHz (FIXED) FOR NOISE  
NO BASEBAND SIGNAL  
f = 2.14GHz (FIXED) FOR NOISE  
LO  
8
6
8
6
f
LO  
2.1  
LO FREQUENCY (GHz)  
2.5  
2.7  
2.1  
LO/NOISE FREQUENCY (GHz)  
2.5  
2.7  
2.1  
LO/NOISE FREQUENCY (GHz)  
2.5  
2.7  
1.3 1.5  
1.7 1.9  
2.3  
1.3 1.5  
1.7 1.9  
2.3  
1.3 1.5  
1.7 1.9  
2.3  
5518 G04  
5518 G05  
5518 G06  
LO Feedthrough to RF Output vs  
LO Frequency  
2 • LO Leakage to RF Output vs  
2 • LO Frequency  
3 • LO Leakage to RF Output vs  
3 • LO Frequency  
30  
35  
40  
45  
50  
55  
60  
65  
–70  
25  
30  
35  
40  
45  
50  
55  
40  
45  
50  
55  
60  
5V, T = 40°C  
A
5V, T = 25°C  
A
5V, T = 85°C  
A
4.5V, T = 25°C  
A
5.5V, T = 25°C  
A
5V, T = 40°C  
5V, T = 40°C  
A
A
5V, T = 25°C  
5V, T = 25°C  
A
A
5V, T = 85°C  
5V, T = 85°C  
A
A
4.5V, T = 25°C  
4.5V, T = 25°C  
A
A
5.5V, T = 25°C  
5.5V, T = 25°C  
A
A
4.5  
5.1 5.7 6.3 6.9  
8.1  
2.1  
LO FREQUENCY (GHz)  
2.5  
2.7  
3.9  
7.5  
1.3 1.5  
1.7 1.9  
2.3  
4.2  
2 • LO FREQUENCY (GHz)  
5.0  
5.4  
2.6 3.0  
3.4 3.8  
4.6  
3 • LO FREQUENCY (GHz)  
5518 G09  
5518 G07  
5518 G08  
5518f  
4
LT5518  
U W  
TYPICAL PERFOR A CE CHARACTERISTICS  
VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz,  
P
LO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 2.06VDC, Baseband Input Frequency fBB = 2MHz, I and Q 90° shifted without image  
or LO feedthrough nulling. fRF = fBB + fLO (upper sideband selection). PRF, OUT = 10dBm (–10dBm/tone for 2-tone measurements),  
unless otherwise noted. (Note 3)  
Absolute I/Q Gain Imbalance  
vs LO Frequency  
Absolute I/Q Phase Imbalance  
vs LO Frequency  
Image Rejection vs LO Frequency  
–25  
–30  
–35  
–40  
–45  
–50  
–55  
02  
0.1  
0
5
4
3
2
1
0
5V, T = 40°C  
5V, T = 40°C  
A
A
5V, T = 25°C  
5V, T = 25°C  
A
A
5V, T = 85°C  
5V, T = 85°C  
A
A
4.5V, T = 25°C  
4.5V, T = 25°C  
A
A
5.5V, T = 25°C  
5.5V, T = 25°C  
A
A
5V, T = 40°C  
A
5V, T = 25°C  
A
5V, T = 85°C  
A
4.5V, T = 25°C  
A
5.5V, T = 25°C  
A
1.5 1.7 1.9 2.1  
2.7  
1.5 1.7 1.9 2.1  
2.7  
1.5 1.7 1.9 2.1  
LO FREQUENCY (GHz)  
2.7  
1.3  
2.3 2.5  
1.3  
2.3 2.5  
1.3  
2.3 2.5  
LO FREQUENCY (GHz)  
LO FREQUENCY (GHz)  
5518 G10  
5518 G11  
5518 G12  
RF CW Output Power, HD2 and HD3 vs  
Baseband Voltage and Temperature  
Voltage Gain vs LO Power  
Output IP3 vs LO Power  
–2  
–4  
24  
22  
20  
18  
16  
14  
12  
10  
8
10  
20  
30  
40  
50  
60  
70  
10  
0
RF  
HD3  
HD2  
–6  
T
T
T
= 40°C  
= 85°C  
= 25°C  
A
A
A
10  
–8  
–10  
–12  
–14  
–16  
–18  
20  
30  
40  
50  
5V, T = 40°C  
5V, T = 40°C  
A
A
5V, T = 25°C  
5V, T = 25°C  
HD2 = MAX POWER AT  
+ 2 • f OR f – 2 • f  
A
A
A
5V, T = 85°C  
5V, T = 85°C  
f
A
LO  
BB  
LO  
BB  
4.5V, T = 25°C  
4.5V, T = 25°C  
HD3 = MAX POWER AT  
A
A
A
A
6
5.5V, T = 25°C  
5.5V, T = 25°C  
f
+ 3 • f OR f – 3 • f  
LO  
BB  
LO  
BB  
5
4
–16 –12 8 –4  
0
8
–16 –12 8 –4  
0
8
–20  
4
–20  
4
0
2
3
4
1
I AND Q BASEBAND VOLTAGE (V  
)
LO INPUT POWER (dBm)  
LO INPUT POWER (dBm)  
P-P, DIFF  
5518 G13  
5518 G14  
5518 G15  
RF CW Output Power, HD2 and  
HD3 vs Baseband Voltage and  
Supply Voltage  
LO Feedthrough to RF Output and  
Image Rejection vs Baseband  
Voltage and Temperature  
LO Feedthrough to RF Output and  
Image Rejection vs Baseband  
Voltage and Supply Voltage  
10  
20  
30  
40  
50  
60  
70  
10  
25  
25  
30  
35  
40  
45  
50  
55  
T
T
T
= 40°C  
= 85°C  
= 25°C  
A
A
A
4.5V  
LO FT  
5.5V  
5V  
LO FT  
0
30  
35  
40  
45  
50  
55  
RF  
HD3  
4.5V  
5.5V  
5V  
10  
20  
30  
40  
50  
HD2  
IR  
HD2 = MAX POWER AT  
IR  
f
+ 2 • f OR f – 2 • f  
LO  
BB LO  
BB  
HD3 = MAX POWER AT  
f
LO  
+ 3 • f OR f – 3 • f  
BB  
LO  
BB  
5
0
2
3
4
0
2
3
4
5
0
2
3
4
5
1
1
1
I AND Q BASEBAND VOLTAGE (V  
)
I AND Q BASEBAND VOLTAGE (V  
)
I AND Q BASEBAND VOLTAGE (V  
)
P-P, DIFF  
P-P, DIFF  
P-P, DIFF  
