LINER LT5518

LT5518
1.5GHz–2.4GHz
High Linearity Direct
Quadrature Modulator
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DESCRIPTIO
FEATURES
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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.
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
POUT = 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
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APPLICATIO S
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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
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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TYPICAL APPLICATIO
1.5GHz to 2.4GHz Direct Conversion Transmitter Application
with LO Feedthrough and Image Calibration Loop
I-DAC
16
V-I
I-CHANNEL
EN
90°
7
Q-DAC
11
5
PA
0°
1
Q-CHANNEL
LO FEEDTHROUGH
CAL OUT
BALUN
V-I
IMAGE CAL OUT
–135
–55
4-CH ACPR
–60
ACPR, ALTCPR (dBc)
LT5518
–145
–65
1-CH ACPR
–150
–70
–75
1-CH ALTCPR
CAL
BASEBAND
GENERATOR
–80
2, 4, 6, 9, 10, 12, 15, 17
3
VCO/SYNTHESIZER
–140
4-CH ALTCPR
–155
1-CH NOISE
–160
4-CH NOISE
DOWNLINK TEST MODEL 64 DPCH
–85
–34 –30 –26 –22 –18
–14 –10
RF OUTPUT POWER PER CARRIER (dBm)
ADC
5518 TA01a
NOISE FLOOR AT 30MHz OFFSET (dBm/Hz)
5V
100nF
×2
RF = 1.5GHz
TO 2.4GHz
VCC 8, 13
14
W-CDMA ACPR, AltCPR and Noise vs RF Output
Power at 2140MHz for 1 and 4 Channels
–165
5518 TA01b
5518f
1
LT5518
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W W
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ABSOLUTE
AXI U RATI GS
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W
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PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
NUMBER
VCC
BBPI
BBMI
GND
TOP VIEW
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 VCC + 500mV
16 15 14 13
EN 1
LT5518EUF
12 GND
GND 2
11 RF
17
LO 3
10 GND
GND 4
6
7
8
BBMQ
GND
BBPQ
VCC
9
5
UF PART
MARKING
GND
5518
TJMAX = 125°C, θJA = 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
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
RF Output (RF)
fRF
S22, ON
S22, OFF
NFloor
GP
GV
POUT
G3LO vs LO
OP1dB
OIP2
OIP3
IR
LOFT
LO Input (LO)
fLO
PLO
S11, ON
S11, OFF
NFLO
GLO
IIP3LO
PARAMETER
CONDITIONS
RF Frequency Range
RF Frequency Range
–3dB Bandwidth
–1dB Bandwidth
RF Output Return Loss
RF Output Return Loss
RF Output Noise Floor
EN = High (Note 6)
EN = Low (Note 6)
No Input Signal (Note 8)
POUT = 4dBm (Note 9)
POUT = 4dBm (Note 10)
POUT/PIN, I&Q
20 • log(VOUT, 50Ω/VIN, DIFF, I or Q)
1VP-P, DIFF CW Signal, I and Q
(Note 17)
(Note 7)
(Notes 13, 14)
(Notes 13, 15)
(Note 16)
EN = High, PLO = 0dBm (Note 16)
EN = Low, PLO = 0dBm (Note 16)
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
MIN
MAX
1.5 to 2.4
1.7 to 2.2
1.5 to 2.4
0
–18
–5
14
23.8
–9
UNITS
GHz
GHz
–14
–12
–158.2
–152.5
–151.1
10.6
–4
0
–28
8.5
49
22.8
–40
–49
–58
–10
EN = High (Note 6)
EN = Low (Note 6)
(Note 5) at 2GHz
(Note 5) at 2GHz
(Note 5) at 2GHz
TYP
dB
dB
dBm/Hz
dBm/Hz
dBm/Hz
dB
dB
dBm
dB
dBm
dBm
dBm
dBc
dBm
dBm
5
GHz
dBm
dB
dB
dB
dB
dBm
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
Baseband Inputs (BBPI, BBMI, BBPQ, BBMQ)
Baseband Bandwidth
BWBB
VCMBB
DC Common Mode Voltage
RIN, DIFF
Differential Input Resistance
RIN, CM
Common Mode Input Resistance
ICM, COMP
Common Mode Compliance Current Range
PLO2BB
Carrier Feedthrough on BB
IP1dB
Input 1dB Compression Point
ΔGI/Q
I/Q Absolute Gain Imbalance
ΔφI/Q
I/Q Absolute Phase Imbalance
Power Supply (VCC)
VCC
Supply Voltage
ICC, ON
Supply Current
ICC, OFF
Supply Current, Sleep Mode
tON
Turn-On Time
tOFF
Turn-Off Time
Enable (EN), Low = Off, High = On
Enable
Input High Voltage
Input High Current
Sleep
Input Low Voltage
CONDITIONS
MIN
–3dB Bandwidth
(Note 4)
Between BBPI and BBMI (or BBPQ and BBMQ)
BBPX and BBMX Shorted Together
BBPX and BBMX Shorted Together (Note 18)
POUT = 0 (Note 4)
Differential Peak-to-Peak (Note 7)
EN = High
EN = 0V
EN = Low to High (Note 11)
EN = High to Low (Note 12)
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) = 1VDC, V(BBPQ) – V(BBMQ) = 1VDC.
