FEATURES
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LT5558
600MHz to 1100MHz
High Linearity Direct
Quadrature Modulator
DESCRIPTION
The LT
®
5558 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
GSM, EDGE, CDMA, CDMA2000, and other systems. It
may also be configured as an image reject upconverting
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 which produce the LO drive for the mixers.
The supply voltage range is 4.5V to 5.25V.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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Direct Conversion from Baseband to RF
High OIP3: + 22.4dBm at 900MHz
Low Output Noise Floor at 20MHz Offset:
No RF: –158dBm/Hz
P
OUT
= 4dBm: –152.7dBm/Hz
Low Carrier Leakage: –43.7dBm at 900MHz
High Image Rejection: –49dBc at 900MHz
3 Channel CDMA2000 ACPR: –70.4dBc at 900MHz
Integrated LO Buffer and LO Quadrature Phase
Generator
50Ω AC-Coupled Single-ended LO and RF Ports
High Impedance Interface to Baseband Inputs
with 2.1V Common Mode Voltage
16-Lead QFN 4mm
×
4mm Package
APPLICATIONS
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RFID Single-Sideband Transmitters
Infrastructure T
X
for Cellular and ISM Bands
Image Reject Up-Converters for Cellular Bands
Low-Noise Variable Phase-Shifter for 600MHz to
1100MHz Local Oscillator Signals
Microwave Links
TYPICAL APPLICATION
600MHz to 1100MHz Direct Conversion Transmitter Application
V
CC
8, 13
14
IDAC
16
V-1
I-CH
1
EN
90°
7
QDAC
5
Q-CH
V-1
BALUN
O°
11
LT5558
ACPR, ALTCPR (dBc)
CDMA2000 ACPR, AltCPR and Noise vs
RF Output Power at 900MHz for 1 and 3 Carriers
–40
DOWNLINK TEST
MODEL 64 DPCH
3-CH ACPR
3-CH ALTCPR
–60
1-CH ACPR
–70
1-CH NOISE
–80
1-CH ALTCPR
3-CH NOISE
–150
–140
–130
–110
NOISE FLOOR AT 30MHz OFFSET (dBm/Hz)
5V
2 x 100nF
∫
RF = 600MHz TO
1100MHz
PA
–50
–120
∫
BASEBAND
GENERATOR
2, 4, 6, 9, 10,
12, 15, 17
3
VCO/SYNTHESIZER
5558 TA01
–90
–30
–20
–15
–10
–5
0
–25
RF OUTPUT POWER PER CARRIER (dBm)
5558 TA01b
–160
5558fa
1
LT5558
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
TOP VIEW
BBMI
BBPI
GND
V
CC
BBMQ
BBPQ
Supply Voltage ........................................................5.5V
Common-Mode Level of BBPI, BBMI and
BBPQ, BBMQ .......................................................2.5V
Voltage on any Pin
Not to Exceed....................–500mV to (V
CC
+ 500mV)
Operating Ambient Temperature
(Note 2) ............................................... –40°C to 85°C
Storage Temperature Range................... –65°C to 125°C
ORDER PART NUMBER
LT5558EUF
12 GND
11 RF
10 GND
9
GND
16 15 14 13
EN 1
GND 2
LO 3
GND 4
5
6
GND
7
8
V
CC
UF PART MARKING
5558
UF PACKAGE
16-LEAD (4mm
×
4mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 37°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE
SOLDERED TO PCB
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
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
RF Frequency Range
RF Output Return Loss
RF Output Return Loss
RF Output Noise Floor
PARAMETER
V
CC
= 5V, EN = High, T
A
= 25°C, f
LO
= 900MHz, f
RF
= 902MHz,
P
LO
= 0dBm. BBPI, BBMI, BBPQ, BBMQ CM input voltage = 2.1V
DC
, baseband input frequency = 2MHz, I and Q 90° shifted
(upper sideband selection). P
RF(OUT)
= –10dBm, unless otherwise noted. (Note 3)
CONDITIONS
–3 dB Bandwidth
–1 dB Bandwidth
EN = High (Note 6)
EN = Low (Note 6)
No Input Signal (Note 8)
P
RF
= 4dBm (Note 9)
P
RF
= 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)
P
RF
= 2dBm
MIN
TYP
600 to 1100
680 to 960
–15.8
–13.3
–158
–152.7
