LT5526EUF#PBF [Linear]
LT5526 - High Linearity, Low Power Downconverting Mixer; Package: QFN; Pins: 16; Temperature Range: -40°C to 85°C;
| 型号： | LT5526EUF#PBF |
| 厂家： | 
Linear |
| 描述： | LT5526 - High Linearity, Low Power Downconverting Mixer; Package: QFN; Pins: 16; Temperature Range: -40°C to 85°C 电信 电信集成电路 |
| 文件： | 总16页 (文件大小：226K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT5526
High Linearity, Low Power
Downconverting Mixer
U
FEATURES
DESCRIPTIO
The LT®5526 is a low power broadband mixer optimized
for high linearity applications such as point-to-point data
transmission,cableinfrastructureandwirelessinfrastruc-
ture systems. The device includes an internally matched
high speed LO amplifier driving a double-balanced active
mixer core. An integrated RF buffer amplifier provides
excellentLO-RFisolation.TheRFandIFportscanbeeasily
matched across a broad range of frequencies for use in a
wide variety of applications.
■
Operation up to 2GHz
■
Broadband RF, LO and IF Operation
■
High Input IP3: +16.5dBm at 900MHz
■
Typical Conversion Gain: 0.6dB at 900MHz
■
SSB Noise Figure: 11dB at 900MHz
■
On-Chip 50Ω LO Match
■
Integrated LO Buffer: –5dBm Drive Level
■
High LO-RF and LO-IF Isolation
Low Supply Current: 28mA Typ
■
■
Enable Function
Single 5V Supply
16-Lead QFN (4mm × 4mm) Package
The LT5526 offers a high performance alternative to
passivemixers. Unlikepassivemixerswhichhaveconver-
sion loss and require high LO drive levels, the LT5526
delivers conversion gain at significantly lower LO input
levels and is much less sensitive to LO power level
■
■
U
APPLICATIO S
■
variations.
Point-to-Point Data Communication Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
Wireless Infrastructure
■
Cable Downlink Infrastructure
High Linearity Receiver Applications
■
U
TYPICAL APPLICATIO
High Signal Level Frequency Downconversion
IF Output Power and IM3 vs
RF Input Power (Two Input Tones)
V
CC
5V DC
0
V
V
EN
BIAS
CC2
CC1
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
P
OUT
900MHz
900MHz
140MHz
+
–
+
–
RF
RF
IF
IF
LNA
VGA
ADC
T
= 25°C
= 140MHz
= 900MHz
= 760MHz
= –5dBm
A
f
f
f
IF
RF
LO
IM3
GND
P
LO
–5
RF INPUT POWER (dBm/TONE)
+
LO LO
–
LT5526
–20
–15
–10
0
5526 TA02
5526 TA01
LO INPUT
–5dBm
5526f
1
LT5526
W W U W
U
W U
ABSOLUTE MAXIMUM RATINGS
PACKAGE/ORDER INFORMATION
(Note 1)
TOP VIEW
Supply Voltage ...................................................... 5.5V
Enable Voltage ............................... –0.3V to VCC + 0.3V
LO Input Power ............................................... +10dBm
LO+ to LO– Differential DC Voltage ......................... ±1V
RF Input Power................................................ +10dBm
RF+ to RF– Differential DC Voltage ....................... ±0.7V
Operating Temperature Range ................ – 40°C to 85°C
Storage Temperature Range ................. –65°C to 125°C
Junction Temperature (TJ)................................... 125°C
ORDER PART
NUMBER
16 15 14 13
LT5526EUF
NC
+
1
2
3
4
12 GND
+
RF
11 IF
17
–
–
RF
NC
IF
10
9
GND
5
6
7
8
UF PART
MARKING
UF PACKAGE
16-LEAD (4mm × 4mm) PLASTIC QFN
5526
TJMAX = 125°C, θJA = 37°C/W
EXPOSED PAD (PIN 17) IS GND,
MUST BE SOLDERED TO PCB.
NC PINS SHOULD BE GROUNDED
Consult LTC Marketing for parts specified with wider operating temperature ranges.