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.
MAX
400
2.06
2.9
105
–730 to 480
–40
2.7
0.06
1
4.5
EN = High
EN = 5V
EN = Low
TYP
5
128
0.05
0.2
1.3
UNITS
MHz
V
kΩ
Ω
µA
dBm
VP-P, DIFF
dB
deg
5.25
145
50
1.0
240
0.5
V
mA
µA
µs
µs
V
µA
V
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
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LT5518
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TYPICAL PERFOR A CE CHARACTERISTICS
VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz,
PLO = 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
Compression vs LO Frequency
at 1VP-P Differential Baseband Drive
and Temperature
Supply Current vs Supply Voltage
140
5
15
4.5V
5.5V
5V
TA = 25°C
120
TA = –40°C
110
100
4.5
5.0
0
–5
–10
–15
1.3
5.5
5V, TA = –40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
1.5
SUPPLY VOLTAGE (V)
1.7
1.9
2.1
2.3
LO FREQUENCY (GHz)
2.5
Voltage Gain and Output 1dB
Compression vs LO Frequency
and Supply Voltage
26
4.5V
5.5V
5V
22
fBB, 1 = 2MHz
fBB, 2 = 2.1MHz
20
OIP3 (dBm)
GAIN
– 10
– 15
1.3
1.5
2.3
1.7 1.9 2.1
LO FREQUENCY (GHz)
2.5
2.7
18
22
2.7
5518 G07
–148
–150
fBB, 1 = 2MHz
fBB, 2 = 2.1MHz
20
–152
18
–154
16
–156
14 NOISE FLOOR
–158
12
–160
–160
–162
10
–162
8
NO BASEBAND SIGNAL
–164
fLO = 2.14GHz (FIXED) FOR NOISE
–166
2.5
2.7
2.3
1.7 1.9 2.1
8
NO BASEBAND SIGNAL
–164
fLO = 2.14GHz (FIXED) FOR NOISE
–166
2.5
2.7
2.3
1.7 1.9 2.1
6
1.3
1.5
6
1.3
1.5
LO/NOISE FREQUENCY (GHz)
5518 G05
5518 G06
3 • LO Leakage to RF Output vs
3 • LO Frequency
–30
5V, TA = –40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
–35
–40
–35
P(3 • LO) (dBm)
P(2 • LO) (dBm)
2.5
–146
4.5V
5.5V
5V
10
– 45
LO FT (dBm)
OIP3
24
12
–30
2.3
1.7 1.9 2.1
LO FREQUENCY (GHz)
–154
2.7
2.5
–158
–25
1.5
1.9 2.1 2.3
LO FREQUENCY (GHz)
14 NOISE FLOOR
– 40
1.3
–152
26
2 • LO Leakage to RF Output vs
2 • LO Frequency
5V, TA = –40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
1.7
Output IP3 and Noise Floor vs LO
Frequency and Supply Voltage
LO/NOISE FREQUENCY (GHz)
– 50
1.5
–156
LO Feedthrough to RF Output vs
LO Frequency
– 60
–10
16
5518 G04
– 55
GAIN
–5
–40
–45
–45
–50
–55
–60
–50
–55
2.6
–65
3.0
NOISE FLOOR (dBm/Hz)
–5
–146
TA = –40°C
TA = 85°C –148
TA = 25°C
–150
OIP3
24
5
0
0
5518 G03
Output IP3 and Noise Floor vs LO
Frequency and Temperature
NOISE FLOOR (dBm/Hz)
VOLTAGE GAIN (dB), OP1dB (dBm)
15
OP1dB
5
5518 G02
5518 G01
10
10 OP1dB
–15
1.3
2.7
OIP3 (dBm)
130
VOLTAGE GAIN (dB), OP1dB (dBm)
RF OUTPUT POWER (dBm)
SUPPLY CURRENT (mA)
TA = 85°C
5.0
4.6
3.4 3.8 4.2
2 • LO FREQUENCY (GHz)
5.4
5518 G08
–70
3.9
5V, TA = –40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
4.5
5.1
5.7
6.3
6.9
7.5
8.1
3 • LO FREQUENCY (GHz)
5518 G09
5518f
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LT5518
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TYPICAL PERFOR A CE CHARACTERISTICS
VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz,
PLO = 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
