LINER LT5517 800mhz to 2.7ghz high linearity direct conversion quadrature demodulator Datasheet

LT5575
800MHz to 2.7GHz
High Linearity Direct Conversion
Quadrature Demodulator
DESCRIPTION
FEATURES
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Input Frequency Range: 0.8GHz to 2.7GHz*
50Ω Single-Ended RF and LO Ports
High IIP3: 28dBm at 900MHz, 22.6dBm at 1.9GHz
High IIP2: 54.1dBm at 900MHz, 60dBm at 1.9GHz
Input P1dB: 13.2dBm at 900MHz
I/Q Gain Mismatch: 0.04dB Typical
I/Q Phase Mismatch: 0.4° Typical
Low Output DC Offsets
Noise Figure: 12.8dB at 900MHz, 12.7dB at 1.9GHz
Conversion Gain: 3dB at 900MHz, 4.2dB at 1.9GHz
Very Few External Components
Shutdown Mode
16-Lead QFN 4mm × 4mm Package with
Exposed Pad
The LT®5575 is an 800MHz to 2.7GHz direct conversion
quadrature demodulator optimized for high linearity
receiver applications. It is suitable for communications
receivers where an RF signal is directly converted into I
and Q baseband signals with bandwidth up to 490MHz.
The LT5575 incorporates balanced I and Q mixers, LO
buffer amplifiers and a precision, high frequency quadrature
phase shifter. The integrated on-chip broadband transformers provide 50Ω single-ended interfaces at the RF and LO
inputs. Only a few external capacitors are needed for its
application in an RF receiver system.
The high linearity of the LT5575 provides excellent spurfree dynamic range for the receiver. This direct conversion
demodulator can eliminate the need for intermediate frequency (IF) signal processing, as well as the corresponding
requirements for image filtering and IF filtering. Channel
filtering can be performed directly at the outputs of the I
and Q channels. These outputs can interface directly to
channel-select filters (LPFs) or to baseband amplifiers.
APPLICATIONS
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Cellular/PCS/UMTS Infrastructure
RFID Reader
High Linearity Direct Conversion I/Q Receiver
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Operation over a wider frequency range is possible with reduced performance. Consult
the factory.
TYPICAL APPLICATION
Conversion Gain, NF, IIP3 and IIP2
vs LO Input Power at 1900MHz
High Signal-Level I/Q Demodulator for Wireless Infrastructure
+5V
BPF
RF
INPUT
LNA
IOUT+
RF
LPF
VGA
0°
A/D
IOUT–
LO
0°/90°
90°
QOUT+
LPF
VGA
A/D
30
60
25
50
IIP3
20
40
DSB NF
15
10
5
–40°C
25°C
85°C
30
IIP2 (dBm)
LO INPUT
70
IIP2
LT5575
GAIN (dB), NF (dB), IIP3 (dBm)
BPF
35
VCC
20
CONV
GAIN
10
QOUT–
ENABLE
EN
5575 TA01
0
–15
–5
–10
0
LO INPUT POWER (dBm)
5
0
5575 TA01b
5575f
1
LT5575
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS
(Note 1)
QOUT–
QOUT+
IOUT+
IOUT–
TOP VIEW
Power Supply Voltage ..............................................5.5V
Enable Voltage ................................ –0.3V to VCC + 0.3V
LO Input Power ....................................................10dBm
RF Input Power ....................................................20dBm
RF Input DC Voltage ...............................................±0.1V
LO Input DC Voltage ..............................................±0.1V
Operating Ambient Temperature ..............–40°C to 85°C
Storage Temperature Range...................–65°C to 125°C
Maximum Junction Temperature .......................... 125°C
16 15 14 13
GND 1
12 VCC
RF 2
11 GND
17
GND 3
10 LO
GND 4
6
7
8
EN
VCC
VCC
VCC
9
5
GND
UF PACKAGE
16-LEAD (4mm × 4mm) PLASTIC QFN
TJMAX = 125°C, θJA = 37°C/W
EXPOSED PAD (PIN #17) IS GND, MUST BE SOLDERED TO PCB
CAUTION: This part is sensitive to electrostatic discharge
(ESD). It is very important that proper ESD precautions
be observed when handling the LT5575.
