LT5518
1.5GHz–2.4GHz
High Linearity Direct
Quadrature Modulator
FEATURES
■
■
■
■
DESCRIPTIO
■
■
■
■
■
■
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
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
2.4GHz Local Oscillator Signals
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
using differential baseband I and Q signals. It supports PHS,
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
1.5GHz to 2.4GHz Direct Conversion Transmitter Application
with LO Feedthrough and Image Calibration Loop
V
CC
8, 13
14
I-DAC
16
V-I
I-CHANNEL
EN
1
Q-CHANNEL
V-I
CAL
BASEBAND
GENERATOR
0°
90°
7
Q-DAC
5
BALUN
11
LT5518
5V
100nF
×2
RF = 1.5GHz
TO 2.4GHz
PA
LO FEEDTHROUGH
CAL OUT
IMAGE CAL OUT
W-CDMA ACPR, AltCPR and Noise vs RF Output
Power at 2140MHz for 1 and 4 Channels
–55
4-CH ACPR
–60
ACPR, ALTCPR (dBc)
–65
1-CH ACPR
–70
–75
–80
1-CH ALTCPR
4-CH NOISE
–150
–155
1-CH NOISE
–160
–165
4-CH ALTCPR
–140
–145
–135
NOISE FLOOR AT 30MHz OFFSET (dBm/Hz)
2, 4, 6, 9, 10, 12, 15, 17
3
VCO/SYNTHESIZER
ADC
5518 TA01a
DOWNLINK TEST MODEL 64 DPCH
–85
–34 –30 –26 –22 –18
–14 –10
RF OUTPUT POWER PER CARRIER (dBm)
5518 TA01b
U
5518f
U
U
1
LT5518
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
BBMI
BBPI
GND
V
CC
BBMQ
BBPQ
Supply Voltage .........................................................5.5V
Common Mode Level of BBPI, BBMI and
BBPQ, BBMQ .......................................................2.5V
Operating Ambient Temperature
(Note 2) .............................................. –40°C to 85°C
Storage Temperature Range.................. –65°C to 125°C
Voltage on Any Pin
Not to Exceed...................... –500mV to V
CC
+ 500mV
ORDER PART
NUMBER
12 GND
16 15 14 13
EN 1
GND 2
LO 3
GND 4
5
6
GND
7
8
V
CC
17
LT5518EUF
11 RF
10 GND
9
GND
UF PART
MARKING
5518
T
JMAX
= 125°C,
θ
JA
= 37°C/W
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
SYMBOL
RF Output (RF)
f
RF
S
22, ON
S
22, OFF
NFloor
PARAMETER
RF Frequency Range
RF Frequency Range
RF Output Return Loss
RF Output Return Loss
RF Output Noise Floor
V
CC
= 5V, EN = High, T
A
= 25°C, f
LO
= 2GHz, f
RF
= 2.002GHz, P
LO
= 0dBm.
BBPI, BBMI, BBPQ, BBMQ inputs 2.06V
DC
, Baseband Input Frequency = 2MHz, I and Q 90° shifted (upper sideband selection).