5518 G16  
5518 G17  
5518 G18  
5518f  
5
LT5518  
U W  
VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz,  
TYPICAL PERFOR A CE CHARACTERISTICS  
P
LO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 2.06VDC, Baseband Input Frequency fBB = 2MHz, I and Q 90° shifted without image  
or LO feedthrough nulling. fRF = fBB + fLO (upper sideband selection). PRF, OUT = 10dBm (–10dBm/tone for 2-tone measurements),  
unless otherwise noted. (Note 3)  
LO and RF Port Return Loss  
vs RF Frequency  
Output IP2 vs LO Frequency  
65  
60  
55  
50  
45  
40  
35  
0
–10  
–20  
–30  
–40  
–50  
f
f
f
= 2MHz  
BB,1  
BB,2  
LO PORT, EN = LOW  
= 2.1MHz  
= f  
+ f  
+ f  
IM2 BB,1 BB,2 LO  
LO PORT,  
EN = HIGH  
RF PORT, EN =  
HIGH, NO LO  
RF PORT, EN = HIGH,  
5V, T = 40°C  
A
P
LO  
= 0dBm  
RF PORT,  
EN = LOW  
5V, T = 25°C  
A
5V, T = 85°C  
A
4.5V, T = 25°C  
5.5V, T = 25°C  
A
A
2.1  
2.5  
2.7  
2.1  
RF FREQUENCY (GHz)  
2.5  
2.7  
1.3 1.5  
1.7 1.9  
2.3  
1.3 1.5  
1.7 1.9  
2.3  
LO FREQUENCY (GHz)  
5518 G19  
5518 G20  
U
U
U
PI FU CTIO S  
EN (Pin 1): Enable Input. When the enable pin voltage is  
higher than 1V, the IC is turned on. When the input voltage  
is less than 0.5V, the IC is turned off.  
biased at about 2.06V. Applied common mode voltage  
must stay below 2.5V.  
V
CC  
(Pins 8, 13): Power Supply. Pins 8 and 13 are con-  
GND (Pins 2, 4, 6, 9, 10, 12, 15): Ground. Pins 6, 9, 15  
and17(exposedpad)areconnectedtoeachotherinternally.  
Pins 2 and 4 are connected to each other internally and  
function as the ground return for the LO signal. Pins 10  
and 12 are connected to each other internally and function  
as the ground return for the on-chip RF balun. For best RF  
performance, pins 2, 4, 6, 9, 10, 12, 15 and the Exposed  
Pad (Pin 17) should be connected to the printed circuit  
board ground plane.  
nected to each other internally. It is recommended to use  
0.1µF capacitors for decoupling to ground on each of  
these pins.  
RF (Pin 11): RF Output. The RF output is an AC-coupled  
single-ended output with approximately 50Ω output im-  
pedance at RF frequencies. Externally applied DC voltage  
should be within the range –0.5V to V + 0.5V in order  
CC  
to avoid turning on ESD protection diodes.  
BBPI,BBMI(Pins14,16):BasebandInputsfortheI-Chan-  
nel, with 2.9kΩ Differential Input Impedance. Internally  
biased at about 2.06V. Applied common mode voltage  
must stay below 2.5V.  
LO(Pin3):LOInput.TheLOinputisanAC-coupledsingle-  
ended input with approximately 50Ω input impedance at  
RF frequencies. Externally applied DC voltage should be  
within the range 0.5V to V + 0.5V in order to avoid  
CC  
Exposed Pad (Pin 17): Ground. This pin must be soldered  
to the printed circuit board ground plane.  
turning on ESD protection diodes.  
BBPQ,BBMQ(Pins7,5):BasebandInputsfortheQ-Chan-  
nel, with 2.9kΩ Differential Input Impedance. Internally  
5518f  
6
LT5518  
W
BLOCK DIAGRA  
V
CC  
8
13  
LT5518  
BBPI 14  
BBMI 16  
V-I  
V-I  
11 RF  
0°  
90°  
BALUN  
BBPQ  
BBMQ  
7
5
1
EN  
2
4
6
9
3
10  
12  
15  
17  
5518 BD  
GND  
LO  
GND  
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APPLICATIO S I FOR ATIO  
The LT5518 consists of I and Q input differential voltage-  
to-current converters, I and Q up-conversion mixers, an  
RF output balun, an LO quadrature phase generator and  
LO buffers.  
in an RF output balun, which also transforms the output  
impedance to 50Ω. The center frequency of the resulting  
RF signal is equal to the LO signal frequency. The LO in-  
put drives a phase shifter which splits the LO signal into  
in-phase and quadrature LO signals. These LO signals  
are then applied to on-chip buffers which drive the up-  
conversion mixers. Both the LO input and RF output are  
single-ended, 50Ω-matched and AC coupled.  