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT5575EUF#PBF
LT5575EUF#TRPBF
5575
16-Lead (4mm × 4mm) QFN
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
DC ELECTRICAL CHARACTERISTICS
PARAMETER
VCC = +5V, TA = 25°C, unless otherwise noted. (Note 3)
CONDITIONS
MIN
MAX
UNITS
5.25
V
132
155
mA
<1
100
µA
4.5
Supply Voltage
Supply Current
Shutdown Current
TYP
EN = Low
Turn On Time
120
ns
Turn Off Time
750
ns
EN = High (On)
2
V
EN = Low (Off)
1
V
EN Input Current
VENABLE = 5V
120
µA
Output DC Offset Voltage
( | IOUT+ – IOUT– |, | QOUT+ – QOUT– | )
fLO = 1900MHz, PLO = 0dBm
<9
mV
Output DC Offset Variation
vs Temperature
–40°C to 85°C
38
µV/°C
5575f
2
LT5575
AC ELECTRICAL CHARACTERISTICS
Test circuit shown in Figure 1. (Notes 2, 3)
PARAMETER
CONDITIONS
MIN
RF Input Frequency Range
No External Matching (High Band)
With External Matching (Low Band, Mid Band)
1.5 to 2.7
0.8 to 1.5
GHz
GHz
LO Input Frequency Range
No External Matching (High Band)
With External Matching (Low Band, Mid Band)
1.5 to 2.7
0.8 to 1.5
GHz
GHz
DC to 490
MHz
Baseband Frequency Range
TYP
MAX
UNITS
65Ω// 5pF
Baseband I/Q Output Impedance
Single-Ended
RF Input Return Loss
ZO = 50Ω, 1.5GHz to 2.7GHz,
Internally Matched
>10
dB
LO Input Return Loss
ZO = 50Ω, 1.5GHz to 2.7GHz,
Internally Matched
>10
dB
LO Input Power
–13 to 5
dBm
AC ELECTRICAL CHARACTERISTICS
VCC = +5V, EN = High, TA = 25°C, PRF = –10dBm (–10dBm/tone for
2-tone IIP2 and IIP3 tests), Baseband Frequency = 1MHz (0.9MHz and 1.1MHz for 2-tone tests), PLO = 0dBm, unless otherwise noted.
(Notes 2, 3, 6)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Conversion Gain
Voltage Gain, RLOAD = 1kΩ
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
3
4.2
3.5
2
dB
dB
dB
dB
Noise Figure (Double-Side Band, Note 4)
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
12.8
12.7
13.6
15.7
dB
dB
dB
dB
Input 3rd-Order Intercept
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
28
22.6
22.7
23.3
dBm
dBm
dBm
dBm
Input 2nd-Order Intercept
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
54.1
60
56
52.3
dBm
dBm
dBm
dBm
Input 1dB Compression
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
13.2
11.2
11
12.3
dBm
dBm
dBm
dBm
I/Q Gain Mismatch
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
0.03
0.01
0.04
0.04
dB
dB
dB
dB
I/Q Phase Mismatch
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
0.5
0.4
0.6
0.2
°
°
°
°
LO to RF Leakage
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
–60.8
–64.6
–60.2
–51.2
dBm
dBm
dBm
dBm
5575f
3
LT5575
AC ELECTRICAL CHARACTERISTICS
VCC = +5V, EN = High, TA = 25°C, PRF = –10dBm (–10dBm/tone for
2-tone IIP2 and IIP3 tests), Baseband Frequency = 1MHz (0.9MHz and 1.1MHz for 2-tone tests), PLO = 0dBm, unless otherwise noted.
(Notes 2, 3, 6)
PARAMETER
CONDITIONS
RF to LO Isolation
RF = 900MHz (Note 5)
RF = 1900MHz
RF = 2100MHz
RF = 2500MHz
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: Tests are performed as shown in the configuration of Figure 1.
Note 3: Specifications over the –40˚C to 85˚C temperature range are
assured by design, characterization and correlation with statistical
process control.
Note 4: DSB Noise Figure is measured with a small-signal noise source
at the baseband frequency of 15MHz without any filtering on the RF input
and no other RF signal applied.
MIN
TYP
59.7
57.1
59.5
53.1
MAX
UNITS
dBc
dBc
dBc
dBc
Note 5: 900MHz performance is measured with external RF and LO
matching. The optional output capacitors C1-C4 (10pF) are also used for
best IIP2 performance.
Note 6: For these measurements, the complementary outputs (e.g., IOUT +,
IOUT – ) were combined using a 180˚ phase shift combiner.
Note 7: Large-signal noise figure is measured at an output frequency of
198.7MHz with RF input signal at fLO –1MHz. Both RF and LO input signals
are appropriately bandpass filtered, as well as baseband output.
5575f
4
LT5575
TYPICAL AC PERFORMANCE CHARACTERISTICS
VCC = 5V, EN = High, TA = 25ºC, PRF = –10dBm
(–10dBm/tone for 2-tone IIP2 and IIP3 tests), fBB = 1MHz (0.9MHz and 1.1MHz for 2-tone tests), PLO = 0dBm, unless otherwise noted.
Test Circuit Shown in Figure 1 (Note 6).