–152.3
9.7
–5.1
–1.1
–26.5
7.8
65
22.4
–49
–43.7
–60
0.6
600 to 1100
–10
0
5
MAX
UNITS
MHz
MHz
dB
dB
dBm/Hz
dBm/Hz
dBm/Hz
dB
dB
dBm
dB
dBm
dBm
dBm
dBc
dBm
dBm
%
MHz
dBm
5558fa
G
P
G
V
P
OUT
G
3LO vs LO
OP1dB
OIP2
OIP3
IR
LOFT
EVM
LO Input (LO)
f
LO
P
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)
GSM Error Vector Magnitude
LO Frequency Range
LO Input Power
2
LT5558
ELECTRICAL CHARACTERISTICS
SYMBOL
S
11, ON
S
11, OFF
NF
LO
G
LO
IIP3
LO
BW
BB
V
CMBB
R
IN, DIFF
R
IN, CM
I
CM, COMP
P
LO-BB
IP1dB
ΔG
I/Q
Δϕ
I/Q
V
CC
I
CC(ON)
I
CC(OFF)
t
ON
t
OFF
Enable
Shutdown
PARAMETER
LO Input Return Loss
LO Input Return Loss
LO Input Referred Noise Figure
LO to RF Small-Signal Gain
LO Input 3rd Order Intercept
Baseband Bandwidth
DC Common-mode Voltage
Differential Input Resistance
Common Mode Input Resistance
Common Mode Compliance Current range
Carrier Feedthrough on BB
Input 1dB compression point
I/Q Absolute Gain Imbalance
I/Q Absolute Phase Imbalance
Supply Voltage
Supply Current
Supply Current, Sleep mode
Turn-On Time
Turn-Off Time
Input High Voltage
Input High Current
Input Low Voltage
EN = High
EN = 0V
EN = Low to High (Note 11)
EN = High to Low (Note 12)
EN = High
EN = 5V
EN = Low
1
230
0.5
4.5
V
CC
= 5V, EN = High, T
A
= 25°C, f
LO
= 900MHz, f
RF
= 902MHz,
P
LO
= 0dBm. BBPI, BBMI, BBPQ, BBMQ CM input voltage = 2.1V
DC
, baseband input frequency = 2MHz, I and Q 90° shifted
(upper sideband selection). P
RF(OUT)
= –10dBm, unless otherwise noted. (Note 3)
CONDITIONS
EN = High (Note 6)
EN = Low (Note 6)
(Note 5) at 900MHz
(Note 5) at 900MHz
(Note 5) at 900MHz
–3dB Bandwidth
(Note 4)
Between BBPI and BBMI (or BBPQ and BBMQ)
(Note 20)
(Notes 18, 20)
P
OUT
= 0 (Note 4)
Differential Peak-to-Peak (Notes 7, 19)
MIN
TYP
–10.6
–2.5
14.6
16.4
–3.3
400
2.1
3
100
–820 to 440
–46
3.4
0.05
0.2
5
108
0.1
0.3
1.1
5.25
135
50
MAX
UNITS
dB
dB
dB
dB
dBm
MHz
V
kΩ
Ω
μA
dBm
V
P-P,DIFF
dB
Deg
V
mA
μA
μs
μs
V
μA
V
Baseband Inputs (BBPI, BBMI, BBPQ, BBMQ)
Power Supply (V
CC
)
Enable (EN), Low = Off, High = On
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:
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 7.
Note 4:
At 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 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 = 900MHz.
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 19:
The input voltage corresponding to the output P1dB.
Note 20:
BBPI and BBMI shorted together (or BBPQ and BBMQ shorted
together).
5558fa
3
LT5558
TYPICAL PERFORMANCE CHARACTERISTICS
V
CC
= 5V, EN = High, T
A
= 25°C, f
LO
= 900MHz,
f
RF
= 902MHz, P
LO
= 0dBm. BBPI, BBMI, BBPQ, BBMQ CM input voltage = 2.1V
DC
, baseband input frequency = 2MHz, I and Q 90°
shifted, without image or LO feedthrough nulling. f
RF
= f
BB
+ f
LO
(upper side-band selection). P
RF(OUT)
= –10dBm (–10dBm/tone for
2-tone measurements), unless otherwise noted. (Note 3)
RF Output Power vs LO Frequency
at 1V
P-P
Differential
Voltage Gain vs LO Frequency
Supply Current vs Supply Voltage
Baseband Drive
130
2
0
SUPPLY CURRENT (mA)
120
85°C
110
25°C
100
–40°C
RF OUTPUT POWER (dBm)
VOLTAGE GAIN (dB)
–2
–4
–6
–8
–10
90
4.5
4.75
5
SUPPLY VOLTAGE (V)
5.25
5558 G01
–2
–4
–6
–8
–10
–12
–14
–16
550
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
650 750
850
950 1050 1150 1250
5558 G03
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
650 750
950 1050 1150 1250
LO FREQUENCY (MHz)
5558 G02
–12
550
850
LO FREQUENCY (MHz)
Output IP3 vs LO Frequency
26
24
22
OIP3 (dBm)
20
18
16
14
12
550