P
RF, OUT
= –10dBm, unless otherwise noted. (Note 3)
CONDITIONS
–3dB Bandwidth
–1dB Bandwidth
EN = High (Note 6)
EN = Low (Note 6)
No Input Signal (Note 8)
P
OUT
= 4dBm (Note 9)
P
OUT
= 4dBm (Note 10)
P
OUT
/P
IN
, I&Q
20 • log(V
OUT, 50Ω
/V
IN, DIFF, I or Q
)
1V
P-P, DIFF
CW Signal, I and Q
(Note 17)
(Note 7)
(Notes 13, 14)
(Notes 13, 15)
(Note 16)
EN = High, P
LO
= 0dBm (Note 16)
EN = Low, P
LO
= 0dBm (Note 16)
MIN
TYP
1.5 to 2.4
1.7 to 2.2
–14
–12
–158.2
–152.5
–151.1
10.6
–4
0
–28
8.5
49
22.8
–40
–49
–58
1.5 to 2.4
0
–18
–5
14
23.8
–9
MAX
UNITS
GHz
GHz
dB
dB
dBm/Hz
dBm/Hz
dBm/Hz
dB
dB
dBm
dB
dBm
dBm
dBm
dBc
dBm
dBm
GHz
dBm
dB
dB
dB
dB
dBm
5518f
G
P
G
V
P
OUT
G
3LO vs LO
OP1dB
OIP2
OIP3
IR
LOFT
LO Input (LO)
f
LO
P
LO
S
11, ON
S
11, OFF
NF
LO
G
LO
IIP3
LO
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
Carrier Leakage
(LO Feedthrough)
LO Frequency Range
LO Input Power
LO Input Return Loss
LO Input Return Loss
LO Input Referred Noise Figure
LO to RF Small Signal Gain
LO Input Linearity
–10
EN = High (Note 6)
EN = Low (Note 6)
(Note 5) at 2GHz
(Note 5) at 2GHz
(Note 5) at 2GHz
5
2
U
W
U
U
W W
W
LT5518
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
Baseband Inputs (BBPI, BBMI, BBPQ, BBMQ)
Baseband Bandwidth
BW
BB
V
CMBB
DC Common Mode Voltage
R
IN, DIFF
Differential Input Resistance
R
IN, CM
Common Mode Input Resistance
I
CM, COMP
Common Mode Compliance Current Range
P
LO2BB
Carrier Feedthrough on BB
IP1dB
Input 1dB Compression Point
ΔG
I/Q
I/Q Absolute Gain Imbalance
Δφ
I/Q
I/Q Absolute Phase Imbalance
Power Supply (V
CC
)
V
CC
Supply Voltage
I
CC, ON
Supply Current
I
CC, OFF
Supply Current, Sleep Mode
t
ON
Turn-On Time
t
OFF
Turn-Off Time
Enable (EN), Low = Off, High = On
Enable
Input High Voltage
Input High Current
Sleep
Input Low Voltage
V
CC
= 5V, EN = High, T
A
= 25°C, f
LO
= 2GHz, f
RF
= 2.002GHz, P
LO
= 0dBm.
BBPI, BBMI, BBPQ, BBMQ inputs 2.06V
DC
, Baseband Input Frequency = 2MHz, I and Q 90° shifted (upper sideband selection).
P
RF, OUT
= –10dBm, unless otherwise noted. (Note 3)
CONDITIONS
–3dB Bandwidth
(Note 4)
Between BBPI and BBMI (or BBPQ and BBMQ)
BBPX and BBMX Shorted Together
BBPX and BBMX Shorted Together (Note 18)
P
OUT
= 0 (Note 4)
Differential Peak-to-Peak (Note 7)
MIN
TYP
400
2.06
2.9
105
–730 to 480
–40
2.7
0.06
1
4.5
EN = High
EN = 0V
EN = Low to High (Note 11)
EN = High to Low (Note 12)
EN = High
EN = 5V
EN = Low
1.0
240
0.5
5
128
0.05
0.2
1.3
5.25
145
50
MAX
UNITS
MHz
V
kΩ
Ω
µA
dBm
V
P-P, DIFF
dB
deg
V
mA
µA
µs
µs
V
µA
V
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
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 5:
V(BBPI) – V(BBMI) = 1V
DC
, V(BBPQ) – V(BBMQ) = 1V
DC
.
Note 6:
Maximum value within –1dB bandwidth.
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.
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 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 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.