Conversion Gain, NF and IIP3
vs Frequency
–40°C
25°C
85°C
30
70
160
65
150
60
140
LOW
MID
20 BAND BAND
15
HIGH BAND
DSB NF
ICC (mA)
25
55
50
10
25°C
130
120
– 40°C
CONV GAIN
5
0
800
–40°C
25°C
85°C
45
40
800
1100 1400 1700 2000 2300 2600
RF INPUT FREQUENCY (MHz)
110
100
4.50
1100 1400 1700 2000 2300 2600
RF INPUT FREQUENCY (MHz)
Conversion Gain
vs RF Input Power
0.3
5
1900MHz
fBB = 1MHz
2500MHz
2
1
3
0.1
0.0
–0.1
–0.2
0
–1
–15
–10
10
–5
0
5
RF INPUT POWER (dBm)
–40°C
25°C
85°C
1
0
1
2
–0.3
800
15
fBB = 1MHz
2
PHASE MISMATCH (DEG)
GAIN MISMATCH (dB)
3
I/Q Phase Mismatch
vs RF Input Frequency
–40°C
25°C
85°C
0.2
4
5575 G04
3
800
1100 1400 1700 2000 2300 2600
RF FREQUENCY (MHz)
1100 1400 1700 2000 2300 2600
RF FREQUENCY (MHz)
5575 G05
RF-LO Isolation
vs RF Input Power
6
– 45
900MHz
60
1900MHz
55
2500MHz
50
45
–55
–8
–4
0
RF INPUT POWER (dBm)
4
8
5575 G07
5
– 40°C
25°C
2500MHz
– 60
–65
900MHz
4
85°C
3
2
–70
–75
–12
fLO = 1901MHz
–50
CONV. GAIN (dB)
LO-RF LEAKAGE (dBm)
RF-LO ISOLATION (dBc)
Conversion Gain
vs Baseband Frequency
– 40
65
40
–16
5575 G06
LO-RF Leakage
vs LO Input Power
70
5.50
5575 G03
I/Q Gain Mismatch
vs RF Input Frequency
900MHz
4.75
5.00
5.25
SUPPLY VOLTAGE (V)
5575 G02
5575 G01
CONVERSION GAIN (dB)
85°C
IIP3
IIP2 (dBm)
GAIN (dB), NF (dB), IIP3 (dBm)
35
Supply Current
vs Supply Voltage
IIP2 vs Frequency
– 80
–15
1
1900MHz
–5
–10
0
LO INPUT POWER (dBm)
5
5575 G08
0
0.1
1.0
10
100
BASEBAND FREQUENCY (MHz)
1000
5575 G09
5575f
5
LT5575
TYPICAL AC PERFORMANCE CHARACTERISTICS VCC = 5V, EN = High, TA = 25ºC, PRF = –10dBm
(–10dBm/tone for 2-tone IIP2 and IIP3 tests), fBB = 1MHz (0.9MHz and 1.1MHz for 2-tone tests), PLO = 0dBm, unless otherwise noted.
Test Circuit Shown in Figure 1 (Note 6).
Conversion Gain, IIP3, NF
vs LO Input Power at 900MHz
10
IIP3
30
25
–40°C
25°C
85°C
20
DSB NF
15
10
CONV GAIN
5
0
–15
–5
–10
0
LO INPUT POWER (dBm)
5
70
fLO = 901MHz
–10
OUTPUT POWER
–50
IM3 PRODUCT
–70
–12
–8
–4
0
RF INPUT POWER (dBm)
4
DSB NF
10
CONV. GAIN
5
0
–15
–10
–5
0
LO INPUT POWER (dBm)
5
60
–30
IM3 PRODUCT
–50
50
–70
–40°C
25°C
85°C
–90
–12
–8
–4
0
RF INPUT POWER (dBm)
4
10
5
0
–15
10
40
–15
8
–40°C
25°C
85°C
CONV. GAIN
5
5575 G16
–40°C
25°C
85°C
–10
–5
0
LO INPUT POWER (dBm)
IIP2 vs LO Input Power
at 2500MHz
70
fLO = 2501MHz
fLO = 2501MHz
65
–10
5
5575 G15
OUTPUT POWER
–40°C
25°C
85°C
60
–30
IIP2 (dBm)
DSB NF
–10
–5
0
LO INPUT POWER (dBm)
45
Output Power and IM3
vs RF Input Power at 2500MHz
20
15
55
5575 G14
OUTPUT POWER (dBm), IM3 (dBm)
GAIN (dB), NF (dB), IIP3 (dBm)
25
fLO = 1901MHz
65
OUTPUT POWER
–110
–16
fLO = 2501MHz
5
IIP2 vs LO Input Power
at 1900MHz
70
–10
Conversion. Gain, IIP3, NF
vs LO Input Power at 2500MHz
IIP3
–5
–10
0
LO INPUT POWER (dBm)
5575 G12
fLO = 1901MHz
5575 G13
30
30
–15
8
5575 G11
10
20
15
45
35
IIP2 (dBm)
IIP3
50
40
–40°C
25°C
85°C
–90
–110
–16
OUTPUT POWER (dBm), IM3 (dBm)
GAIN (dB), NF (dB), IIP3 (dBm)
25
55
Output Power and IM3
vs RF Input Power at 1900MHz
–40°C
25°C
85°C
–40°C
25°C
85°C
60
–30
Conversion Gain, IIP3, NF
vs LO Input Power at 1900MHz
fLO = 1901MHz
fLO = 901MHz
65
5575 G10
30
IIP2 vs LO Input Power at 900MHz
IIP2 (dBm)
fLO = 901MHz
OUTPUT POWER (dBm), IM3 (dBm)
GAIN (dB), NF (dB), IIP3 (dBm)
35
Output Power and IM3
vs RF Input Power at 900MHz
IM3 PRODUCT
–50
–70
55
50
45
40
–40°C
25°C
85°C
–90
–110
–16
–12
–8
–4
0
RF INPUT POWER (dBm)
4
35
8
5575 G17
30
–15
–5
–10
0
LO INPUT POWER (dBm)
5
5575 G18
5575f
6
LT5575
TYPICAL AC PERFORMANCE CHARACTERISTICS VCC = 5V, EN = High, TA = 25ºC, PRF = –10dBm
(–10dBm/tone for 2-tone IIP2 and IIP3 tests), fBB = 1MHz (0.9MHz and 1.1MHz for 2-tone tests), PLO = 0dBm, unless otherwise noted.