External I and Q baseband signals are applied to the dif-  
ferential baseband input pins, BBPI, BBMI, and BBPQ,  
BBMQ.Thesevoltagesignalsareconvertedtocurrentsand  
translated to RF frequency by means of double-balanced  
up-converting mixers. The mixer outputs are combined  
LT5518  
RF  
= 5V  
C
V
CC  
BALUN  
FROM  
Q
LOMI  
LOPI  
200  
BBPI  
V
= 500mV  
CM  
REF  
1.3k  
1.3k  
1.8pF  
1.8pF  
200Ω  
BBMI  
5518 F01  
GND  
Figure 1. Simplified Circuit Schematic of the LT5518 (Only I-Half is Drawn)  
5518f  
7
LT5518  
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Baseband Interface  
DAC’s differential output current to minimize the LO to RF  
feedthrough. Resistors R3A, R3B, R4A and R4B translate  
The baseband inputs (BBPI, BBMI), (BBPQ, BBMQ) pres-  
ent a differential input impedance of about 2.9kΩ. At each  
of the four baseband inputs, a lowpass filter using 200Ω  
and 1.8pF to ground is incorporated (see Figure 1), which  
limits the baseband bandwidth to approximately 250MHz  
the DAC’s output common mode level from about 0.5V  
DC  
to the LT5518’s input at about 2.06V . For these resis-  
DC  
tors, 1% accuracy is recommended. For different ambi-  
ent temperatures, the LT5518 input common mode level  
varies with a temperature coefficient of about –2.7mV/°C.  
The internal common mode feedback loop will correct  
these level changes in order to bias the LT5518 at the  
correct operating point. Resistors R3 and R4 are chosen  
high enough that the LT5518 common mode compliance  
current value will not be exceeded at the inputs of the  
LT5518 as a result of temperature shifts. Capacitors C4A  
and C4B minimize the input signal attenuation caused by  
the network R3A, R3B, R4A and R4B. This results in a  
gaindifferencebetweenlowfrequencyandhighfrequency  
baseband signals. The high frequency baseband 3dB  
corner point is approximately given by:  
(1dB point). The common mode voltage is about 2.06V  
o
and is slightly temperature dependent. At T = 40 C, the  
A
o
common mode voltage is about 2.19V and at T = 85 C  
A
it is about 1.92V.  
If the I/Q signals are DC-coupled to the LT5518, it is  
important that the applied common mode voltage level  
of the I and Q inputs is about 2.06V in order to properly  
bias the LT5518. Some I/Q test generators allow setting  
thecommonmodevoltageindependently. Inthiscase, the  
common mode voltage of those generators must be set  
to 1.03V to match the LT5518 internal bias, because for  
DC signals, there is no 6dB source-load voltage division  
(see Figure 2).  
f
= 1/[2π • C4A • (R3A||R4A||(R  
/2)]  
–3dB  
IN, DIFF  
In this example, f  
= 58kHz.  
–3dB  
50Ω  
50Ω  
1.5k  
Thiscornerpointshouldbesetsignificantlylowerthanthe  
minimum baseband signal frequency by choosing large  
enough capacitors C4A and C4B. For signal frequencies  
1.03V  
2.06V  
DC  
DC  
+
+
+
2.06V  
DC  
2.06V  
2.06V  
DC  
DC  
50Ω  
significantly lower than f  
proximately  
, the gain is reduced by ap-  
GENERATOR  
GENERATOR  
LT5518  
–3dB  
5518 F02  
Figure 2. DC Voltage Levels for a Generator Programmed at  
1.03VDC for a 50Ω Load and for the LT5518 as a Load  
G
DC  
= 20 • log [R3A||(R  
/2)]/[R3A||(R  
/2)  
IN, DIFF  
IN, DIFF  
+ R4A]  
In this example, G = –11dB.  
The LT5518 should be driven differentially; otherwise, the  
even-order distortion products will degrade the overall  
linearityseverely. Typically, aDACwillbethesignalsource  
for the LT5518. A reconstruction filter should be placed  
between the DAC output and the LT5518’s baseband  
inputs. DC coupling between the DAC outputs and the  
LT5518 baseband inputs is recommended. Active level  
shifters may be required to adapt the common mode level  
of the DAC outputs to the common mode input voltage  
of the LT5518. It is also possible to achieve a DC level  
shift with passive components, depending on the appli-  
cation. For example, if flat frequency response to DC is  
not required, then the interface circuit of Figure 3 may be  
used. This figure shows a commonly used 0mA – 20mA  
DAC output followed by a passive 5th order lowpass  
filter. The DC-coupled interface allows adjustment of the  
DC  
Inserting the network of R3A, R3B, R4A, R4B, C4A and  
C4B has the following consequences:  
• Reduced LO feedthrough adjustment range. LO to RF  
feedthroughcanbereducedbyadjustingthedifferential  
DC offset voltage applied to the I and/or Q inputs. Be-  
causeoftheDCgainreduction,therangeofadjustment  
is reduced. The resolution of the offset adjustment is  
improved by the same gain reduction factor.  
• DC notch for uneven number of channels. The interface  
drawn in Figure 3 might not be practical for an uneven  
number of channels, since the gain at DC is lower and  
will appear in the center of (one of) the channel(s). In  
thatcase,aDC-coupledlevelshiftingcircuitisrequired,  
or the LT5528 might be a better solution.  
5518f  
8
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• Introduction of a (low frequency) time constant dur-  
ing startup. For TDMA-like systems the time constant  
introduced by C4A and C4B can cause some delay  
during start-up. The associated time constant is ap-  
will increase the voltage on the DAC output by dumping  
an extra current into resistors R1A, R1B, R2A and R2B.  