DC ELECTRICAL CHARACTERISTICS
VCC = 5V, EN = 3V, TA = 25°C (Note 3), unless otherwise noted. Test circuit shown in Figure 1.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power Supply Requirements (V
Supply Voltage
)
CC
3.6
5
5.3
33
V
mA
µA
Supply Current
V
= 5V
28
CC
Shutdown Current
EN = Low
100
Enable (EN) Low = Off, High = On
EN Input High Voltage (On)
EN Input Low Voltage (Off)
Enable Pin Input Current
3
V
V
0.3
EN = 5V
EN = 0V
55
0.01
µA
µA
Turn-On Time (Note 5)
Turn-Off Time (Note 5)
3
6
µs
µs
(Notes 2, 3)
AC ELECTRICAL CHARACTERISTICS
PARAMETER
CONDITIONS
MIN
MIN
TYP
MAX
MAX
UNITS
MHz
RF Input Frequency Range (Note 4)
LO Input Frequency Range (Note 4)
IF Output Frequency Range (Note 4)
Requires RF Matching
Requires DC Blocks
Requires IF Matching
0.1 to 2000
0.1 to 2500
0.1 to 1000
MHz
MHz
VCC = 5V, EN = 3V, TA = 25°C. Test circuits shown in Figures 1 and 2. (Notes 2, 3)
PARAMETER
CONDITIONS
Z = 50Ω, External Match
TYP
15
UNITS
dB
RF Input Return Loss
LO Input Return Loss
IF Output Return Loss
LO Input Power
O
Z = 50Ω, External DC Blocks
O
15
dB
Z = 50Ω, External Match
O
15
dB
–10 to 0
dBm
5526f
2
LT5526
VCC = 5V, EN = 3V, TA = 25°C, PRF = –15dBm (–15dBm/tone for 2-tone
AC ELECTRICAL CHARACTERISTICS
IIP3 tests, ∆f = 1MHz), PLO = –5dBm, unless otherwise noted. Test circuits shown in Figures 1 and 2. (Notes 2, 3)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
RF to LO Isolation
f
f
f
= 350MHz, f = 70MHz, f = 420MHz
69
55
50
dB
dB
dB
RF
RF
RF
IF
LO
= 900MHz, f = 140MHz, f = 760MHz
IF
LO
= 1900MHz, f = 140MHz, f = 1760MHz
IF
LO
Conversion Gain
f
f
f
= 350MHz, f = 70MHz, f = 420MHz
0.6
0.6
0.4
dB
dB
dB
RF
RF
RF
IF
LO
= 900MHz, f = 140MHz, f = 760MHz
IF
LO
= 1900MHz, f = 140MHz, f = 1760MHz
IF
LO
Conversion Gain vs Temperature
Input 3rd Order Intercept
T = –40°C to 85°C
–0.013
dB/°C
A
f
f
f
= 350MHz, f = 70MHz, f = 420MHz
15.2
16.5
14.1
dBm
dBm
dBm
RF
RF
RF
IF
LO
= 900MHz, f = 140MHz, f = 760MHz
IF
LO
= 1900MHz, f = 140MHz, f = 1760MHz
IF
LO
Single Sideband Noise Figure
LO to RF Leakage
f
f
f
= 350MHz, f = 70MHz, f = 420MHz
12.7
11.0
13.7
dB
dB
dB
RF
RF
RF
IF
LO
= 900MHz, f = 140MHz, f = 760MHz
IF
LO
= 1900MHz, f = 140MHz, f = 1760MHz
IF
LO
f
f
f
= 350MHz, f = 70MHz, f = 420MHz
–65
–65
–55
dBm
dBm
dBm
RF
RF
RF
IF
LO
= 900MHz, f = 140MHz, f = 760MHz
IF
LO
= 1900MHz, f = 140MHz, f = 1760MHz
IF
LO
LO to IF Leakage
f
f
f
= 350MHz, f = 70MHz, f = 420MHz
–56
–74
–37
dBm
dBm
dBm
RF
RF
RF
IF
LO
= 900MHz, f = 140MHz, f = 760MHz
IF
LO
= 1900MHz, f = 140MHz, f = 1760MHz
IF
LO
2RF-2LO Output Spurious Product
350MHz: f = 385MHz at –15dBm, f = 420MHz
–75
–72
–48
dBc
dBc
dBc
RF
LO
(f = f ± f /2)
900MHZ: f = 830MHz at –15dBm, f = 760MHz
RF
LO
IF
RF LO
1900MHz: f = 1830MHz at –15dBm, f = 1760MHz
RF
LO
3RF-3LO Output Spurious Product
(f = f ± f /3)
350MHz: f = 396.67MHz at –15dBm, f = 420MHz
–65
–68
–56
dBc
dBc
dBc
RF
LO
900MHZ: f = 806.67MHz at –15dBm, f = 760MHz
RF
LO
IF
RF
LO
1900MHz: f = 1806.67MHz at –15dBm, f = 1760MHz
RF
LO
Input 1dB Compression
f
f
f
= 350MHz, f = 70MHz, f = 420MHz
5
5
1
dBm
dBm
dBm
RF
RF
RF
IF
LO
= 900MHz, f = 140MHz, f = 760MHz
IF
LO
= 1900MHz, f = 140MHz, f = 1760MHz
IF
LO
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 4: Operation over a wider frequency range is possible with reduced
performance. Consult the factory for information and assistance.
Note 2: The 900MHz and 1900MHz performance is measured with the test
circuit shown in Figure 1. The 350MHz performance is measured using the
test circuit in Figure 2.
Note 5: Turn-on and turn-off times correspond to a change in the output
level by 40dB.
Note 3: Specifications over the –40°C to 85°C temperature range are
assured by design, characterization and correlation with statistical process
controls.
5526f
3
LT5526
W U
900MHz Application. VCC = 5V, EN = 3V,
TYPICAL AC PERFOR A CE CHARACTERISTICS
TA = 25°C, PRF = –15dB (–15dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), fLO = fRF – 140MHz, PLO = –5dBm, IF output measured at
140MHz, unless otherwise noted. Test circuit shown in Figure 1.