02
ABSOLUTE I/Q GAIN IMBALANCE (dB)
–25
IMAGE REJECTION (dBc)
–30
–35
–40
–45
–50
–55
1.3
5V, TA = – 40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
1.5
1.7
1.9
2.1
2.3
LO FREQUENCY (GHz)
5
5V, TA = –40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
0.1
0
1.3
2.7
2.5
1.5
1.7
1.9
2.1
2.3
LO FREQUENCY (GHz)
5518 G10
24
–4
22
16
14
12
10
5V, TA = –40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
5V, TA = –40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
8
6
4
0
–20 –16 –12 –8 –4
4
LO INPUT POWER (dBm)
8
5518 G13
–20
HD2
–30
HD2 = MAX POWER AT
fLO + 2 • fBB OR fLO – 2 • fBB –40
– 60
HD3 = MAX POWER AT
fLO + 3 • fBB OR fLO – 3 • fBB
– 70
–50
5
0
2
3
4
1
I AND Q BASEBAND VOLTAGE (VP-P, DIFF)
5518 G16
0
TA = – 40°C – 10
TA = 85°C
TA = 25°C
– 20
HD2
–50
– 30
HD2 = MAX POWER AT
fLO + 2 • fBB OR fLO – 2 • fBB – 40
–60
HD3 = MAX POWER AT
fLO + 3 • fBB OR fLO – 3 • fBB
–70
– 50
0
2
3
4
5
1
I AND Q BASEBAND VOLTAGE (VP-P, DIFF)
8
5518 G15
LO Feedthrough to RF Output and
Image Rejection vs Baseband
Voltage and Supply Voltage
–25
4.5V
5.5V
5V
LO FT
–30
–35
–40
–45
–50
LO FT
–35
–40
–45
IR
IR
–55
2.7
2.5
HD3
–40
LO FT (dBm), IR (dBc)
–10
TA = –40°C
TA = 85°C
TA = 25°C
–30
LO FT (dBm), IR (dBc)
– 40
– 50
–25
RF CW OUTPUT POWER (dBm)
0
HD3
4.5V
5.5V
5V
1.9 2.1 2.3
LO FREQUENCY (GHz)
–30
LO Feedthrough to RF Output and
Image Rejection vs Baseband
Voltage and Temperature
10
– 30
RF
5518 G14
RF CW Output Power, HD2 and
HD3 vs Baseband Voltage and
Supply Voltage
RF
1.7
10
–20
HD2, HD3 (dBc)
OIP3 (dBm)
VOLTAGE GAIN (dB)
–12
– 20
1.5
RF CW OUTPUT POWER (dBm)
–10
– 10
1
–10
18
–8
–18
0
4
–20 –16 –12 – 8 –4
LO INPUT POWER (dBm)
2
RF CW Output Power, HD2 and HD3 vs
Baseband Voltage and Temperature
20
–6
–16
3
5518 G12
Output IP3 vs LO Power
–2
–14
4
0
1.3
2.7
2.5
5V, TA = – 40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
5518 G11
Voltage Gain vs LO Power
HD2, HD3 (dBc)
Absolute I/Q Phase Imbalance
vs LO Frequency
ABSOLUTE I/Q PHASE IMBALANCE (DEG)
Image Rejection vs LO Frequency
–50
0
5
3
4
2
1
I AND Q BASEBAND VOLTAGE (VP-P, DIFF)
5518 G17
–55
0
5
2
3
4
1
I AND Q BASEBAND VOLTAGE (VP-P, DIFF)
5518 G18
5518f
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LT5518
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TYPICAL PERFOR A CE CHARACTERISTICS
VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz,
PLO = 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
0
fBB,1 = 2MHz
fBB,2 = 2.1MHz
fIM2 = fBB,1+ fBB,2 + fLO
60
LO PORT, EN = LOW
–10
S11 (dB)
OIP2 (dBm)
55
50
45
35
1.3
1.5
2.3
1.7 1.9 2.1
LO FREQUENCY (GHz)
–30
–40
2.5
2.7
5518 G19
–50
1.3
LO PORT,
EN = HIGH
RF PORT, EN =
HIGH, NO LO
RF PORT, EN = HIGH,
PLO = 0dBm
5V, TA = –40°C
5V, TA = 25°C
5V, TA = 85°C
4.5V, TA = 25°C
5.5V, TA = 25°C
40
–20
1.5
RF PORT,
EN = LOW
1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
2.5
2.7
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.