This current is about (V – V )/(R3A + R4A) = (5  
CC  
DAC  
– 0.5)/(3.01k + 5.63k) = 0.52mA. Maximum impedance  
proximately given by T = R  
• (C4A + C4B). In  
to ground will then be V  
/(I  
+ I ) = 1.25/0.02052  
D
IN, CM  
COMPL MAX LS  
this example it will result in a delay of about T = 105  
= 60.9Ω.  
D
• 6.6n = 693ns.  
4. Reflection of out-of-band baseband signal power. DAC  
outputsignalcomponentshigherthanthecut-offfrequency  
of the lowpass filter will not see R2A and R2B as load  
resistors and therefore will see only R1A, R1B and the  
filter components as a load. Therefore, it is important to  
start the lowpass filter with a capacitor (C1), in order to  
shunttheDAChigherfrequencycomponentsandthereby,  
limit the required extra voltage headroom.  
ThemaximumsinusoidalsinglesidebandRFoutputpower  
is about 5.5dBm for a full 0mA to 20mA DAC swing.  
This maximum RF output level is usually limited by the  
compliance voltage range of the DAC (V  
) which is  
COMPL  
assumed here to be 1.25V. When the DAC output voltage  
swingislargerthanthiscompliancevoltage,thebaseband  
signal will distort and linearity requirements usually will  
not be met. The following situations can cause the DAC’s  
compliance voltage limit to be exceeded:  
The LT5518’s output 1dB compression point is about  
8.5dBm, and with the interface network described above,  
a common DAC cannot drive the part into compression.  
However, it is possible to increase the driving capability  
by using a negative supply voltage. For example, if a –1V  
supply is available, resistors R1A, R1B, R2A and R2B  
can be made 200Ω each and connected with one side to  
the –1V supply instead of ground. Typically, the voltage  
compliancerangeoftheDACis1Vto1.25V, sotheDAC’s  
outputvoltagewillstaywithinthisrange.Almost6dBextra  
voltage swing is available, thus enabling the DAC to drive  
the LT5518 beyond its 1dB compression point. Resistors  
R3A, R3B, R4A, R4B and the lowpass filter components  
must be adjusted for this case.  
1. Too high DAC load impedance. If the DC impedance to  
ground is higher than V  
/I  
= 1.25/0.02 = 62.5Ω,  
COMPL MAX  
thecompliancevoltageisexceededforafullDACswing.In  
Figure3, two100Ωresistorsinparallelareused, resulting  
in a DC impedance to ground of 50Ω.  
2. Too much DC offset. In some DACs, an additional DC  
offset current can be set. For example, if the maximum  
offset current is set to I  
/8 = 2.5mA, then the maxi-  
MAX  
mum DC DAC load impedance to ground is reduced to  
/I • (1 + 1/8) = 1.25/0.0225 = 55Ω.  
V
COMPL MAX  
3. DC shift caused by R3A, R3B, R4A and R4B if used. The  
DC shift network consisting of R3A, R3B, R4A and R4B  
LT5518  
RF = 5.5dBm, MAX  
V
CC  
C
5V  
BALUN  
FROM  
Q
LOMI  
C4A  
3.3nF  
LOPI  
L1A  
L2A  
0.53V  
200Ω  
DC  
BBPI  
2.1V  
V
REF  
= 500mV  
CM  
R4A  
3.01k  
DC  
0mA TO 20mA  
0mA TO 20mA  
R1A  
100Ω  
R2A  
100Ω  
R3A  
1.3k  
1.3k  
1.8pF  
5.63k  
DAC  
C1  
C2  
C3  
R1B  
100Ω  
R2B  
100Ω  
R3B  
5.63k  
1.8pF  
R4B  
3.01k  
L1B  
L2B  
200Ω  
BBMI  
2.1V  
0.53V  
DC  
DC  
5518 F03  
GND  
GND  
C4B  
3.3nF  
Figure 3. LT5518 5th Order Filtered Baseband Interface with Common DAC (Only I-Channel is Shown)  
5518f  
9
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V
CC  
Some DACs use an output common mode voltage of 3.3V.  
In that case, the interface circuit drawn in Figure 4 may be  
used. The performance is very similar to the performance  
of the DAC interface drawn in Figure 3, since the source  
and load impedances of the lowpass ladder filter are both  
200Ω differential and the current drive is the same. There  
are some small differences:  
20pF  
LO  
INPUT  
Z
IN  
57Ω  
5518 F05  
Figure 5. Equivalent Circuit Schematic of the LO Input  
• Thebasebanddrivecapabilitycannotbeimprovedusing  
an extra supply voltage, since the compliance range of  
the DACs in Figure 4 is typically 3.3V – 0.5V to 3.3V +  
0.5V, so its range has already been fully used.  
significantly below 1.8GHz or above 2.4GHz, the quadra-  
ture accuracy will diminish, causing the image rejection  
to degrade. The LO pin input impedance is about 50Ω,  
and the recommended LO input power is 0dBm. For lower  
LO input power, the gain, OIP2, OIP3 and dynamic range  
• G and f  
are a little different, since R3A (and R3B)  
–3dB  
DC  
is 4.99k instead of 5.6k to accommodate the proper  
will degrade, especially below 5dBm and at T = 85°C.  
A
DC level shift.  
For high LO input power (e.g. 5dBm), the LO feedthrough  
will increase, without improvement in linearity or gain.  
HarmonicspresentontheLOsignalcandegradetheimage  
rejection,becausetheyintroduceasmallexcessphaseshift  
in the internal phase splitter. For the second (at 4GHz) and  
third harmonics (at 6GHz) at 20dBc level, the introduced  
signal at the image frequency is about 55dBc or lower,  
corresponding to an excess phase shift much less than 1  
degree. For the second and third harmonics at –10dBc,  
still the introduced signal at the image frequency is about  
46dBc. Higher harmonics than the third will have less  
impact. The LO return loss typically will be better than  
14dB over the 1.7GHz to 2.4GHz range. Table 1 shows  
the LO port input impedance vs frequency.  