Conversion Gain, IIP3 and SSB NF
vs RF Frequency (Low Side LO)
Conversion Gain, IIP3 and SSB NF
vs RF Frequency (High Side LO)
Conversion Gain, IIP3 and SSB NF
vs Temperature
20
18
16
14
12
10
8
20
18
16
14
25
20
15
10
T
f
= 25°C
= 140MHz
T
f
= 25°C
= 140MHz
f
= 140MHz
A
IF
A
IF
IF
LOW SIDE LO
IIP3
IIP3
IIP3
HIGH SIDE LO
HIGH SIDE LO
SSB NF
12 SSB NF
SSB NF
10
8
LOW SIDE LO
6
6
5
0
4
4
GAIN
LOW AND HIGH SIDE LO
2
2
GAIN
GAIN
0
0
–2
–2
–5
600
800
1000
1200
1400
600
800
1000
1200
1400
–50
10
30
50
70
90
–30 –10
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
TEMPERATURE (°C)
5526 G02
5526 G01
5526 G03
Conversion Gain and IIP3
vs LO Input Power
SSB Noise Figure
vs LO Input Power
LO-IF and LO-RF Leakage
vs LO Input Frequency
16
25
20
15
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
T
f
= 25°C
= 140MHz
f
f
= 760MHz
25°C
f
f
= 760MHz
A
IF
LO
IF
LO
IF
= 140MHz
85°C
= 140MHz
15
14
–40°C
13
12
11
10
9
IIP3
25°C
LO-IF
85°C
–40°C
LO-RF
5
0
GAIN
8
–5
–10
–8
–4
–2
0
2
–12
–6
–4
LO INPUT POWER (dBm)
0
2
700
1100
LO FREQUENCY (MHz)
–12 –10
–8
–6
–2
500
900
1300
1500
LO INPUT POWER (dBm)
5526 G05
5526 G04
5526 G06
Conversion Gain and IIP3
vs Supply Voltage
RF, LO and IF Port Return Loss
vs Frequency
IF Output Power and IM3 vs RF
Input Power (Two Input Tones)
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
0
25
20
15
10
f
f
= 760MHz
LO
IF
RF PORT
= 140MHz
–5
P
OUT
–10
–15
IF PORT
25°C
85°C
IIP3
–40°C
–20
–25
–30
5
0
f
f
= 760MHz
LO
IF
GAIN
IM3
= 140MHz
LO PORT
25°C
85°C
–40°C
–5
0
500
1000
1500
2000
–20
–15
–10
0
–5
4.4
SUPPLY VOLTAGE (V)
5.2 5.6
2.8 3.2
3.6 4.0
4.8
RF INPUT POWER (dBm/TONE)
FREQUENCY (MHz)
5526 G08
5526 G09
5526 G07
5526f
4
LT5526
W U
900MHz Application. VCC = 5V, EN = 3V,
TA = 25°C, PRF = –15dB (–15dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), fLO = fRF – 140MHz, PLO = –5dBm, IF output measured at
TYPICAL AC PERFOR A CE CHARACTERISTICS
140MHz, unless otherwise noted. Test circuit shown in Figure 1.
IFOUT, 2 × 2 and 3 × 3 Spurs
vs RF Input Power
2 × 2 and 3 × 3 Spurs
vs LO Input Power
10
0
–30
–40
–50
–60
T
= 25°C
A
IF OUT
f
f
= 760MHz
LO
IF
f
= 900MHz
RF
–10
= 140MHz
P
= –15dBm
RF
–20
–30
–40
3RF-3LO
f
= 806.67MHz
RF
–50
–60
–70
–80
2RF-2LO
= 830MHz
f
RF
2RF-2LO
= 830MHz
–70
f
RF
–80
–90
–100
–110
3RF-3LO
T
= 25°C
–90
A
f
= 806.67MHz
RF
f
f
= 760MHz
LO
IF
–100
–110
= 140MHz
–10
–12
–8
0
–20
–15
–5
0
–16
4
–4
RF INPUT POWER (dBm)
LO INPUT POWER (dBm)
5526 G10
5526 G11
1900MHz Application. VCC = 5V, EN = 3V, TA = 25°C, PRF = –15dB (–15dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz),
fLO = fRF – 140MHz, PLO = –5dBm, IF output measured at 140MHz, unless otherwise noted. Test circuit shown in Figure 1.
Conversion Gain and IIP3
vs RF Frequency
SSB Noise Figure
vs RF Frequency
IFOUT, 2 × 2 and 3 × 3 Spurs
vs RF Input Power
20
18
16
14
12
10
8
10
0
18
17
16
15
14
13
12
11
10
f
f
= f – f
IIP3
LO RF IF
IF
f
f
= f – f
25°C
85°C
–40°C
LO RF IF
IF OUT
= 1900MHz
= 140MHz
= 140MHz
IF
f
RF
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
3RF-3LO
= 1806.67MHz
f
RF
2RF-2LO
= 1830MHz
25°C
85°C
–40°C
f
RF
6
4
GAIN
2
T
= 25°C
A
f
f
= 1760MHz
LO
IF
0
= 140MHz
–2
1400
1600
1800
2000
2200
–20
–15
–10
–5 0
1800
1600
RF FREQUENCY (MHz)
1400
2000
2200
RF FREQUENCY (MHz)
RF INPUT POWER (dBm)
5526 G12
5526 G14
5526 G13
Conversion Gain and IIP3
vs LO Input Power
SSB Noise Figure
vs LO Input Power
LO-IF and LO-RF Leakage
vs LO Frequency
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
20
18
16
14
12
10
8
18
f
f
= 1760MHz
T
f
= 25°C
= 140MHz
f
f
= 1760MHz
25°C
LO
IF
A
IF
LO
= 140MHz
= 140MHz
85°C
IF
17
16
–40°C
LO-IF
15
14
13
12
11
IIP3
LO-RF
25°C
85°C
6
–40°C
4
GAIN
2
0
–2
10
–12
–8
–6 –4
–2
0
2
–10
–8
–4
–2
0
2
2300
2100
2500
–10
–12
–6
900
1700
1100 1300 1500
1900
LO INPUT POWER (dBm)
LO FREQUENCY (MHz)
LO INPUT POWER (dBm)
5526 G15
5526 G16
5526 G17
5526f
5
LT5526
W U
350MHz Application. VCC = 5V, EN = 3V,
TYPICAL AC PERFOR A CE CHARACTERISTICS
TA = 25°C, PRF = –15dB (–15dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), fLO = fRF + 70MHz, PLO = –5dBm, IF output measured at
70MHz, unless otherwise noted. Test circuit shown in Figure 2.