GND (Pins 2, 4, 6, 9, 10, 12, 15): Ground. Pins 6, 9, 15
and 17 (exposed pad) are connected to each other internally.
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.
LO (Pin 3): LO Input. The LO input is an AC-coupled singleended input with approximately 50Ω input impedance at
RF frequencies. Externally applied DC voltage should be
within the range –0.5V to VCC + 0.5V in order to avoid
turning on ESD protection diodes.
BBPQ, BBMQ (Pins 7, 5): Baseband Inputs for the Q-Channel, with 2.9kΩ Differential Input Impedance. Internally
biased at about 2.06V. Applied common mode voltage
must stay below 2.5V.
VCC (Pins 8, 13): Power Supply. Pins 8 and 13 are connected 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 impedance at RF frequencies. Externally applied DC voltage
should be within the range –0.5V to VCC + 0.5V in order
to avoid turning on ESD protection diodes.
BBPI, BBMI (Pins 14, 16): Baseband Inputs for the I-Channel, with 2.9kΩ Differential Input Impedance. Internally
biased at about 2.06V. Applied common mode voltage
must stay below 2.5V.
Exposed Pad (Pin 17): Ground. This pin must be soldered
to the printed circuit board ground plane.
5518f
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LT5518
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BLOCK DIAGRA
VCC
8
13
LT5518
BBPI 14
V-I
BBMI 16
11 RF
0°
90°
BALUN
BBPQ 7
1 EN
V-I
BBMQ 5
2
4
6
9
3
GND
10
12
15
17
5518 BD
GND
LO
U
W
U
U
APPLICATIO S I FOR ATIO
The LT5518 consists of I and Q input differential voltageto-current converters, I and Q up-conversion mixers, an
RF output balun, an LO quadrature phase generator and
LO buffers.
External I and Q baseband signals are applied to the differential baseband input pins, BBPI, BBMI, and BBPQ,
BBMQ. These voltage signals are converted to currents and
translated to RF frequency by means of double-balanced
up-converting mixers. The mixer outputs are combined
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 input 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 upconversion mixers. Both the LO input and RF output are
single-ended, 50Ω-matched and AC coupled.
LT5518
RF
C
VCC = 5V
BALUN
FROM
Q
LOMI
LOPI
200Ω
BBPI
VREF = 500mV
1.8pF
1.3k
CM
1.8pF
1.3k
200Ω
BBMI
5518 F01
GND
Figure 1. Simplified Circuit Schematic of the LT5518 (Only I-Half is Drawn)
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Baseband Interface
The baseband inputs (BBPI, BBMI), (BBPQ, BBMQ) present 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
(–1dB point). The common mode voltage is about 2.06V
and is slightly temperature dependent. At TA = –40oC, the
common mode voltage is about 2.19V and at TA = 85oC
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
the common mode voltage independently. In this case, 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).
50Ω
50Ω
1.03VDC
+
–
2.06VDC
GENERATOR
50Ω
1.5k
2.06VDC
+
–
2.06VDC
GENERATOR
2.06VDC
+
–
LT5518
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
The LT5518 should be driven differentially; otherwise, the
even-order distortion products will degrade the overall
linearity severely. Typically, a DAC will be the signal source
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 application. 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
DAC’s differential output current to minimize the LO to RF
feedthrough. Resistors R3A, R3B, R4A and R4B translate
the DAC’s output common mode level from about 0.5VDC
to the LT5518’s input at about 2.06VDC. For these resistors, 1% accuracy is recommended. For different ambient 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
gain difference between low frequency and high frequency
baseband signals. The high frequency baseband –3dB
corner point is approximately given by:
f–3dB = 1/[2π • C4A • (R3A||R4A||(RIN, DIFF/2)]
In this example, f–3dB = 58kHz.
This corner point should be set significantly lower than the
minimum baseband signal frequency by choosing large
enough capacitors C4A and C4B. For signal frequencies
significantly lower than f–3dB, the gain is reduced by approximately
GDC = 20 • log [R3A||(RIN, DIFF/2)]/[R3A||(RIN, DIFF/2)
+ R4A]
In this example, GDC = –11dB.