Test Circuit Shown in Figure 1 (Notes 6, 7).
I/Q Gain Mismatch
vs LO Input Power
3
fBB = 1MHz
30
fBB = 1MHz
2
0.1
PHASE MISMATCH (DEG)
GAIN MISMATCH (dB)
0.2
2500MHz
1900MHz
0.0
900MHz
–0.1
Large-Signal DSB NF
vs RF Input Power
900MHz
1900MHz
2500MHz
NOTE 7
28
26
24
1
DSB NF (dB)
0.3
I/Q Phase Mismatch
vs LO Input Power
0
–1
22
20
18
900MHz
2500MHz
16
1900MHz
14
–0.2
–2
–0.3
–15
–3
–15
12
–10
–5
0
LO INPUT POWER (dBm)
5
–10
–5
0
LO INPUT POWER (dBm)
5575 G19
GAIN (dB), NF (dB), IIP3 (dBm)
35
RETURN LOSS (dB)
–5
–10
–15
LOW BAND;
C10 = 4.7pF
MID BAND;
C10 = 2pF
HIGH BAND;
NO EXTERNAL
COMPONENT
–20
–25
–10
–15
–20
–30
800 1100 1400 1700 2000 2300 2600
FREQUENCY (MHz)
–25
800
LOW BAND; C12 = 3.9pF
MID BAND; C12 = 2.2pF
HIGH BAND;
NO EXTERNAL COMPONENT
15
55
50
45
10
CONV. GAIN
1100 1400 1700 2000 2300 2600
RF FREQUENCY (MHz)
5575 G24
0.2
I/Q Phase Mismatch
vs Supply Voltage
0.1
0.0
–0.1
–0.3
800
3
4.75V
5V
5.25V
–0.2
1100 1400 1700 2000 2300 2600
RF FREQUENCY (MHz)
5575 G25
DSB NF
0
800
2
PHASE MISMATCH (DEG)
0.3
4.75V
5V
5.25V
60
40
800
20
I/Q Gain Mismatch
vs Supply Voltage
GAIN MISMATCH (dB)
65
IIP3
25
5575 G23
IIP2 vs Supply Voltage
70
4.75V
5V
5.25V
30
5
1100 1400 1700 2000 2300 2600
FREQUENCY (MHz)
5575 G22
10
Conversion Gain, IIP3, NF
vs Supply Voltage
0
–5
5
5575 G21
LO Port Return Loss
0
RETURN LOSS (dB)
5
5575 G20
RF Port Return Loss
IIP2 (dBm)
10
0
–30 –25 –20 –15 –10 –5
RF INPUT POWER (dBm)
4.75V
5V
5.25V
1
0
–1
–2
1100 1400 1700 2000 2300 2600
RF FREQUENCY (MHz)
5575 G26
–3
800
1100 1400 1700 2000 2300 2600
RF FREQUENCY (MHz)
5575 G27
5575f
7
LT5575
TYPICAL AC PERFORMANCE CHARACTERISTICS VCC = 5V, EN = High, TA = 25ºC, PRF = –10dBm
(–10dBm/tone for 2-tone IIP2 and IIP3 tests), fBB = 1MHz (0.9MHz and 1.1MHz for 2-tone tests), PLO = 0dBm, unless otherwise noted.
Test Circuit Shown in Figure 1 (Note 6).