Conversion Gain and IIP3
vs RF Frequency
SSB Noise Figure
vs RF Frequency
IFOUT, 2 × 2 and 3 × 3 Spurs
vs RF Input Power
20
18
16
14
12
10
8
20
0
18
17
16
15
f
IF
= f + f
f
f
= f + f
25°C
85°C
–40°C
LO RF IF
LO RF IF
f
= 70MHz
= 70MHz
IF
IF OUT
= 350MHz
f
RF
IIP3
–20
–40
–60
3RF-3LO
= 396.67MHz
25°C
85°C
–40°C
14
13
f
RF
6
2RF-2LO
RF
–80
4
f
= 385MHz
12
11
10
T
= 25°C
2
A
–100
GAIN
f
f
= 420MHz
LO
IF
0
= 70MHz
–120
–2
–15
–10
0
–20
–5
320
340
RF FREQUENCY (MHz)
380
300
400
200 250
300
350
400
450
500
360
RF FREQUENCY (MHz)
RF INPUT POWER (dBm)
5526 G20
5526 G19
5526 G18
Conversion Gain and IIP3
vs LO Input Power
SSB Noise Figure
vs LO Input Power
LO-IF and LO-RF Leakage
vs LO Frequency
20
19
18
17
16
15
14
13
12
11
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
20
18
16
14
12
10
8
f
f
= 420MHz
f
f
= 420MHz
25°C
T
f
= 25°C
= 70MHz
LO
IF
LO
IF
A
IF
= 70MHz
= 70MHz
85°C
–40°C
LO-IF
IIP3
25°C
LO-RF
85°C
6
–40°C
4
GAIN
2
0
–2
2
–12
–8
–6 –4
–2
2
–12
–8
LO INPUT POWER (dBm)
–6 –4
–2
0
0
500
450
550
–10
–10
150
350
200 250 300
400
LO INPUT POWER (dBm)
LO FREQUENCY (MHz)
5526 G21
5526 G22
5526 G23
W U
Test circuit shown in Figure 1.
TYPICAL DC PERFOR A CE CHARACTERISTICS
Supply Current vs Supply Voltage
Shutdown Current vs Supply Voltage
32
30
28
26
24
22
20
18
16
14
12
10
8
25°C
85°C
–40°C
6
4
25°C
85°C
–40°C
2
0
14
4.4
SUPPLY VOLTAGE (V)
5.2 5.6
2.8 3.2 3.6 4.0
4.8
2.8 3.2 3.6 4.0
SUPPLY VOLTAGE (V)
5.6
4.4 4.8 5.2
5526 G25
5526 G24
5526f
6
LT5526
U
U
U
PI FU CTIO S
NC (Pins 1, 4, 8, 13, 16): Not Connected Internally. These
pinsshouldbegroundedonthecircuitboardforimproved
LO-to-RF and LO-to-IF isolation.
RF+, RF– (Pins 2, 3): Differential Inputs for the RF Signal.
These pins must be driven with a differential signal. Each
pin must also be connected to a DC ground capable of
sinking 7.5mA (15mA total). This DC bias return can be
accomplished through the center-tap of a balun or with
shuntinductors.Animpedancetransformationisrequired
to match the RF input to 50Ω (or 75Ω).
GND (Pins 9, 12): Ground. These pins are internally
connected to the Exposed Pad for better isolation. They
should be connected to ground on the circuit board,
though they are not intended to replace the primary
grounding through the Exposed Pad of the package.
IF– and IF+ (Pins 10, 11): Differential Outputs for the IF
Signal. An impedance transformation may be required to
match the outputs. These pins must be connected to VCC
through impedance matching inductors, RF chokes or a
transformer center-tap.
EN (Pin 5): Enable Pin. When the input voltage is higher
than 3V, the mixer circuits supplied through Pins 6, 7, 10
and 11 are enabled. When the input voltage is less than
0.3V, all circuits are disabled. Typical enable pin input
current is 55µA for EN = 5V and 0.01µA when EN = 0V.
LO–, LO+ (Pins 14, 15): Differential Inputs for the Local
Oscillator Signal. The LO input is internally matched to
50Ω; however, external DC blocking capacitors are re-
quiredbecausethesepinsareinternallybiasedtoapproxi-
mately 1.7V DC. Either LO input can be driven with a
single-ended source while connecting the unused input to
ground through a DC blocking capacitor.
V
CC1 (Pin 6): Power Supply Pin for the LO Buffer Circuits.
Typical current consumption is 11mA. This pin should be
externally connected to the other VCC pins and decoupled
with 100pF and 0.01µF capacitors.
Exposed Pad (Pin 17): Circuit Ground Return for the
EntireIC.Thismustbesolderedtotheprintedcircuitboard
ground plane.