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
650 750
950 1050 1150 1250
LO FREQUENCY (MHz)
5558 G04
Output IP2 vs LO Frequency
75
f
IM2
= f
BB
,
1
+ f
BB
,
2
+ f
LO
f
BB
,
1
= 2MHz
70 f
BB
,
2
= 2.1MHz
10
8
6
4
2
0
Output 1dB Compression vs LO
Frequency
f
BB
, 1 = 2MHz
f
BB
, 2 = 2.1MHz
60
55
50
45
550
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
650 750
950 1050 1150 1250
LO FREQUENCY (MHz)
5558 G05
OP1dB (dBm)
65
OIP2 (dBm)
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
650 750
850
950 1050 1150 1250
5558 G06
850
850
–2
550
LO FREQUENCY (MHz)
LO Feedthrough to RF Output vs
LO Frequency
–40
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
–40
2 • LO Leakage to RF Output vs
2 • LO Frequency
–45
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
3 • LO Leakage to RF Output vs
3 • LO Frequency
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
LO FEEDTHROUGH (dBm)
2 • LO LEAKAGE (dBm)
3 • LO LEAKAGE (dBm)
–42
–45
–50
–55
–44
–50
–60
–46
–55
–65
–48
550
650 750
950 1050 1150 1250
LO FREQUENCY (MHz)
5558 G07
850
–60
1.1
1.3
2.3
2 • LO FREQUENCY (GHz)
1.5
1.7
1.9
2.1
2.5
5558 G08
–70
1.65 1.95 2.25 2.55 2.85 3.15 3.5 3.75
3 • LO FREQUENCY (GHz)
5558 G09
5558fa
4
LT5558
f
RF
= 902MHz, P
LO
= 0dBm. BBPI, BBMI, BBPQ, BBMQ CM input voltage = 2.1V
DC
, baseband input frequency = 2MHz, I and Q 90°
shifted, without image or LO feedthrough nulling. f
RF
= f
BB
+ f
LO
(upper side-band selection). P
RF(OUT)
= –10dBm (–10dBm/tone for
2-tone measurements), unless otherwise noted. (Note 3)
Noise Floor vs RF Frequency
–157
f
LO
= 900MHz (FIXED)
NO BASEBAND SIGNAL
IMAGE REJECTION (dBc)
–30
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
S
11
(dB)
TYPICAL PERFORMANCE CHARACTERISTICS
V
CC
= 5V, EN = High, T
A
= 25°C, f
LO
= 900MHz,
LO and RF Port Return Loss
vs RF Frequency
0
Image Rejection vs LO Frequency
LO PORT, EN = LOW
–10
LO PORT, EN = HIGH, P
LO
= 0dBm
–158
NOISE FLOOR (dBm/Hz)
–35
–159
–40
–20
RF PORT, EN = LOW
RF PORT, EN = HIGH,
P
LO
= 0dBm
–160
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
650 750
950 1050 1150 1250
RF FREQUENCY (MHz)
5558 G24
–45
–161
–30
–50
LO PORT, EN = HIGH,
P
LO
= –10dBm
RF PORT, EN = HIGH, NO LO
650 750
850
950 1050 1150 1250
5558 G25
–162
550
850
–55
550
650 750
850
950 1050 1150 1250
5558 G10
–40
550
LO FREQUENCY (MHz)
FREQUENCY (MHz)
Absolute I/Q Gain Imbalance vs
LO Frequency
0.2
ABSOLUTE I/Q PHASE IMBALANCE (DEG)
ABSOLUTE I/Q GAIN IMBALANCE (dB)
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
0.1
4
Absolute I/Q Phase Imbalance vs
LO Frequency
–2
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
–4
–6
VOLTAGE GAIN (dB)
–8
–10
–12
–14
–16
–18
0
550
650 750
950 1050 1150 1250
LO FREQUENCY (MHz)
5558 G12
Voltage Gain vs LO Power
3
2
1
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
–16 –12
–8
–4
0
4
8
5558 G13
0
550
650 750
950 1050 1150 1250
LO FREQUENCY (MHz)
5558 G11
850
850
–20
–20
LO INPUT POWER (dBm)
Output IP3 vs LO Power
24
22
LO FEEDTHROUGH (dBm)
–42
20
OIP3 (dBm)
18
16
14
12
10
–20
f
BB, 1
= 2MHz
f
BB, 2
= 2.1MHz
–16 –12
–8
–4
0
4
8
5558 G14
LO Feedthrough vs LO Power
–40
–35
Image Rejection vs LO Power
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
–44
IMAGE REJECTION (dBc)
–40
–45
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
–16 –12
–8
–4
0
4
8
5558 G16
–46
5V, –40°C
5V, 25°C
5V, 85°C
4.5V, 25°C
5.5V, 25°C
–16 –12
–8
–4
0
4
8
5558 G15
–50
–48
–50
–20
–55
–20
LO INPUT POWER (dBm)
LO INPUT POWER (dBm)
LO INPUT POWER (dBm)
5558fa
5