Conversion Gain Distribution
at 1900MHz
45
30
TA = 25°C
DISTRIBUTION (%)
DISTRIBUTION (%)
35
30
25
20
15
20
15
10
10
5
0
3.8
3.9
4
4.1 4.2 4.3
CONVERSION GAIN (dB)
4.4
21.4 21.8 22.2 22.6 23 23.4 23.8 24.2 24.6 25
IIP3 (dBm)
I/Q Amplitude Mismatch Distribution
at 1900MHz vs Temperature
25
20
DISTRIBUTION (%)
DISTRIBUTION (%)
20
15
10
0
12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13
DSB NOISE FIGURE (dB)
40
30
20
5575 G30
I/Q Phase Mismatch Distribution
at 1900MHz vs Temperature
–40°C
25°C
85°C
50
25
5575 G29
5575 G28
60
TA = 25°C
30
5
5
0
35
– 40°C
25°C
85°C
25
40
Noise Figure Distribution
at 1900MHz
DISTRIBUTION (%)
50
IIP3 Distribution at 1900MHz
vs Temperature
–40°C
25°C
85°C
15
10
5
10
0
0
–20
20
40
60
0
AMPLITUDE MISMATCH (mdB)
80
–1.2 –0.8 –0.4 0 0.4 0.8 1.2 1.6 2.0 2.2
PHASE MISMATCH (°)
5575 G32
5575 G31
I-Output DC Offset Voltage
Distribution vs Temperature
40
Q-Output DC Offset Voltage
Distribution vs Temperature
40
–40°C
25°C
85°C
35
35
30
DISTRIBUTION (%)
DISTRIBUTION (%)
30
25
20
15
20
15
10
5
5
2
4
6
8 10 12 14
DC OFFSET (mV)
16
18
5575 G33
8
25
10
0
– 40°C
25°C
85°C
0
–10 –8
–6
–4 –2 0
2
DC OFFSET (mV)
4
6
5575 G34
5575f
LT5575
PIN FUNCTIONS
GND (Pins 1, 3, 4, 9, 11): Ground pin.
RF (Pin 2): RF Input Pin. This is a single-ended 50Ω terminated input. No external matching network is required
for the high frequency band. An external series capacitor
(and/or shunt capacitor) may be required for impedance
transformation to 50Ω in the low frequency band from
800MHz to 1.5GHz (see Figure 4). If the RF source is not
DC blocked, a series blocking capacitor should be used.
Otherwise, damage to the IC may result.
VCC (Pins 6, 7, 8, 12): Power Supply Pins. These pins
should be decoupled using 1000pF and 0.1µF capacitors.
EN (Pin 5): Enable Pin. When the input voltage is higher
than 2.0V, the circuit is completely turned on. When the
enable pin voltage is less than 1.0V, the circuit is turned
off. Under no conditions should the voltage at the EN
pin exceed VCC + 0.3V. Otherwise, damage to the IC may
result. If the Enable function is not needed, then the EN
pin should be tied to VCC.
LO (Pin 10): Local Oscillator Input Pin. This is a singleended 50Ω terminated input. No external matching network is required in the high frequency band. An external
shunt capacitor (and/or series capacitor) may be required
for impedance transformation to 50Ω for the low frequency
band from 800MHz to 1.5GHz (see Figure 6). If the LO
source is not DC blocked, a series blocking capacitor must
be used. Otherwise, damage to the IC may result.
QOUT–, QOUT+ (Pins 13, 14): Differential Baseband
Output Pins of the Q Channel. The internal DC bias voltage
is VCC – 1.1V for each pin.
I OUT–, I OUT+ (Pins 15, 16): Differential Baseband
Output Pins of the I Channel. The internal DC bias voltage
is VCC – 1.1V for each pin.
Exposed Pad (Pin 17): Ground Return for the Entire IC.
This pin must be soldered to the printed circuit board
ground plane.
BLOCK DIAGRAM
VCC
VCC
VCC
VCC
6
7
8
12
RF AMP
I-MIXER
LPF
16 IOUT+
15 IOUT–
RF 2
11 GND
LO BUFFERS
0°/90°
GND 3
10 LO
RF AMP
LPF
13 QOUT–
Q-MIXER
1
4
GND
9
14 QOUT+
BIAS
EXPOSED
PAD
5
17
5575 BD
EN
5575f
9
LT5575
TEST CIRCUIT
J3
J5
IOUT–
QOUT+
C2
(OPT)
C4
(OPT)
J4
J6
IOUT+
RF
r = 4.4
RF
GND
QOUT –
QOUT +
LT5575
J2
LO
VCC
GND
VCC
GND
VCC
LO
C5
1nF
C12
(OPT)
C8
0.1µF
C9
2.2µF
VCC
EN
R1
100K
0.062"
0.018"
VCC
GND
GND
EN
C10
(OPT)
0.018"
IOUT –
GND
J1
RF
QOUT–
C1
(OPT)
IOUT +
C3
(OPT)
C7
1nF
DC
GND
5575 F01
REF DES
VALUE
SIZE
PART NUMBER
C5, C7
1000pF
0402
AVX 04025C102JAT
C8
0.1µF
0402
AVX 0402ZD104KAT
C9
2.2µF
3216
AVX TPSA225MO10R1800
R1
100kΩ
0402
RF MATCH
LO MATCH
BASEBAND
C10
C12
C1-C4
LOW BAND:
800 TO 1000MHz
4.7pF
3.9pF
10pF
MID BAND:
1000 TO 1500MHz
2pF
2pF
2.2pF
HIGH BAND:
1500 TO 2700MHz
-
-
-
FREQUENCY
RANGE
Figure 1. Evaluation Circuit Schematic
5575 F02
Figure 2. Top Side of Evaluation Board
5575 F03
Figure 3. Bottom Side of Evaluation Board
5575f
10
LT5575
APPLICATIONS INFORMATION
The RF signal is applied to the inputs of the RF
transconductance amplifiers and is then demodulated
into I/Q baseband signals using quadrature LO signals
which are internally generated from an external LO source
by precision 90° phase-shifters. The demodulated I/Q
signals are single-pole low-pass filtered on-chip with a
–3dB bandwidth of 490MHz. The differential outputs of the
I-channel and Q-channel are well matched in amplitude;
their phases are 90° apart.