VCC2 (Pin 7): Power Supply Pin for the Bias Circuits.
Typical current consumption is 2.5mA. This pin should be
externally connected to the other VCC pins and decoupled
with 100pF and 0.01µF capacitors.
W
BLOCK DIAGRA
17
EXPOSED
PAD
15 14
+
–
LO
LO
HIGH
SPEED
LO BUFFER
GND
12
LINEAR
AMPLIFIER
+
+
–
IF
RF
2
3
11
–
IF
RF
10
GND
DOUBLE-
BALANCED
MIXER
9
BIAS
EN
V
CC2
V
CC1
5
7
6
5526 BD
5526f
7
LT5526
TEST CIRCUITS
C6
C5
RF
GND
ER = 4.4
0.018"
0.062"
LO
IN
760MHz
DC
0.018"
GND
16
15 14
13
NC
+
–
17 NC LO LO
NC
1
2
12
11
10
9
L3
T2
T1
GND
TL1
2
6
3
4
1
2
3
5
4
RF
IN
900MHz
+
+
C4
RF
IF
C3
L2
LT5526
C1
TL2
–
3
4
IF
OUT
140MHz
1
IF
–
RF
NC
GND
EN
V
V
NC
CC1 CC2
1900MHz INPUT MATCHING:
C1: 1.5pF
T1: LDB311G9010C-440
5
6
7
8
EN
V
CC
5526 F01
C2
C8
REF DES
VALUE
SIZE
0402
0402
0402
0402
0603
PART NUMBER
REF DES
L2, L3
T1
VALUE
150nH
1:1
SIZE
1608
1206
PART NUMBER
C1
2.7pF
0.01µF
1.2pF
100pF
1µF
AVX 04025A2R7CAT
AVX 04023C103JAT
AVX 04025A1R2BAT
AVX 04025A101JAT
Toko LL1608-FSR15J
Murata LDB31900M05C-417
M/A-COM ETC4-1-2
C2
C3
T2
4:1
SM-22
L = 1.25mm
C4, C5, C6
C8
TL1, TL2
Z = 80
O
Taiyo Yuden LMK107BJ105MA
Figure 1. Test Schematic for 900MHz Application. For 1900MHz or Other Applications,
Component Values Are as Indicated in Figure 1 and in Applications Section
C6
C5
RF
GND
ER = 4.4
0.018"
0.062"
LO
IN
420MHz
DC
0.018"
C4
GND
16
15 14
13
NC
+
–
17 NC LO LO
NC
1
2
12
11
10
9
L1
L3
T2
GND
C7
L4
RF
+
1
2
3
5
4
IN
+
RF
IF
350MHz
C3
L2
LT5526
L5
–
3
4
IF
OUT
70MHz
IF
–
RF
C9
NC
GND
EN
V
V
NC
CC1 CC2
5
6
7
8
EN
V
CC
5526 F02
C2
C8
REF DES
C2
VALUE
0.01pF
3.9pF
100pF
1µF
SIZE
PART NUMBER
REF DES
L1, L4
L2, L3
L5
VALUE
15nH
270nH
100nH
4:1
SIZE
1005
1608
1005
PART NUMBER
0402
0402
0402
0603
0402
AVX 04023C103JAT
AVX 04025A3R9BAT
AVX 04025A101JAT
Toko LL1005-FH15NJ
Toko LL1608-FSR27J
Toko LL1005-FHR10J
M/A-COM ETC4-1-2
C3
C4, C5, C6
C8
Taiyo Yuden LMK107BJ105MA
AVX 04025A100JAT
T2
SM-22
C7, C9
10pF
Figure 2. Test Schematic for 350MHz Applications
5526f
8
LT5526
W U U
APPLICATIO S I FOR ATIO
U
The LT5526 consists of a double-balanced mixer, RF
buffer amplifier, high speed limiting LO buffer and
bias/enable circuits. The IC has been optimized for
downconverterapplicationswithRFinputsignalsto2GHz
and LO signals to 2.5GHz. With proper matching, the IF
output can be tuned for operation at frequencies from
0.1MHz to 1GHz. Operation over a wider input frequency
range is possible, though with reduced performance.
A lowpass impedance matching network is used to trans-
form the differential input impedance at Pins 2 and 3 to the
optimum value for the balun output, as illustrated in
Figures 3 and 4. To assist in matching, Table 1 lists the
differential input impedance and reflection coefficient at
Pins 2 and 3 for several RF frequencies. The following
example demonstrates how to design a lowpass imped-
ance transformation network for the RF input.
The RF, LO and IF ports are all differential, though the LO
port is internally matched for single-ended drive (with
external DC blocking capacitors). The LT5526 is charac-
terizedandproductiontestedusingsingle-endedLOdrive.
Low side or high side LO injection can be used.