5518f
3
LT5518
V
CC
= 5V, EN = High, T
A
= 25°C, f
LO
= 2.14GHz,
P
LO
= 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 2.06V
DC
, Baseband Input Frequency f
BB
= 2MHz, I and Q 90° shifted without image or
LO feedthrough nulling. f
RF
= f
BB
+ f
LO
(upper sideband selection). P
RF, OUT
= –10dBm (–10dBm/tone for 2-tone measurements), unless
otherwise noted. (Note 3)
Voltage Gain and Output 1dB
RF Output Power vs LO Frequency
Compression vs LO Frequency
at 1V
P-P
Differential Baseband Drive
and Temperature
Supply Current vs Supply Voltage
140
T
A
= 85°C
VOLTAGE GAIN (dB), OP1dB (dBm)
10 OP1dB
5
0
GAIN
–5
–10
–15
1.3
130
T
A
= 25°C
RF OUTPUT POWER (dBm)
5
15
4.5V
5.5V
5V
TYPICAL PERFOR A CE CHARACTERISTICS
SUPPLY CURRENT (mA)
120
T
A
= –40°C
110
100
4.5
5.0
SUPPLY VOLTAGE (V)
Voltage Gain and Output 1dB
Compression vs LO Frequency
and Supply Voltage
15
VOLTAGE GAIN (dB), OP1dB (dBm)
10
5
OIP3 (dBm)
0
–5
–10
–15
1.3
GAIN
4.5V
5.5V
5V
OP1dB
18
16
–154
–156
–158
–160
–162
OIP3 (dBm)
1.5
2.3
1.7 1.9 2.1
LO FREQUENCY (GHz)
LO Feedthrough to RF Output vs
LO Frequency
– 40
– 25
– 30
– 45
P(2 • LO) (dBm)
– 35
– 40
– 45
– 50
LO FT (dBm)
P(3 • LO) (dBm)
– 50
– 55
– 60
5V, T
A
= – 40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
1.3
1.5
2.3
1.7 1.9 2.1
LO FREQUENCY (GHz)
2.5
2.7
4
U W
5518 G01
0
–5
–10
5.5
–15
1.3
5V, T
A
= –40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
1.5
1.7
2.3
LO FREQUENCY (GHz)
1.9
2.1
2.5
2.7
1.5
1.7
2.3
LO FREQUENCY (GHz)
1.9
2.1
2.5
2.7
5518 G02
5518 G03
26
24
22
20
Output IP3 and Noise Floor vs LO
Frequency and Temperature
OIP3
–146
T
A
= – 40°C
T
A
= 85°C –148
T
A
= 25°C
–150
NOISE FLOOR (dBm/Hz)
–152
26
24
22
20
18
16
Output IP3 and Noise Floor vs LO
Frequency and Supply Voltage
OIP3
4.5V
5.5V
5V
f
BB, 1
= 2MHz
f
BB, 2
= 2.1MHz
–146
–148
–150
NOISE FLOOR (dBm/Hz)
–152
–154
–156
–158
–160
–162
f
BB, 1
= 2MHz
f
BB, 2
= 2.1MHz
14 NOISE FLOOR
12
10
8
14 NOISE FLOOR
12
10
8
6
1.3
1.5
2.5
2.7
6
1.3
1.5
NO BASEBAND SIGNAL
–164
f
LO
= 2.14GHz (FIXED) FOR NOISE
–166
2.5
2.7
2.3
1.7 1.9 2.1
LO/NOISE FREQUENCY (GHz)
5518 G05
NO BASEBAND SIGNAL
–164
f
LO
= 2.14GHz (FIXED) FOR NOISE
–166
2.5 2.7
2.3
1.7 1.9 2.1
LO/NOISE FREQUENCY (GHz)
5518 G06
5518 G04
2 • LO Leakage to RF Output vs
2 • LO Frequency
5V, T
A
= – 40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
–30
–35
–40
–45
–50
–55
–60
–65
3.0
5.0
4.6
3.4 3.8 4.2
2 • LO FREQUENCY (GHz)
5.4
3 • LO Leakage to RF Output vs
3 • LO Frequency
– 55
2.6
–70
3.9
5V, T
A
= – 40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
4.5
5.1
5.7
6.3
6.9
7.5
8.1
3 • LO FREQUENCY (GHz)
5518 G09
5518 G07
5518 G08
5518f
LT5518
V
CC
= 5V, EN = High, T
A
= 25°C, f
LO