LO Section  
The internal LO input amplifier performs single-ended to  
differential conversion of the LO input signal. Figure 5  
shows the equivalent circuit schematic of the LO input.  
The internal, differential LO signal is split into in-phase  
and quadrature (90° phase shifted) signals that drive LO  
buffer sections. These buffers drive the double balanced I  
andQmixers.ThephaserelationshipbetweentheLOinput  
and the internal in-phase LO and quadrature LO signals  
is fixed, and is independent of start-up conditions. The  
phase shifters are designed to deliver accurate quadrature  
signals for an LO frequency near 2GHz. For frequencies  
LT5518  
RF = 5.5dBm, MAX  
V
CC  
C
5V  
BALUN  
FROM  
Q
LOMI  
C4A  
3.3nF  
LOPI  
3.3V  
0mA TO  
20mA  
L1A  
L2A  
3.3V  
DC  
200  
BBPI  
2.1V  
V
REF  
= 500mV  
CM  
R4A  
3.01k  
DC  
R3A  
1.3k  
1.3k  
1.8pF  
4.99k  
DAC  
C1  
C2  
C3  
GND  
R3B  
4.99k  
1.8pF  
R4B  
3.01k  
L1B  
L2B  
200Ω  
BBMI  
0mA TO  
20mA  
2.1V  
3.3V  
DC  
DC  
5518 F04  
GND  
C4B  
3.3nF  
Figure 4. LT5518 5th Order Filtered Baseband Interface with 3.3VCM DAC (Only I-Channel is Shown).  
5518f  
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Table 1. LO Port Input Impedance vs Frequency for EN = High  
The RF output S with no LO power applied is given in  
22  
Frequency  
Input Impedance  
S
11  
Table 4.  
MHz  
Ω
Mag  
Angle  
95  
Table 4. RF Port Output Impedance vs Frequency for EN = High  
and No LO Power Applied  
1000  
1400  
1600  
1800  
2000  
2200  
2400  
2600  
44.5 + j18.2  
60.3 + j6.8  
62.8 – j0.6  
62.4 – j9.0  
56.7 – j15.6  
50.9 – j16.5  
46.6 – j15.2  
42.9 – j13.9  
0.197  
0.112  
0.113  
0.136  
0.157  
0.161  
0.159  
0.165  
30  
Frequency  
Input Impedance  
S
22  
2.4  
32  
58  
77  
94  
109  
MHz  
Ω
Mag  
Angle  
153  
119  
102  
103  
154  
160  
152  
144  
1000  
1400  
1600  
1800  
2000  
2200  
2400  
2600  
21.7 + j9.9  
32.3 + j19.5  
42.2 + j18.5  
46.8 + j9.6  
41.8 + j3.7  
36.1 + j4.3  
32.8 + j7.4  
31.2 + j10.5  
0.416  
0.312  
0.214  
0.104  
0.098  
0.170  
0.226  
0.264  
The input impedance of the LO port is different if the part  
is in shut-down mode. The LO input impedance for EN =  
Low is given in Table 2.  
Table 2. LO Port Input Impedance vs Frequency for EN = Low  
For EN = Low the S is given in Table 5.  
22  
Table 5. RF Port Output Impedance vs Frequency for EN = Low  
Frequency  
Input Impedance  
S
11  
MHz  
Ω
Mag  
Angle  
75  
15  
11  
33  
53  
70  
87  
104  
Frequency  
Input Impedance  
S
22  
1000  
1400  
1600  
1800  
2000  
2200  
2400  
2600  
42.1 + j43.7  
121 + j34.9  
134 – j31.6  
91.3 – j68.5  
56.4 – j66.3  
37.7 – j54.9  
27.9 – j43.6  
22.1 – j33.9  
0.439  
0.454  
0.483  
0.510  
0.532  
0.544  
0.550  
0.553  
MHz  
Ω
Mag  
Angle  
154  
1000  
1400  
1600  
1800  
2000  
2200  
2400  
2600  
20.9+j9.6  
28.5 + j20.2  
36.7 + j24.5  
48.7 + j23.1  
55.7 + j11.0  
48.9 + j0.6  
39.8 – j0.02  
34.2 + j3.2  
0.428  
0.365  
0.311  
0.229  
0.116  
0.013  
0.115  
0.193  
123  
103  
80.2  
56.7  
158.9  
–179  
167  
RF Section  
Afterup-conversion,theRFoutputsoftheIandQmixersare  
combined. An on-chip balun performs internal differential  
tosingle-endedoutputconversion,whiletransformingthe  
output signal impedance to 50Ω. Table 3 shows the RF  
port output impedance vs frequency.  
To improve S for lower frequencies, a shunt capacitor  
22  
can be added to the RF output. At higher frequencies, a  
shunt inductor can improve the S . Figure 6 shows the  
22  
equivalent circuit schematic of the RF output.  
V
CC  
Table 3. RF Port Output Impedance vs Frequency for EN = High  
and PLO = 0dBm  
20pF  
RF  
OUTPUT  
Frequency  
Input Impedance  
S
22  
MHz  
Ω
Mag  
Angle  
153  
21pF 3nH  
52.5Ω  
1000  
1400  
1600  
1800  
2000  
2200  
2400  
2600  
21.3 + j9.7  
29.8 + j20.3  
39.1 + j23.5  
50.8 + j18.4  
52.1 + j5.4  
43.2 – j0.1  
36.0 + j2.0  
32.1 + j5.6  
0.421  
0.348  
0.280  
0.180  
0.057  
0.073  
0.164  
0.228  
5518 F06  
121  
100  
Figure 6. Equivalent Circuit Schematic of the RF Output  
77.1  
65.5  
179  
171  
Note that an ESD diode is connected internally from  
the RF output to ground. For strong output RF signal  
levels (higher than 3dBm) this ESD diode can degrade  
the linearity performance if the 50Ω termination imped-  
159  
ance is connected directly to ground. To prevent this, a  
5518f  
11  
LT5518  
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J2  
APPLICATIO S I FOR ATIO  
coupling capacitor can be inserted in the RF output line.  