Broadband transformers are integrated on-chip at both
the RF and LO inputs to enable single-ended RF and LO
interfaces. In the high frequency band (1.5GHz to 2.7GHz),
both RF and LO ports are internally matched to 50Ω. No
external matching components are needed. For the lower
frequency bands (800MHz to 1.5GHz), a simple network
with series and/or shunt capacitors can be used as the
impedance matching network.
RF Input Port
Figure 4 shows the demodulator’s RF input which consists of an integrated transformer and high linearity
transconductance amplifiers. The primary side of the
transformer is connected to the RF input pin. The secondary side of the transformer is connected to the differential
inputs of the transconductance amplifiers. Under no circumstances should an external DC voltage be applied to
the RF input pin. DC current flowing into the primary side
of the transformer may cause damage to the integrated
transformer. A series blocking capacitor should be used
to AC-couple the RF input port to the RF signal source.
desired frequency as illustrated in Figure 5. For lower frequency band operation, the external matching component
C11 can serve as a series DC blocking capacitor.
RF
INPUT
EXTERNAL
MATCHING
NETWORK FOR
LOW BAND AND
MID BAND
TO I-MIXER
C11
2
RF
C10
TO Q-MIXER
3
5575 F04
Figure 4. RF Input Interface
0
RF PORT RETURN LOSS (dB)
The LT5575 is a direct I/Q demodulator targeting high
linearity receiver applications, such as RFID readers and
wireless infrastructure. It consists of RF transconductance
amplifiers, I/Q mixers, a quadrature LO phase shifter, and
bias circuitry.
C11 = 5.6pF;
C10 = 4.7pF
–5
C11 = 3.9pF;
NO SHUNT CAP
–10
–15
–20
–25
NO EXTERNAL
MATCHING
–30
0.5
1.0
1.5
2.0
FREQUENCY (GHz)
2.5
3.0
5575 F05
Figure 5. RF Input Return Loss with External Matching
The RF input port is internally matched over a wide frequency range from 1.5GHz to 2.7GHz with input return loss
typically better than 10dB. No external matching network is
needed for this frequency range. When the part is operated
at lower frequencies, however, the input return loss can
be improved with the matching network shown in Figure
4. Shunt capacitor C10 and series capacitor C11 can be
selected for optimum input impedance matching at the
5575f
11
LT5575
APPLICATIONS INFORMATION
Table 1. RF Input Impedance
S11
FREQUENCY
(GHz)
INPUT
IMPEDANCE (Ω)
MAG
ANGLE (°)
0.8
8.1 +j 21.3
0.760
133.0
0.9
10.5 +j 24.9
0.715
125.4
1.0
13.8 +j 28.8
0.660
117.2
1.1
18.6 +j 32.5
0.595
108.6
1.2
25.2 +j 35.5
0.521
99.6
1.3
33.6 +j 36.8
0.441
90.3
1.4
43.1 +j 34.6
0.355
80.8
1.5
51.4 +j 28.4
0.270
71.6
1.6
55.8 +j 19.3
0.188
63
1.7
55.4 +j 10.4
0.110
56.9
1.8
51.8 +j 3.9
0.042
63
1.9
46.9 +j 0.4
0.032
172.7
2.0
42.3 +j –0.8
0.084
–173.9
2.1
38.4 +j –0.3
0.131
–178.2
2.2
35.4 +j 1
0.172
175.3
2.3
33 +j 2.9
0.207
168.4
2.4
31.5 +j 4.9
0.235
161.9
2.5
30.4 +j 7
0.258
155.4
2.6
29.9 +j 9.1
0.274
149.2
2.7
29.7 +j 11.1
0.287
143.4
LO Input Port
The demodulator’s LO input interface is shown in Figure 6. The input consists of an integrated transformer and a
precision quadrature phase shifter which generates 0° and
90° phase-shifted LO signals for the LO buffer amplifiers
driving the I/Q mixers. The primary side of the transformer
is connected to the LO input pin. The secondary side of
the transformer is connected to the differential inputs of
the LO quadrature generator. Under no circumstances
should an external DC voltage be applied to the input pin.
DC current flowing into the primary side of the transformer
may damage the transformer. A series blocking capacitor
should be used to AC-couple the LO input port to the LO
signal source.