= 2.14GHz,
P
LO
= 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 2.06V
DC
, Baseband Input Frequency f
BB
= 2MHz, I and Q 90° shifted without image
or LO feedthrough nulling. f
RF
= f
BB
+ f
LO
(upper sideband selection). P
RF, OUT
= –10dBm (–10dBm/tone for 2-tone measurements),
unless otherwise noted. (Note 3)
Image Rejection vs LO Frequency
–25
–30
IMAGE REJECTION (dBc)
–35
–40
–45
–50
–55
1.3
5V, T
A
= – 40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
1.5
1.7
2.3
LO FREQUENCY (GHz)
1.9
2.1
2.5
2.7
ABSOLUTE I/Q GAIN IMBALANCE (dB)
02
TYPICAL PERFOR A CE CHARACTERISTICS
ABSOLUTE I/Q PHASE IMBALANCE (DEG)
Voltage Gain vs LO Power
–2
–4
–6
VOLTAGE GAIN (dB)
OIP3 (dBm)
–8
–10
–12
–14
–16
5V, T
A
= –40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
8
5518 G13
16
14
12
10
8
6
5V, T
A
= – 40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
8
5518 G14
HD2, HD3 (dBc)
–18
0
4
–20 –16 –12 – 8 – 4
LO INPUT POWER (dBm)
RF CW Output Power, HD2 and
HD3 vs Baseband Voltage and
Supply Voltage
–10
–20
HD2, HD3 (dBc)
–30
–40
–50
HD2
10
0
HD3
4.5V
5.5V
5V
– 10
– 20
– 30
– 25
– 30
LO FT (dBm), IR (dBc)
– 35
– 40
– 45
RF
LO FT (dBm), IR (dBc)
HD2 = MAX POWER AT
f
LO
+ 2 • f
BB
OR f
LO
– 2 • f
BB
– 40
–60
HD3 = MAX POWER AT
f
LO
+ 3 • f
BB
OR f
LO
– 3 • f
BB
–70
– 50
5
0
2
3
4
1
I AND Q BASEBAND VOLTAGE (V
P-P, DIFF
)
5518 G16
U W
5518 G10
Absolute I/Q Gain Imbalance
vs LO Frequency
5V, T
A
= – 40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
5
Absolute I/Q Phase Imbalance
vs LO Frequency
5V, T
A
= – 40°C
5V, T
A
= 25°C
5V, T
A
= 85°C
4.5V, T
A
= 25°C
5.5V, T
A
= 25°C
4
3
0.1
2
1
0
1.3
1.5
1.7
2.3
LO FREQUENCY (GHz)
1.9
2.1
2.5
2.7
0
1.3
1.5
1.7
2.3
LO FREQUENCY (GHz)
1.9
2.1
2.5
2.7
5518 G11
5518 G12
Output IP3 vs LO Power
24
22
20
18
– 20
– 30
– 40
– 10
RF CW Output Power, HD2 and HD3 vs
Baseband Voltage and Temperature
10
0
HD3
T
A
= – 40°C – 10
T
A
= 85°C
T
A
= 25°C
– 20
HD2
– 50
– 60
– 30
HD2 = MAX POWER AT
f
LO
+ 2 • f
BB
OR f
LO
– 2 • f
BB
– 40
HD3 = MAX POWER AT
f
LO
+ 3 • f
BB
OR f
LO
– 3 • f
BB
– 70
– 50
0
2
3
4
5
1
I AND Q BASEBAND VOLTAGE (V
P-P, DIFF
)
5518 G15
RF CW OUTPUT POWER (dBm)
RF
4
0
–20 –16 –12 – 8 – 4
4
LO INPUT POWER (dBm)
LO Feedthrough to RF Output and
Image Rejection vs Baseband
Voltage and Temperature
T
A
= – 40°C
T
A
= 85°C
T
A
= 25°C
– 25
LO FT
– 30
– 35
– 40
– 45
LO Feedthrough to RF Output and
Image Rejection vs Baseband
Voltage and Supply Voltage
4.5V
5.5V
5V
LO FT
RF CW OUTPUT POWER (dBm)
IR
– 50
– 55
– 50
– 55
IR
0
5
2
3
4
1
I AND Q BASEBAND VOLTAGE (V
P-P, DIFF
)
5518 G17
0
5
2
3
4
1
I AND Q BASEBAND VOLTAGE (V
P-P, DIFF
)
5518 G18
5518f
5
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