This is strongly recommended during a 1dB compression  
measurement.  
BBIM  
BBIP  
V
CC  
C2  
16  
BBMI GND BBPI  
EN  
15  
14  
13  
R1  
100nF  
V
CC  
GND  
100  
1
2
3
4
12  
11  
10  
9
V
EN  
J3  
CC  
RF  
OUT  
GND  
LO  
RF  
GND  
GND  
GND  
J4  
LO  
IN  
LT5518  
Enable Interface  
GND  
17  
Figure 7 shows a simplified schematic of the EN pin inter-  
face. The voltage necessary to turn on the LT5518 is 1.0V.  
To disable (shutdown) the chip, the Enable voltage must  
be below 0.5V. If the EN pin is not connected, the chip is  
disabled. This EN = Low condition is guaranteed by the  
75kΩ on-chip pull-down resistor. It is important that the  
BBMQ GND BBPQ  
V
CC  
5
6
7
8
C1  
100nF  
J5  
BBQM  
J6  
GND  
BBQP  
BOARD NUMBER: DC729A  
5518 F08  
voltage at the EN pin does not exceed V by more than  
Figure 8. Evaluation Board Circuit Schematic  
CC  
0.5V.Ifthisshouldoccur,thefullchipsupplycurrentcould  
be sourced through the EN pin ESD protection diodes.  
Damage to the chip may result.  
R3  
3.01k  
R4  
3.01k  
J1  
J2  
BBIM  
BBIP  
R5  
52.3Ω  
R6  
52.3Ω  
C1  
3.3nF  
C2  
R2  
5.62k  
V
CC  
E2  
V
CC  
3.3nF  
R1  
5.62k  
BOARD NUMBER: DC831A  
EN  
C3  
16  
BBMI GND BBPI  
EN  
15  
14  
13  
R7  
100nF  
V
CC  
GND  
75k  
25k  
100  
1
2
3
4
12  
11  
10  
9
V
EN  
J3  
CC  
E1  
RF  
OUT  
GND  
LO  
RF  
GND  
GND  
GND  
J4  
LO  
IN  
LT5518  
GND  
5518 F07  
17  
BBMQ GND BBPQ  
V
CC  
5
6
7
8
Figure 7. EN Pin Interface  
R10  
3.01k  
C4  
100nF  
J5  
R9  
5.62k  
BBQM  
R8  
5.62k  
R12  
52.3Ω  
Evaluation and Demo Boards  
C5  
3.3nF  
R11  
3.01k  
J6  
Figure 8 shows the schematic of the evaluation board that  
was used for the measurements summarized in the Elec-  
trical Characteristics tables and the Typical Performance  
Characteristic plots.  
BBQP  
GND  
E4  
GND  
E3  
R13  
52.3Ω  
C6  
3.3nF  
5518 F09  
Figure 9. Demo Board Circuit Schematic  
Figure 9 shows the demo board schematic. Resistors R3,  
R4, R10 and R11 may be replaced by shorting wires if a  
flat frequency response to DC is required. A good ground  
connection is required for the exposed pad of the LT5518  
package. If this is not done properly, the RF performance  
will degrade. The exposed pad also provides heat sink-  
ing for the part and minimizes the possibility of the chip  
overheating. R7 (optional) limits the Enable pin current in  
the event that the Enable pin is pulled high while the V  
CC  
inputs are low. In Figures 10, 11 and 12 the silk screen  
and the demo board PCB layouts are shown. If improved  
LOandImagesuppressionisrequired, anLOfeedthrough  
calibration and an Image suppression calibration can be  
performed.  
Figure 10. Component Side Silk Screen of Demo Board  
5518f  
12  
LT5518  
U
W U U  
APPLICATIO S I FOR ATIO  
Figure 11. Component Side Layout of Demo Board  
Figure 12. Bottom Side Layout of Demo Board  
5V  
100nF  
×2  
V
CC 8, 13  
LT5518  
14  
RF = 1.5GHz  
TO 2.4GHz  
I-DAC  
V-I  
I-CHANNEL  
16  
11  
PA  
0°  
1
EN  
90°  
BALUN  
LO FEEDTHROUGH CAL OUT  
IMAGE CAL OUT  
Q-CHANNEL  
V-I  
7
5
Q-DAC  
CAL  
BASEBAND  
GENERATOR  
3
VCO/SYNTHESIZER  
2, 4, 6, 9, 10, 12, 15, 17  
ADC  
5518 F13  
Figure 13. 1.5GHz to 2.4GHz Direct Conversion Transmitter  
Application with LO Feedthrough and Image Calibration Loop  
Application Measurements  
low, the ACPR will be limited by the noise performance of  
the part. In the middle, an optimum ACPR is obtained.  
TheLT5518isrecommendedforbase-stationapplications  
using various modulation formats. Figure 13 shows a  
typical application. The CAL box in Figure 13 allows for  
LO feedthrough and Image suppression calibration. Fig-  
ure 14 shows the ACPR performance for W-CDMA using  
one or four channel modulation. Figures 15, 16 and 17  
illustrate the 1, 2 and 4-channel W-CDMA measurement.  
To calculate ACPR, a correction is made for the spectrum  
analyzer noise floor.  