The LO input port is internally matched over a wide frequency range from 1.5GHz to 2.7GHz with input return
loss typically better than 10dB. No external matching
network is needed for this frequency range. When the part
is operated at a lower frequency, the input return loss can
be improved with the matching network shown in Figure
6. Shunt capacitor C12 and series capacitor C13 can be
selected for optimum input impedance matching at the
desired frequency as illustrated in Figure 7. For lower
frequency operation, external matching component C13
can serve as the series DC blocking capacitor.
LO
INPUT
EXTERNAL
MATCHING
NETWORK FOR
LOW BAND AND
MID BAND
C13
11
LO QUADRATURE
GENERATOR AND
BUFFER AMPLIFIERS
10
C12
LO
5575 F06
Figure 6. LO Input Interface
0
LO PORT RETURN LOSS (dB)
The RF input impedance and S11 parameters (without
external matching components) are listed in Table 1.
C13 = 5.6pF;
C12 = 3.9pF
–5
–10
NO EXTERNAL
MATCHING
–15
C13 = 5.6pF;
NO SHUNT CAP
–20
–25
–30
0.5
1.0
1.5
2.0
FREQUENCY (GHz)
2.5
3.0
5575 F07
Figure 7. LO Input Return Loss with External Matching
5575f
12
LT5575
APPLICATIONS INFORMATION
The LO input impedance and S11 parameters (without
external matching components) are listed in Table 2.
Table 2. LO Input Impedance
S11
FREQUENCY
(GHz)
INPUT
IMPEDANCE (Ω)
MAG
ANGLE (°)
0.8
9.6 +j 23.7
0.731
127.9
0.9
13 +j 27.1
0.669
120.4
1.0
17.9 +j 30
0.592
113.2
1.1
24.1 +j 31.7
0.508
106.1
1.2
31.2 +j 31.4
0.421
99.8
1.3
37.5 +j 28.9
0.341
95.1
1.4
41.9 +j 24.6
0.272
93.4
1.5
43.4 +j 20
0.221
96.2
1.6
42.9 +j 16.4
0.189
103.5
1.7
41.2 +j 14.1
0.18
113.1
1.8
39.5 +j 13.1
0.186
120.3
1.9
37.8 +j 13.1
0.201
124.5
2.0
36.6 +j 13.6
0.217
125.6
2.1
35.6 +j 14.6
0.236
125
2.2
35.1 +j 15.7
0.25
123.1
2.3
34.9 +j 17.1
0.264
120.1
2.4
35.1 +j 18.5
0.272
116.6
2.5
35.5 +j 19.9
0.281
113
2.6
36.3 +j 21.2
0.284
109
2.7
37.2 +j 22.5
0.287
105.1
I-Channel and Q-Channel Outputs
Each of the I-channel and Q-channel outputs is internally
connected to VCC through a 65Ω resistor. The output DC
bias voltage is VCC – 1.1V. The outputs can be DC-coupled
or AC-coupled to the external loads. Each single-ended
output has an impedance of 65Ω in parallel with a 5pF
internal capacitor, forming a low-pass filter with a –3dB
corner frequency at 490MHz. The loading resistance
on each output, RLOAD (single-ended), should be larger
than 300Ω to assure full gain. The gain is reduced by
20 • log10(1 + 65Ω/RLOAD) in dB when the output port is
terminated by RLOAD. For instance, the gain is reduced
by 7.23dB when each output pin is connected to a
50Ω load (or 100Ω differentially). The output should be
taken differentially (or by using differential-to-singleended conversion) for best RF performance, including
NF and IM2.
The phase relationship between the I-channel output signal
and the Q-channel output signal is fixed. When the LO
input frequency is larger (or smaller) than the RF input
frequency, the Q-channel outputs (QOUT+, QOUT– ) lead (or
lag) the I-channel outputs (IOUT+, IOUT– ) by 90°.
When AC output coupling is used, the resulting highpass filter’s –3dB roll-off frequency is defined by the RC
constant of the blocking capacitor and RLOAD, assuming
RLOAD >> 65Ω.
VCC
5pF
65Ω
65Ω
5pF
5pF
65Ω
65Ω
5pF
IOUT+
IOUT–
QOUT+
QOUT–
16
15
14
13
5575 F08
Figure 8. I/Q Output Equivalent Circuit
5575f
13
LT5575
APPLICATIONS INFORMATION
Care should be taken when the demodulator’s outputs are
DC-coupled to the external load to make sure that the I/Q
mixers are biased properly. If the current drain from the
outputs exceeds 6mA, there can be significant degradation of the linearity performance. Each output can sink no
more than 16.8mA when the outputs are connected to an
external load with a DC voltage higher than VCC – 1.1V.
The I/Q output equivalent circuit is shown in Figure 8.
In order to achieve best IIP2 performance, it is important
to minimize high frequency coupling among the baseband
outputs, RF port and LO port. For a multilayer PCB layout
design, the metal lines of the baseband outputs should be
placed on the backside of the PCB as shown in Figures 2
and 3. Typically, output shunt capacitors C1-C4 are not
required for the application near 1900MHz. However, for
other frequency bands, these capacitors can be optimized
for best IIP2 performance. For example, when the operating frequency is 900MHz, the IIP2 can be improved to
54dBm or better when 10pF shunt capacitors are placed
at each output.