From Table 1, the differential input impedance at 900MHz
is: RRF + jXRF = 31.3 + j8.41Ω. The 8.41Ω reactance is
divided into two halves, with one half on each side of the
31.3Ω internal load resistor, as shown in Figure 4. The
matching network consists of additional external series
inductanceandacapacitor(C1)inparallelwiththedesired
source impedance (50Ω in this example). The external
capacitance and inductance are calculated as follows:
RF Input Port
Figure 3 shows a simplified schematic of the internal RF
input circuit and example external impedance matching
components for a 900MHz application. Each RF input pin
requires a low resistance DC return to ground capable of
handling 7.5mA. The DC ground can be realized using the
center-tap of an input transformer (T1), as shown, or
through matching inductors or bias chokes connected
from Pins 2 and 3 to ground.
n = RS/RRF = 50/31.3 = 1.597
Q = √(n – 1) = 0.773
XC = RS/Q = 64.7Ω
C1 = 1/(ω • XC) = 2.74pF
XL = RRF • Q = 24.2Ω
XEXT = XL – XRF = 15.8Ω
LEXT = XEXT/ω = 2.79nH
TL1
Z
= 80Ω
0
7.5mA
LT5526
LNG = 1.25mm
+
RF
RF
2
3
RF
IN
T1
1:1
900MHz
2
1
6
3
4
C1
2.7pF
TL2
= 80Ω
Z
0
LNG = 1.25mm
–
V
7.5mA
BIAS
T1: LDB31900M05C-417
5526 F03
Figure 3. RF Input with External Matching
for 900MHz Application
5526f
9
LT5526
W U U
U
APPLICATIO S I FOR ATIO
The external inductance is split in half (1.4nH), with each
half connected between the pin and C1 as shown in
Figure 4. The inductance may be realized with short, high
impedance printed transmission lines, as in Figure 3,
which provides a compact board layout and reduced
component count. A 1:1 transformer (T1 in Figure 3)
converts the 50Ω differential impedance to a 50Ω single-
ended input.
RF
IN
LT5526
L1
C7
L4
50Ω
1/2 X
1/2 X
RF
RF
+
–
RF
RF
2
3
R
RF
L5
C9
5526 F05
Figure 5. Schematic of Lumped Element Input Balun
LT5526
1/2 X
1/2 X
EXT
EXT
RF
RF
+
RF
RF
2
3
RS •RRF
L1= L4 =
C7 = C9 =
R
S
C1
R
RF
ω
50Ω
1/2 X
1/2 X
–
1
ω RS •RRF
5526 F04
Figure 4. RF Input Impedance Matching Topology
Table 1. RF Input Differential Impedance
Where RS is the source resistance (50Ω) and RRF is the
mixer input resistance from Table 1.
The computed values are only approximate, as they don’t
factor in the effects of XRF or the parasitics of the external
components. Actual component values for several fre-
quencies are listed in Table 2, and measured return loss
vs. frequency is plotted for each example in Figure 6.
FREQUENCY
(MHz)
INPUT
IMPEDANCE
REFLECTION COEFFICIENT
MAG
0.282
0.280
0.278
0.282
0.280
0.268
0.251
0.237
0.269
ANGLE
70
140
240
360
450
750
900
1500
1900
28.0 + j1.34
28.2 + j2.46
28.4 + j3.30
28.4 + j4.75
28.6 + j5.42
29.9 + j7.39
31.3 + j8.41
38.3 + j17.9
42.5 + j24.6
176
172
169
164
0
–5
162
155
150
112
–10
–15
–20
–25
92.2
An alternative method of driving the RF input is to use a
lumped-element balun configuration, as shown in Fig-
ure 5. This type of network may provide a more cost-
effective solution for narrow band applications (fractional
bandwidths < 30%). The actual balun is composed of
components C7, C9, L1 and L4, and their values may be
estimated as follows:
100
500
700
900
1100 1300
300
FREQUENCY (MHz)
5526 F06
Figure 6. Input Return Loss with Lumped Element Baluns
Using Values from Table 2
5526f
10
LT5526
W U U
APPLICATIO S I FOR ATIO
U
External 100pF DC blocking capacitors provide a broad-
band match from about 110MHz to 2.7GHz, as shown in
the plot of return loss vs frequency in Figure 8. The LO
input match can be improved at lower frequencies by
increasing the values of C5 and C6.
The purpose of L5 is to provide a DC return path for Pin 3.
(Another possible placement for L5 would be across Pins
2 and 3, thus using L1 as part of the DC return path.) The
inductance and resonant frequency of L5 should be large
enoughthattheydon’tsignificantlyaffecttheinputimped-
ance and performance of the balun. Either multilayer or
wire-wound inductors may be used.
0
–5
The impact of L5 on input matching can be reduced by
adding a capacitor in parallel with it. In this case, the
capacitor value should be the same as C7 and C9, while L5
should have the same value as L1 and L4.
–10
–15
Table 2. Component Values for Lumped Balun on RF Input
–20
–25
–30
FREQUENCY
(MHz)
BANDWIDTH
(MHz)
L (nH)
27
C (pF)
18
L5 (nH)
100
100
47
240
380
680
900
1100
100
130
215
230
230
0
500
1000
1500
2000
2500
15
10
FREQUENCY (MHz)
6.8
4.7
3.9
2.7
5526 F08
6.8
18
Figure 8. Typical LO Input Return Loss
with 100pF DC Blocking Capacitors
3.9
15
LO Input Port
Table 3. Single-Ended LO Input Impedance
FREQUENCY
(MHz)
INPUT
IMPEDANCE
REFLECTION COEFFICIENT
The LO buffer amplifier consists of high speed limiting
differential amplifiers designed to drive the mixer core for
highlinearity.TheLO+andLO–pinsaredesignedforsingle-
ended drive, though differential drive can be used if de-
sired. TheLOinputisinternallymatchedto50Ω;however,
external DC blocking capacitors are required because the
LO pins are internally biased to approximately 1.7V DC. A
simplified schematic for the LO input is shown in Figure 7.