Because of the LT5518’s very high dynamic range, the test  
equipment can limit the accuracy of the ACPR measure-  
ment. Consult the factory for advice on ACPR measure-  
ment, if needed.  
TheACPRperformanceissensitivetotheamplitudematch  
of the BBIP and BBIM (or BBQP and BBQM) input voltage.  
This is because a difference in AC voltage amplitude will  
giverisetoadifferenceinamplitudebetweentheeven-order  
harmonic products generated in the internal V-I converter.  
If the output power is high, the ACPR will be limited by the  
linearity performance of the part. If the output power is  
As a result, they will not cancel out entirely. Therefore, it  
5518f  
13  
LT5518  
U
W U U  
APPLICATIO S I FOR ATIO  
is important to keep the amplitudes at the BBIP and BBIM  
inputs (or BBQP and BBQM) as equal as possible.  
and Image Rejection can also change as function of the  
baseband drive level, as is depicted in Figure 19. The RF  
output power, IM2 and IM3 vs two-tone baseband drive  
level are given in Figure 20.  
When the temperature is changed after calibration, the LO  
feedthrough and the Image Rejection performance will  
change.ThisisillustratedinFigure18.TheLOfeedthrough  
30  
–55  
–60  
–65  
–70  
–75  
–80  
–85  
–135  
–140  
–145  
–150  
–155  
–160  
–165  
DOWNLINK TEST  
4-CH ACPR  
MODEL 64 DPCH  
40  
50  
4-CH ALTCPR  
1-CH ACPR  
60  
70  
80  
UNCORRECTED  
SPECTRUM  
90  
1-CH ALTCPR  
CORRECTED  
SPECTRUM  
1-CH NOISE  
–100  
–110  
–120  
4-CH NOISE  
SYSTEM NOISE FLOOR  
DOWNLINK TEST MODEL 64 DPCH  
–34 –30 –26 –22 –18 –14 –10  
RF OUTPUT POWER PER CARRIER (dBm)  
2127.5 2132.5 2137.5  
2152.5  
2142.5 2147.5  
RF FREQUENCY (MHz)  
5518 F15  
5518 F14  
Figure 14. W-CDMA ACPR, ALTCPR and Noise vs  
RF Output Power at 2140MHz for 1 and 4 Channels  
Figure 15. 1-Channel W-CDMA Spectrum  
–30  
–40  
–40  
–40  
DOWNLINK TEST  
CALIBRATED WITH P = –30dBm  
RF  
UNCORRECTED  
SPECTRUM  
DOWNLINK  
TEST  
MODEL 64  
DPCH  
MODEL 64 DPCH  
–45  
–50  
–55  
–60  
–65  
–70  
–75  
–80  
–85  
–90  
–50  
–60  
IMAGE REJECTION  
–50  
–60  
–70  
–70  
–80  
CORRECTED  
SPECTRUM  
–80  
LO FEEDTHROUGH  
–90  
UNCORRECTED  
SPECTRUM  
–90  
–100  
–110  
–120  
–130  
CORRECTED  
SPECTRUM  
–100  
–110  
–120  
SYSTEM NOISE FLOOR  
SYSTEM NOISE FLOOR  
2125 2130 2135 2140 2145 2150 2155  
2115  
2125  
2135  
2145  
2155  
2165  
–40  
–20  
0
20  
40  
60  
80  
RF FREQUENCY (MHz)  
RF FREQUENCY (MHz)  
TEMPERATURE (°C)  
5518 F16  
5518 F17  
5518 F18  
Figure 16. 2-Channel W-CDMA  
Spectrum  
Figure 17. 4-Channel W-CDMA  
Spectrum  
Figure 18. LO Feedthrough and  
Image Rejection vs Temperature  
after Calibration at 25°C  
5518f  
14  
LT5518  
U
W U U  
APPLICATIO S I FOR ATIO  
20  
10  
0
P
RF  
RF  
10  
0
IM3  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–10  
20  
30  
40  
50  
60  
70  
80  
90  
LO FT  
IM2  
f
f
P
f
= 2MHz, 2.1MHz, 0°  
BBI  
BBQ  
LO  
= 2MHz, 2.1MHz, 90°  
= 0dBm  
= f + f  
f
f
P
f
= 2MHz, 0°  
= 2MHz, 90°  
= 0dBm  
RF BB LO  
BBI  
BBQ  
f
LO  
= 2.14GHz  
IR  
IM2 = POWER AT f + 4.1MHz  
LO  
LO  
= f + f  
IM3 = MAX POWER AT  
RF BB LO  
T
A
T
A
T
A
= 40°C  
= 85°C  
= 25°C  
T
T
T
= 40°C  
= 85°C  
= 25°C  
A
A
A
f
V
+ 1.9MHz or f + 2.2MHz  
f
= 2.14GHz  
LO  
LO  
CC  
LO  
= 5V  
V
= 5V  
CC  
EN = HIGH  
EN = HIGH  
0
1
2
3
4
5
0.1  
1
10  
5518 F20  
I AND Q BASEBAND VOLTAGE (V  
)
I AND Q BASEBAND VOLTAGE (V  
)
P-P, DIFF, EACH TONE  
P-P, DIFF  
5518 F19  
Figure 19. Image Rejection and LO Feedthrough  
vs Baseband Drive Voltage After Calibration at 25°C  
and VBBI = 0.2VP-P, DIFF  
Figure 20. RF Two-Tone Power, IM2 and  
IM3 at 2140MHz vs Baseband Voltage  
U
PACKAGE DESCRIPTIO  
UF Package  
16-Lead Plastic QFN (4mm × 4mm)  
(Reference LTC DWG # 05-08-1692)  
NOTE:  
0.72 0.05  
1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGC)  
2. DRAWING NOT TO SCALE  
3. ALL DIMENSIONS ARE IN MILLIMETERS  
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE  
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE  
5. EXPOSED PAD SHALL BE SOLDER PLATED  
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION  
ON THE TOP AND BOTTOM OF PACKAGE  
4.35 0.05  
2.90 0.05  
2.15 0.05  
(4 SIDES)  
PACKAGE OUTLINE  
0.30 0.05  
0.65 BSC  
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS  
BOTTOM VIEW—EXPOSED PAD  
PIN 1 NOTCH R = 0.20 TYP  
R = 0.115  
OR 0.35 × 45° CHAMFER  
0.75 0.05  
4.00 0.10  
(4 SIDES)  
TYP  
15  
16  
0.55 0.20  
PIN 1  
TOP MARK  
(NOTE 6)  
1
2
2.15 0.10  
(4-SIDES)  
(UF16) QFN 10-04  
0.200 REF  
0.30 0.05  
0.65 BSC  
0.00 – 0.05  
5518f  
InformationfurnishedbyLinearTechnologyCorporationisbelievedtobeaccurateandreliable.However,  
no responsibility is assumed for its use. Linear Technology Corporation makes no representation that  
the interconnection of its circuits as described herein will not infringe on existing patent rights.  