Enable Interface
A simplified schematic of the EN pin is shown in Figure 9. The enable voltage necessary to turn on the LT5575
is 2V. To disable or turn off the chip, this voltage should
be below 1V. If the EN pin is not connected, the chip is
disabled. However, it is not recommended that the pin be
left floating for normal operation.
It is important that the voltage applied to the EN pin
should never exceed VCC by more than 0.3V. Otherwise,
the supply current may be sourced through the upper
ESD protection diode connected at the EN pin. Under no
circumstances should voltage be applied to the EN pin
before the supply voltage is applied to the VCC pin. If this
occurs, damage to the IC may result.
LT5575
VCC
5
EN
60k
60k
5575 F09
Figure 9. Enable Pin Simplified Circuit
5575f
14
LT5575
PACKAGE DESCRIPTION
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)
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
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
5575f
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
LT5575
RELATED PARTS
PART NUMBER
Infrastructure
LT5514
DESCRIPTION
COMMENTS
Ultralow Distortion, IF Amplifier/ADC Driver
with Digitally Controlled Gain
LT5515
1.5GHz to 2.5GHz Direct Conversion Quadrature
Demodulator
LT5516
0.8GHz to 1.5GHz Direct Conversion Quadrature
Demodulator
LT5517
40MHz to 900MHz Quadrature Demodulator
LT5518
1.5GHz to 2.4GHz High Linearity Direct
Quadrature Modulator
LT5519
0.7GHz to 1.4GHz High Linearity Upconverting
Mixer
LT5520
1.3GHz to 2.3GHz High Linearity Upconverting
Mixer
LT5521
10MHz to 3700MHz High Linearity
Upconverting Mixer
LT5522
600MHz to 2.7GHz High Signal Level
Downconverting Mixer
LT5524
Low Power, Low Distortion ADC Driver with
Digitally Programmable Gain
LT5525
High Linearity, Low Power Downconverting
Mixer
LT5526
High Linearity, Low Power Downconverting
Mixer
LT5527
400MHz to 3.7GHz High Signal Level
Downconverting Mixer
LT5528
1.5GHz to 2.4GHz High Linearity Direct
Quadrature Modulator
LT5558
600MHz to 1100MHz High Linearity Direct
Quadrature Modulator
LT5560
Ultra-Low Power Active Mixer
LT5568
700MHz to 1050MHz High Linearity Direct
Quadrature Modulator
LT5572
1.5GHz to 2.5GHz High Linearity Direct
Quadrature Modulator
RF Power Detectors
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 Log RF Power Detector with
60dB Dynamic Range
LTC5536
Precision 600MHz to 7GHz RF Power Detector
with Fast Comparator Output
LT5537
Wide Dynamic Range Log RF/IF Detector
850MHz Bandwidth, 47dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Range
20dBm IIP3, Integrated LO Quadrature Generator
21.5dBm IIP3, Integrated LO Quadrature Generator
21dBm IIP3, Integrated LO Quadrature Generator
22.8dBm OIP3 at 2GHz, –158.2dBm/Hz Noise Floor, 50Ω Single-Ended RF and LO
Ports, 4-Channel W-CDMA ACPR = –64dBc at 2.14GHz
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
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,
–65dBm LO-RF Leakage
IIP3 = 23.5dBm and NF = 12.5dBm at 1900MHz, 4.5V to 5.25V Supply, ICC = 78mA,
Conversion Gain = 2dB
21.8dBm OIP3 at 2GHz, –159.3dBm/Hz Noise Floor, 50Ω, 0.5VDC Baseband
Interface, 4-Channel W-CDMA ACPR = –66dBc at 2.14GHz
22.4dBm OIP3 at 900MHz, –158dBm/Hz Noise Floor, 3kΩ, 2.1VDC Baseband
Interface, 3-Ch CDMA2000 ACPR = –70.4dBc at 900MHz
10mA Supply Current, 10dBm IIP3, 10dB NF, Usable as Up- or Down-Converter.
22.9dBm OIP3 at 850MHz, –160.3dBm/Hz Noise Floor, 50Ω, 0.5VDC Baseband
Interface, 3-Ch CDMA2000 ACPR = –71.4dBc at 850MHz
21.6dBm OIP3 at 2GHz, –158.6dBm/Hz Noise Floor, High-Ohmic 0.5VDC Baseband
Interface, 4-Ch W-CDMA ACPR = –67.7dBc at 2.14GHz
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 over Temperature, 38ns Response Time, Log Linear
Response
25ns Response Time, Comparator Reference Input, Latch Enable Input,
–26dBm to +12dBm Input Range
Low Frequency to 1GHz, 83dB Log Linear Dynamic Range
5575f
16 Linear Technology Corporation
LT 0107 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2007
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