MAG
0.158
0.128
0.122
0.127
0.135
0.144
0.154
0.160
ANGLE
–35.8
–31.5
–26.6
–26.1
–28.8
–34.0
–40.3
–46.2
400
600
63.4 – j12.0
61.6 – j8.38
61.8 – j6.86
62.4 – j7.09
62.8 – j8.32
62.6 – j10.3
61.9 – j12.6
60.5 – j14.4
800
1000
1200
1400
1600
1800
C5
100pF
LT5526
–
LO
14
IF Output Port
50Ω
V
CC
C6
100pF
A simplified schematic of the IF output circuit is shown in
Figure 9. The output pins, IF+ and IF–, are internally
connected to the collectors of the mixer switching transis-
tors.Bothpinsmustbebiasedatthesupplyvoltage,which
can be applied through the center-tap of a transformer or
+
LO
LO
IN
15
50Ω
5526 F07
Figure 7. LO Input Schematic
5526f
11
LT5526
W U U
U
APPLICATIO S I FOR ATIO
throughimpedance-matchinginductors.EachIFpindraws
about 7.5mA of supply current (15mA total). For optimum
single-endedperformance,thesedifferentialoutputsmust
be combined externally through an IF transformer or
balun.
network, along with the impedance values listed in Table
4. As an example, at an IF frequency of 140MHz and RL =
200Ω (using a 4:1 transformer for T2),
n = RIF/RL = 574/200 = 2.87
Q = √(n – 1) = 1.368
XC = RIF/Q = 420Ω
C = 1/(ω • XC) = 2.71pF
C3 = C – CIF = 2.01pF
XL = RL • Q = 274Ω
LT5526
IF
OUT
L3
T2
4:1
+
IF
IF
11
10
575Ω
C3
V
CC
L2
0.7pF
–
L2 = L3 = XL/2ω = 156nH
V
CC
Table 4. IF Differential Impedance (Parallel Equivalent)
5526 F09
FREQUENCY
(MHz)
OUTPUT
IMPEDANCE
REFLECTION COEFFICIENT
Figure 9. IF Output with External Matching
MAG
0.840
0.840
0.840
0.838
0.834
0.831
0.829
0.822
0.814
ANGLE
70
575|| – j3.39k
574|| – j1.67k
572|| – j977
561|| – j519
537|| – j309
525|| – j267
509|| – j229
474|| – j181
435|| – j147
–1.8
An equivalent small-signal model for the output is shown
in Figure 10. The output impedance can be modeled as a
575Ω resistor in parallel with a 0.7pF capacitor. For most
applications, the bond-wire inductance (0.7nH per side)
can be ignored.
140
–3.5
240
–5.9
450
–11.1
–18.6
–21.3
–24.8
–31.3
–38.0
750
860
1000
1250
1500
LT5526
0.7nH
0.7nH
L3
+
–
IF
IF
11
10
C
R
R
L
200Ω
IF
IF
C3
L2
0.7pF
574Ω
Low Cost Output Match
For low cost applications in which the required fractional
bandwidth of the IF output is less than 25%, it may be
possible to replace the output transformer with a lumped-
element network similar to that discussed earlier for the
RF input. This circuit is shown in Figure 11, where L11,
L12, C11 and C12 form a narrowband bridge balun. These
element values are selected to realize a 180° phase shift at
thedesiredIFfrequencyandcanbeestimatedbyusingthe
equations below. In this case, RIF is the mixer output
resistance and RL is the load resistance (50Ω).
5526 F10
Figure 10. IF Output Small-Signal Model
The external components, C3, L2 and L3 form an imped-
ance transformation network to match the mixer output
impedance to the input impedance of transformer T2. The
values for these components can be estimated using the
same equations that were used for the input matching
5526f
12
LT5526
W U U
APPLICATIO S I FOR ATIO
U
0
RIF •RL
L11= L12 =
C11= C12 =
ω
1
ω RIF •RL
–5
–10
–15
–20
–25
I
nductors L13 and L14 provide a DC path between VCC
and the IF+ pin. Only one of these inductors is required.
Low cost multilayer chip inductors are adequate for L11,
L12 and L13. If L14 is used instead of L13, a larger value
is usually required, which may require the use of a wire-
wound inductor. Capacitor C13 is a DC block which can
also be used to adjust the impedance match. Capacitor
C14 is a bypass capacitor.
100
200
250
300
350
400
150
FREQUENCY (MHz)
5526 F12
Figure 12. Typical Return Loss Performance with
a 240MHz Narrowband Bridge IF Balun (Swept IF)
20
T
= 25°C
C12
A
L11
C11
+
–
IF
IF
f
f
= 1900MHz
RF
C13
C14
= f – f
LO
LO RF IF
= –5dBm
15
10
5
P
IF
L14
OPT
OUT
50Ω
IIP3
L13
OPT
L12
V
CC
GAIN
5526 F11
0
Figure 11. Narrowband Bridge IF Balun
–5
190
210
230
250
270
290
Typical return loss of the IF output port is plotted versus
frequencyinFigure12fora240MHzbalundesign. Forthis
example, L11 = L12 = 100nH, C11 = C12 = 3.9pF, L14 =
560nH and C13 = 100pF. Performance versus IF output
frequency is shown in Figure 13 in the case of a 1900MHz
RF input. These results show that the usable IF bandwidth
isgreaterthan60MHz, assumingtighttolerancematching
components. Contact the factory for applications assis-
tance with this circuit.