15  
LT5518  
RELATED PARTS  
PART NUMBER  
Infrastructure  
LT5511  
DESCRIPTION  
COMMENTS  
High Linearity Up-Converting Mixer  
RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer  
DC to 3GHz, 17dBm IIP3, Integrated LO Buffer  
LT5512  
DC-3GHz High Signal Level Down-Converting Mixer  
LT5514  
Ultralow Distortion, IF Amplifier/ADC Driver with  
Digitally Controlled Gain  
850MHz Bandwidth, 47dBm OIP3 at 100MHz,  
10.5dB to 33dB Gain Control Range  
LT5515  
LT5516  
LT5517  
LT5519  
1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator  
0.8GHz to 1.5GHz Direct Conversion Quadrature Demodulator  
40MHz to 900MHz Quadrature Demodulator  
20dBm IIP3, Integrated LO Quadrature Generator  
21.5dBm IIP3, Integrated LO Quadrature Generator  
21dBm IIP3, Integrated LO Quadrature Generator  
0.7GHz to 1.4GHz High Linearity Up-Converting Mixer  
17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50Ω  
Matching, Single-Ended LO and RF Ports Operation  
LT5520  
LT5521  
LT5522  
LT5524  
LT5525  
LT5526  
LT5528  
1.3GHz to 2.3GHz High Linearity Up-Converting Mixer  
10MHz to 3700MHz High Linearity Up-Converting Mixer  
600MHz to 2.7GHz High Signal Level Down-Converting Mixer  
15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with  
50Ω Matching, Single-Ended LO and RF Ports Operation  
24.2dBm IIP3 at 1.95GHz, NF = 12.5dB, 3.15V to 5.25V Supply,  
Single-Ended LO Port Operation  
4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω  
Single-Ended RF and LO Ports  
Low Power, Low Distortion ADC Driver with  
Digitally Programmable Gain  
450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control  
High Linearity, Low Power Downconverting Mixer  
High Linearity, Low Power Downconverting Mixer  
1.5GHz – 2.4GHz High Linearity Direct Quadrature Modulator  
Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz,  
I
= 28mA  
CC  
3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB,  
= 28mA  
I
CC  
4.5V to 5.25V Supply, 22dBm OIP3 at 2GHz, NFloor = 159dBm/Hz,  
50Ω Single-Ended BB, RF and LO Ports  
RF Power Detectors  
LT5504  
800MHz to 2.7GHz RF Measuring Receiver  
80dB Dynamic Range, Temperature Compensated,  
2.7V to 5.25V Supply  
LTC®5505  
LTC5507  
LTC5508  
LTC5509  
LTC5530  
LTC5531  
LTC5532  
LT5534  
RF Power Detectors with >40dB Dynamic Range  
100kHz to 1000MHz RF Power Detector  
300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply  
100kHz to 1GHz, Temperature Compensated, 2.7V to 6V Supply  
44dB Dynamic Range, Temperature Compensated, SC70 Package  
36dB Dynamic Range, Low Power Consumption, SC70 Package  
300MHz to 7GHz RF Power Detector  
300MHz to 3GHz RF Power Detector  
300MHz to 7GHz Precision RF Power Detector  
300MHz to 7GHz Precision RF Power Detector  
300MHz to 7GHz Precision RF Power Detector  
50MHz to 3GHz RF Power Detector with 60dB Dynamic Range  
Precision V  
Precision V  
Precision V  
Offset Control, Shutdown, Adjustable Gain  
Offset Control, Shutdown, Adjustable Offset  
Offset Control, Adjustable Gain and Offset  
OUT  
OUT  
OUT  
1dB Output Variation Overtemperature, 38ns Response Time  
Low Voltage RF Building Block  
LT5546 500MHz Quadrature Demodulator with VGA  
and 17MHz Baseband Bandwidth  
Wide Bandwidth ADCs  
17MHz Baseband Bandwidth, 40MHz to 500MHz IF,  
1.8V to 5.25V Supply, 7dB to 56dB Linear Power Gain  
LT1749  
LT1750  
12-Bit, 80Msps  
500MHz BW S/H, 71.8dB SNR  
500MHz BW S/H, 75.5dB SNR  
14-Bit, 80Msps  
5518f  
LT/TP 0205 1K • PRINTED IN USA  
LinearTechnology Corporation  
1630 McCarthy Blvd., Milpitas, CA 95035-7417  
16  
(408) 432-1900 FAX: (408) 434-0507 www.linear.com  
© LINEAR TECHNOLOGY CORPORATION 2005  

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