Inserting the network of R3A, R3B, R4A, R4B, C4A and
C4B has the following consequences:
• Reduced LO feedthrough adjustment range. LO to RF
feedthrough can be reduced by adjusting the differential
DC offset voltage applied to the I and/or Q inputs. Because of the DC gain reduction, the range of adjustment
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
that case, a DC-coupled level shifting circuit is required,
or the LT5528 might be a better solution.
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• Introduction of a (low frequency) time constant during 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 approximately given by TD = RIN, CM • (C4A + C4B). In
this example it will result in a delay of about TD = 105
• 6.6n = 693ns.
will increase the voltage on the DAC output by dumping
an extra current into resistors R1A, R1B, R2A and R2B.
This current is about (VCC – VDAC)/(R3A + R4A) = (5
– 0.5)/(3.01k + 5.63k) = 0.52mA. Maximum impedance
to ground will then be VCOMPL/(IMAX + ILS) = 1.25/0.02052
= 60.9Ω.
4. Reflection of out-of-band baseband signal power. DAC
output signal components higher than the cut-off frequency
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
shunt the DAC higher frequency components and thereby,
limit the required extra voltage headroom.
The maximum sinusoidal single sideband RF output power
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 (VCOMPL) which is
assumed here to be 1.25V. When the DAC output voltage
swing is larger than this compliance voltage, the baseband
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
compliance range of the DAC is –1V to 1.25V, so the DAC’s
output voltage will stay within this range. Almost 6dB extra
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 VCOMPL/IMAX = 1.25/0.02 = 62.5Ω,
the compliance voltage is exceeded for a full DAC swing. In
Figure 3, two 100Ω resistors in parallel are used, 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 IMAX/8 = 2.5mA, then the maximum DC DAC load impedance to ground is reduced to
VCOMPL/IMAX • (1 + 1/8) = 1.25/0.0225 = 55Ω.
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
VCC
5V
C
BALUN
FROM
Q
LOMI
C4A
3.3nF
L1A
0mA TO 20mA
L2A
R1A
100Ω
DAC
C1
0mA TO 20mA
R1B
100Ω
C2
L1B
LOPI
0.53VDC
200Ω
BBPI
VREF = 500mV
2.1VDC
R2A R4A
100Ω 3.01k
R3A
5.63k
R2B
100Ω R4B
3.01k
R3B
5.63k
BBMI
1.8pF
1.3k
CM
C3
L2B
1.8pF
1.3k
200Ω
2.1VDC
0.53VDC
GND
5518 F03
C4B
3.3nF
GND
Figure 3. LT5518 5th Order Filtered Baseband Interface with Common DAC (Only I-Channel is Shown)
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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:
VCC
20pF
LO
INPUT
ZIN ≈ 57Ω
5518 F05
Figure 5. Equivalent Circuit Schematic of the LO Input
• The baseband drive capability cannot be improved using
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 quadrature 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
will degrade, especially below –5dBm and at TA = 85°C.
For high LO input power (e.g. 5dBm), the LO feedthrough
will increase, without improvement in linearity or gain.
Harmonics present on the LO signal can degrade the image
rejection, because they introduce a small excess phase shift
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.
• GDC and f–3dB are a little different, since R3A (and R3B)
is 4.99k instead of 5.6k to accommodate the proper
DC level shift.
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
and Q mixers. The phase relationship between the LO input
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
VCC
5V
C
BALUN
FROM
Q
LOMI
C4A
3.3nF
3.3V
0mA TO
20mA
L1A
L2A
LOPI
3.3VDC
DAC
C1
L1B
0mA TO
20mA
C2
C3
VREF = 500mV
2.1VDC
R3A
4.99k
1.8pF
1.3k
CM
GND
R4B
3.01k
L2B
200Ω
BBPI
R4A
3.01k
R3B
4.99k
BBMI
1.8pF
1.3k
200Ω
2.1VDC
3.3VDC
5518 F04
C4B
3.3nF
GND
Figure 4. LT5518 5th Order Filtered Baseband Interface with 3.3VCM DAC (Only I-Channel is Shown).
10
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Table 1. LO Port Input Impedance vs Frequency for EN = High
Frequency
MHz
1000
1400
1600
1800
2000
2200
2400
2600
Input Impedance
Ω
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
S11
Mag
0.197
0.112
0.113
0.136
0.157
0.161
0.159
0.165
Angle
95
30
–2.4
–32
–58
–77
–94
–109
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
Frequency
MHz
1000
1400
1600
1800
2000
2200
2400
2600
Input Impedance
Ω
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
S11
Mag
0.439
0.454
0.483
0.510
0.532
0.544
0.550
0.553
Angle
75
15
–11
–33
–53
–70
–87
–104
RF Section
After up-conversion, the RF outputs of the I and Q mixers are
combined. An on-chip balun performs internal differential
to single-ended output conversion, while transforming the
output signal impedance to 50Ω. Table 3 shows the RF
port output impedance vs frequency.