IF FREQUENCY (MHz)
5526 F13
Figure 13. Typical Gain and IIP3 Performance with
a 240MHz Narrowband Bridge IF Balun (Swept IF)
5526f
13
LT5526
U
TYPICAL APPLICATIO S
Evaluation Board Layouts
Top Layer Silkscreen
Top Layer Metal
5526f
14
LT5526
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
2.90 ± 0.05
2.15 ± 0.05
(4 SIDES)
PACKAGE OUTLINE
0.30 ±0.05
0.65 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
BOTTOM VIEW—EXPOSED PAD
0.75 ± 0.05
R = 0.115
TYP
0.55 ± 0.20
4.00 ± 0.10
(4 SIDES)
15
16
PIN 1
TOP MARK
(NOTE 6)
1
2
2.15 ± 0.10
(4-SIDES)
(UF) QFN 1103
0.30 ± 0.05
0.65 BSC
0.200 REF
0.00 – 0.05
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
5526f
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 represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
15
LT5526
RELATED PARTS
PART NUMBER DESCRIPTION
COMMENTS
Infrastructure
LT5511
LT5512
LT5514
High Linearity Upconverting Mixer
RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer
DC to 3GHz, 21dBm IIP3, Integrated LO Buffer
DC-3GHz High Signal Level Downconverting Mixer
Ultralow Distortion, IF Amplifier/ADC Driver with Digitally
Controlled Gain
850MHz Bandwidth, 47dBm OIP3 at 100MHz, 10.5dB to 33dB Gain
Control Range
LT5515
LT5516
LT5517
LT5519
1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator
0.8GHz to 1.5GHz Direct Conversion Quadrature Demodulator
40MHz to 900MHz Quadrature Demodulator
20dBm IIP3, Integrated LO Quadrature Generator
21.5dBm IIP3, Integrated LO Quadrature Generator
21dBm IIP3, Integrated LO Quadrature Generator
0.7GHz to 1.4GHz High Linearity Upconverting Mixer
17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50Ω
Matching, Single-Ended LO and RF Ports Operation
LT5520
LT5521
LT5522
1.3GHz to 2.3GHz High Linearity Upconverting Mixer
3.7GHz Very High Linearity Mixer
15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with 50Ω
Matching, Single-Ended LO and RF Ports Operation
24.2dBm IIP3 at 1.95GHz, 12.5dB SSBNF, –42dBm LO Leakage,
Supply Voltage = 3.15V to 5.25V
600MHz to 2.7GHz High Signal Level Downconverting Mixer
4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB,
50Ω Single-Ended RF and LO Ports
RF Power Detectors
LT5504
800MHz to 2.7GHz RF Measuring Receiver
80dB Dynamic Range, Temperature Compensated,
2.7V to 5.25V Supply
LTC®5505
LTC5507
LTC5508
LTC5509
LTC5530
LTC5531
LTC5532
LT5534
RF Power Detectors with >40dB Dynamic Range
100kHz to 1000MHz RF Power Detector
300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply
100kHz to 1GHz, Temperature Compensated, 2.7V to 6V Supply
44dB Dynamic Range, Temperature Compensated, SC70 Package
36dB Dynamic Range, Low Power Consumption, SC70 Package
300MHz to 7GHz RF Power Detector
300MHz to 3GHz RF Power Detector
300MHz to 7GHz Precision RF Power Detector
300MHz to 7GHz Precision RF Power Detector
300MHz to 7GHz Precision RF Power Detector
50MHz to 3GHz RF Power Detector with 60dB Dynamic Range
Precision V
Precision V
Precision V
Offset Control, Shutdown, Adjustable Gain
Offset Control, Shutdown, Adjustable Offset
Offset Control, Adjustable Gain and Offset
OUT
OUT
OUT
±1dB Output Variation over Temperature, 38ns Response Time
Low Voltage RF Building Blocks
LT5500
LT5502
1.8GHz to 2.7GHz Receiver Front End
1.8V to 5.25V Supply, Dual-Gain LNA, Mixer, LO Buffer
400MHz Quadrature IF Demodulator with RSSI
1.8V to 5.25V Supply, 70MHz to 400MHz IF, 84dB Limiting Gain,
90dB RSSI Range
LT5503
LT5506
LT5546
1.2GHz to 2.7GHz Direct IQ Modulator and
Upconverting Mixer
1.8V to 5.25V Supply, Four-Step RF Power Control,
120MHz Modulation Bandwidth
500MHz Quadrature IF Demodulator with VGA
1.8V to 5.25V Supply, 40MHz to 500MHz IF, –4dB to 57dB
Linear Power Gain, 8.8MHz Baseband Bandwidth
500MHz Ouadrature IF Demodulator with
VGA and 17MHz Baseband Bandwidth
17MHz Baseband Bandwidth, 40MHz to 500MHz IF, 1.8V to 5.25V
Supply, –7dB to 56dB Linear Power Gain
Wide Bandwidth ADCs
LT1749
LT1750
12-Bit, 80Msps
500MHz BW S/H, 71.8dB SNR, 87dB SFDR
14-Bit, 80Msps
500MHz BW S/H, 75.5dB SNR, 90dB SFDR, 2.25V or 1.35V
Input Ranges
P-P
P-P
5526f
LT/TP 0704 1K • PRINTED IN THE USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
©LINEAR TECHNOLOGY CORPORATION 2004
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