The RF output S22 with no LO power applied is given in
Table 4.
Table 4. RF Port Output Impedance vs Frequency for EN = High
and No LO Power Applied
Frequency
MHz
1000
1400
1600
1800
2000
2200
2400
2600
Input Impedance
Ω
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
Input Impedance
Ω
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
Table 5. RF Port Output Impedance vs Frequency for EN = Low
Frequency
MHz
1000
1400
1600
1800
2000
2200
2400
2600
Input Impedance
Ω
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
S22
Mag
0.428
0.365
0.311
0.229
0.116
0.013
0.115
0.193
Angle
153
121
100
77.1
65.5
–179
171
159
Angle
154
123
103
80.2
56.7
158.9
–179
167
To improve S22 for lower frequencies, a shunt capacitor
can be added to the RF output. At higher frequencies, a
shunt inductor can improve the S22. Figure 6 shows the
equivalent circuit schematic of the RF output.
VCC
20pF
RF
OUTPUT
S22
Mag
0.421
0.348
0.280
0.180
0.057
0.073
0.164
0.228
Angle
153
119
102
103
154
160
152
144
For EN = Low the S22 is given in Table 5.
Table 3. RF Port Output Impedance vs Frequency for EN = High
and PLO = 0dBm
Frequency
MHz
1000
1400
1600
1800
2000
2200
2400
2600
S22
Mag
0.416
0.312
0.214
0.104
0.098
0.170
0.226
0.264
52.5Ω
21pF
3nH
5518 F06
Figure 6. Equivalent Circuit Schematic of the RF Output
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 impedance is connected directly to ground. To prevent this, a
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J1
J2
BBIM
BBIP
VCC
coupling capacitor can be inserted in the RF output line.
This is strongly recommended during a 1dB compression
measurement.
16
R1
100
1
VCC EN
Enable Interface
Figure 7 shows a simplified schematic of the EN pin interface. 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
voltage at the EN pin does not exceed VCC by more than
0.5V. If this should occur, the full chip supply current could
be sourced through the EN pin ESD protection diodes.
Damage to the chip may result.
LT5518
6
7
8
C1
100nF
J5
BBQM
GND
J6
BBQP
BOARD NUMBER: DC729A
5518 F08
Figure 8. Evaluation Board Circuit Schematic
R3
3.01k
J1
R4
3.01k
J2
BBIM
BBIP
R5
52.3Ω
C1
3.3nF
R7
100
25k
VCC EN
E1
J4
LO
IN
C2
3.3nF
R1
5.62k
16
15
R6
52.3Ω
14
R2
5.62k
1
EN
2
GND
GND
3
RF
LT5518
LO
4
GND
GND
GND
GND
BBMQ GND BBPQ VCC
Figure 7. EN Pin Interface
R10
3.01k
J5
5
BBQM
R12
52.3Ω
6
7
12
11
10
J3
RF
OUT
9
17
8
C4
100nF
R8
5.62k
C5
3.3nF
VCC
E2
C3
100nF
13
BBMI GND BBPI VCC
5518 F07
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 sinking 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 VCC
inputs are low. In Figures 10, 11 and 12 the silk screen
and the demo board PCB layouts are shown. If improved
LO and Image suppression is required, an LO feedthrough
calibration and an Image suppression calibration can be
performed.
17
GND
BBMQ GND BBPQ VCC
EN
Figure 8 shows the schematic of the evaluation board that
was used for the measurements summarized in the Electrical Characteristics tables and the Typical Performance
Characteristic plots.
9
GND
5
RF
OUT
10
GND
GND
J3
11
RF
BOARD NUMBER: DC831A
Evaluation and Demo Boards
12
GND
LO
4
VCC
75k
C2
100nF
13
GND
3
LO
IN
14
EN
2
J4
15
BBMI GND BBPI VCC
R9
5.62k
R11
3.01k
J6
BBQP
GND
E4
GND
E3
C6
3.3nF
R13
52.3Ω
5518 F09
Figure 9. Demo Board Circuit Schematic
Figure 10. Component Side Silk Screen of Demo Board
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Figure 11. Component Side Layout of Demo Board
Figure 12. Bottom Side Layout of Demo Board
5V
100nF
×2
RF = 1.5GHz
TO 2.4GHz
VCC 8, 13
LT5518
14
I-DAC
16
V-I
I-CHANNEL
EN
1
90°
7
Q-DAC
11
5
PA
0°
Q-CHANNEL
BALUN
LO FEEDTHROUGH CAL OUT
V-I
IMAGE CAL OUT
CAL
BASEBAND
GENERATOR
2, 4, 6, 9, 10, 12, 15, 17
3
VCO/SYNTHESIZER
ADC
5518 F13
Figure 13. 1.5GHz to 2.4GHz Direct Conversion Transmitter
Application with LO Feedthrough and Image Calibration Loop
Application Measurements
The LT5518 is recommended for base-station applications
using various modulation formats. Figure 13 shows a
typical application. The CAL box in Figure 13 allows for
LO feedthrough and Image suppression calibration. Figure 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.
If the output power is high, the ACPR will be limited by the
linearity performance of the part. If the output power is
low, the ACPR will be limited by the noise performance of
the part. In the middle, an optimum ACPR is obtained.
Because of the LT5518’s very high dynamic range, the test
equipment can limit the accuracy of the ACPR measurement. Consult the factory for advice on ACPR measurement, if needed.
The ACPR performance is sensitive to the amplitude match
of the BBIP and BBIM (or BBQP and BBQM) input voltage.
This is because a difference in AC voltage amplitude will
give rise to a difference in amplitude between the even-order
harmonic products generated in the internal V-I converter.
As a result, they will not cancel out entirely. Therefore, it
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is important to keep the amplitudes at the BBIP and BBIM
inputs (or BBQP and BBQM) as equal as possible.
When the temperature is changed after calibration, the LO
feedthrough and the Image Rejection performance will
change. This is illustrated in Figure 18. The LO feedthrough
–30
–135
–60
–140
4-CH ALTCPR
–145
–65
1-CH ACPR
–70
–150
–75
–155
1-CH ALTCPR
–80
1-CH NOISE
–160
4-CH NOISE
DOWNLINK TEST MODEL 64 DPCH
–85
–34 –30 –26 –22 –18
–14 –10
RF OUTPUT POWER PER CARRIER (dBm)
NOISE FLOOR AT 30MHz OFFSET (dBm/Hz)
4-CH ACPR
DOWNLINK TEST
MODEL 64 DPCH
–40
POWER IN 30kHz BW (dBm)
–55
ACPR, ALTCPR (dBc)
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.
–50
–60
–70
–80
–90
UNCORRECTED
SPECTRUM
CORRECTED
SPECTRUM
–100
–110
–120
2127.5
–165
SYSTEM NOISE FLOOR
2132.5 2137.5 2142.5 2147.5 2152.5
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
–50
–60
–70
–80
UNCORRECTED
SPECTRUM
–90
–100
CORRECTED
SPECTRUM
–110
UNCORRECTED
SPECTRUM
–50
POWER IN 30kHz BW (dBm)
POWER IN 30kHz BW (dBm)
–40
–60
SYSTEM NOISE FLOOR
2130
2135 2140 2145 2150
RF FREQUENCY (MHz)
2155
5518 F16
Figure 16. 2-Channel W-CDMA
Spectrum
DOWNLINK
TEST
MODEL 64
DPCH
–70
–80
CORRECTED
SPECTRUM
–90
–100
–110
SYSTEM NOISE FLOOR
–120
–120
2125
–40
–40
DOWNLINK TEST
MODEL 64 DPCH
–130
2115
2125
CALIBRATED WITH PRF = –30dBm
–45
IMAGE REJECTION
–50
–55
LO FT (dBm), IR (dB)
–30
Figure 15. 1-Channel W-CDMA Spectrum
–60
–65
LO FEEDTHROUGH
–70
–75
–80
–85
2135
2145
2155
RF FREQUENCY (MHz)
2165
5518 F17
Figure 17. 4-Channel W-CDMA
Spectrum
–90
–40
–20
0
20
40
TEMPERATURE (°C)
60
80
5518 F18
Figure 18. LO Feedthrough and
Image Rejection vs Temperature
after Calibration at 25°C
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20
10
PRF
10
IM3
–10
–20
– 20
HD2, HD3 (dBc)
PRF, LO FT (dBm), IR (dBc)
0
–10
LO FT
– 30
– 40
– 50
fBBI = 2MHz, 0°
fBBQ = 2MHz, 90°
PLO = 0dBm
f =f +f
TA = –40°C RF BB LO
fLO = 2.14GHz
TA = 85°C
VCC = 5V
TA = 25°C
EN = HIGH
1
3
4
5
2
I AND Q BASEBAND VOLTAGE (VP-P, DIFF)
5518 F19
IR
– 60
– 70
– 80
– 90
RF
0
0
–30
IM2
fBBI = 2MHz, 2.1MHz, 0°
fBBQ = 2MHz, 2.1MHz, 90°
PLO = 0dBm
–50
fRF = fBB + fLO
fLO = 2.14GHz
–60
IM2 = POWER AT fLO + 4.1MHz
–70
TA = –40°C IM3 = MAX POWER AT
TA = 85°C fLO + 1.9MHz or fLO + 2.2MHz
–80
TA = 25°C VCC = 5V
EN = HIGH
–90
0.1
1
10
5518 F20
I AND Q BASEBAND VOLTAGE (VP-P, DIFF, EACH TONE)
–40
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)
0.72 ±0.05
4.35 ± 0.05
2.15 ± 0.05
2.90 ± 0.05 (4 SIDES)
NOTE:
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
PACKAGE OUTLINE
0.30 ±0.05
0.65 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
BOTTOM VIEW—EXPOSED PAD
4.00 ± 0.10
(4 SIDES)
0.75 ± 0.05
R = 0.115
TYP
15
PIN 1 NOTCH R = 0.20 TYP
OR 0.35 × 45° CHAMFER
16
0.55 ± 0.20
PIN 1
TOP MARK
(NOTE 6)
1
2.15 ± 0.10
(4-SIDES)
2
(UF16) QFN 10-04
0.200 REF
0.00 – 0.05
0.30 ± 0.05
0.65 BSC
5518f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 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
LT5512
LT5514
DESCRIPTION
COMMENTS
High Linearity Up-Converting Mixer
DC-3GHz High Signal Level Down-Converting Mixer
Ultralow Distortion, IF Amplifier/ADC Driver with
Digitally Controlled Gain
RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer
DC to 3GHz, 17dBm IIP3, Integrated LO Buffer
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
0.7GHz to 1.4GHz High Linearity Up-Converting Mixer
LT5520
1.3GHz to 2.3GHz High Linearity Up-Converting Mixer
LT5521
10MHz to 3700MHz High Linearity Up-Converting Mixer
LT5522
600MHz to 2.7GHz High Signal Level Down-Converting Mixer
LT5524
LT5525
Low Power, Low Distortion ADC Driver with
Digitally Programmable Gain
High Linearity, Low Power Downconverting Mixer
20dBm IIP3, Integrated LO Quadrature Generator
21.5dBm IIP3, Integrated LO Quadrature Generator
21dBm IIP3, Integrated LO Quadrature Generator
17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50Ω
Matching, Single-Ended LO and RF Ports Operation
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
450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control
LT5526
High Linearity, Low Power Downconverting Mixer
LT5528
1.5GHz – 2.4GHz High Linearity Direct Quadrature Modulator
RF Power Detectors
LT5504
800MHz to 2.7GHz RF Measuring Receiver
LTC®5505
RF Power Detectors with >40dB Dynamic Range
LTC5507
100kHz to 1000MHz RF Power Detector
LTC5508
300MHz to 7GHz RF Power Detector
LTC5509
300MHz to 3GHz RF Power Detector
LTC5530
300MHz to 7GHz Precision RF Power Detector
LTC5531
300MHz to 7GHz Precision RF Power Detector
LTC5532
300MHz to 7GHz Precision RF Power Detector
LT5534
50MHz to 3GHz RF Power Detector with 60dB Dynamic Range
Low Voltage RF Building Block
LT5546
500MHz Quadrature Demodulator with VGA
and 17MHz Baseband Bandwidth
Wide Bandwidth ADCs
LT1749
12-Bit, 80Msps
LT1750
14-Bit, 80Msps
Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz,
ICC = 28mA
3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB,
ICC = 28mA
4.5V to 5.25V Supply, 22dBm OIP3 at 2GHz, NFloor = 159dBm/Hz,
50Ω Single-Ended BB, RF and LO Ports
80dB Dynamic Range, Temperature Compensated,
2.7V to 5.25V Supply
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
Precision VOUT Offset Control, Shutdown, Adjustable Gain
Precision VOUT Offset Control, Shutdown, Adjustable Offset
Precision VOUT Offset Control, Adjustable Gain and Offset
±1dB Output Variation Overtemperature, 38ns Response Time
17MHz Baseband Bandwidth, 40MHz to 500MHz IF,
1.8V to 5.25V Supply, –7dB to 56dB Linear Power Gain
500MHz BW S/H, 71.8dB SNR
500MHz BW S/H, 75.5dB SNR
5518f
16 Linear Technology Corporation
LT/TP 0205 1K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005