LINER LTC5544

LTC5544
4GHz to 6GHz
High Dynamic Range
Downconverting Mixer
Description
Features
Conversion Gain: 7.4dB at 5250MHz
n IIP3: 25.9dBm at 5250MHz
n Noise Figure: 11.3dB at 5250MHz
n High Input P1dB
n IF Bandwidth Up to 1GHz
n 640mW Power Consumption
n Shutdown Pin
n 50Ω Single-Ended RF and LO Inputs
n+2dBm LO Drive Level
n High LO-RF and LO-IF Isolation
n–40°C to 105°C Operation (T )
C
n Small Solution Size
n16-Lead (4mm × 4mm) QFN package
The LTC®5544 is part of a family of high dynamic range, high
gain passive downconverting mixers covering the 600MHz
to 6GHz frequency range. The LTC5544 is optimized for
4GHz to 6GHz RF applications. The LO frequency must
fall within the 4.2GHz to 5.8GHz range for optimum
performance. A typical application is a WiMAX receiver
with a 5.15GHz to 5.35GHz RF input and low side LO.
n
The LTC5544 is designed for 3.3V operation, however; the
IF amplifier can be powered with 5V for the higher P1dB.
The LTC5544’s high level of integration minimizes the total
solution cost, board space and system-level variation,
while providing the highest dynamic range for demanding
receiver applications.
Applications
High Dynamic Range Downconverting Mixer Family
5GHz WiMAX/WLAN Receiver
n4.9GHz Public Safety Bands
n4.9GHz to 6GHz Military Communications
n Point-to-Point Broadband Communications
n Radar Systems
n
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
PART#
RF RANGE
LO RANGE
LTC5540
600MHz to 1.3GHz
700MHz to 1.2GHz
LTC5541
1.3GHz to 2.3GHz
1.4GHz to 2.0GHz
LTC5542
1.6GHz to 2.7GHz
1.7GHz to 2.5GHz
LTC5543
2.3GHz to 4GHz
2.4GHz to 3.6GHz
LTC5544
4GHz to 6GHz
4.2GHz to 5.8GHz
Typical Application
Wideband Conversion Gain, IIP3
and NF vs IF Output Frequency
Wideband Receiver
240MHz
SAW
1nF
22pF
1µF
RF
5150MHz
TO
5350MHz
LTC5544
1.2pF
SYNTH
LO
2.2nH
VCC1
VCC 3.3V
LO
5010MHz
fLO = 5010MHz
7.9 PLO = 2dBm
RF = 5250 ±35MHz
7.7
TEST CIRCUIT IN FIGURE 1
7.5
7.3
6.9
6.5
205
VCC2
25
23
21
19
GC
17
7.1
6.7
BIAS
SHDN
27
IIP3
8.1
RF
SHDN
(0V/3.3V)
29
8.3
IF –
IF
LNA
8.5
ADC
15
IIP3 (dBm), SSB NF (dB)
IF+
IMAGE
BPF 0.6pF
IF
AMP
1nF
150nH
150nH
LTC2208
GC (dB)
VCCIF
3.3V or 5V
LTC6416
13
NF
11
215 225 235 245 255 265
IF OUTPUT FREQUENCY (MHz)
9
275
5544 TA01b
1µF
22pF
5544 TA01a
5544f
1
LTC5544
Absolute Maximum Ratings
Pin Configuration
(Note 1)
Mixer Supply Voltage (VCC1, VCC2)............................4.0V
IF Supply Voltage (IF+, IF –).......................................5.5V
Shutdown Voltage (SHDN).................–0.3V to VCC +0.3V
IF Bias Adjust Voltage (IFBIAS)..........–0.3V to VCC +0.3V
LO Bias Adjust Voltage (LOBIAS).......–0.3V to VCC +0.3V
LO Input Power (4GHz to 6GHz)............................+9dBm
LO Input DC Voltage................................................ ±0.1V
RF Input Power (4GHz to 6GHz).......................... +15dBm
RF Input DC Voltage................................................ ±0.1V
TEMP Diode Continuous DC Input Current..............10mA
TEMP Diode Input Voltage......................................... ±1V
Operating Temperature Range (TC)......... –40°C to 105°C
Storage Temperature Range................... –65°C to 150°C
Junction Temperature (TJ)..................................... 150°C
IFGND
IF–
IF+
IFBIAS
TOP VIEW
16 15 14 13
GND 1
12 TEMP
RF 2
11 GND
17
GND
CT 3
10 LO
SHDN 4
6
7
8
VCC1
LOBIAS
VCC2
GND
9
5
GND
UF PACKAGE
16-LEAD (4mm × 4mm) PLASTIC QFN
TJMAX = 150°C, θJC = 8°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
CASE TEMPERATURE RANGE
LTC5544IUF#PBF
LTC5544IUF#TRPBF
5544
16-Lead (4mm x 4mm) Plastic QFN
–40°C to 105°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard 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/
AC Electrical Characteristics
VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm,
unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3)
PARAMETER
CONDITIONS
MIN
LO Input Frequency Range
RF Input Frequency Range
Low Side LO
High Side LO
IF Output Frequency Range
Requires External Matching
RF Input Return Loss
ZO = 50Ω, 4000MHz to 6000MHz
LO Input Return Loss
ZO = 50Ω, 4200MHz to 5800MHz
IF Output Impedance
Differential at 240MHz
LO Input Power
fLO = 4200MHz to 5800MHz
TYP
MAX
4200 to 5800
MHz
4200 to 6000
4000 to 5800
MHz
MHz
5 to 1000
MHz
>12
–1
UNITS
dB
>12
dB
332Ω || 1.7pF
R||C
2
5
dBm
LO to RF Leakage
fLO = 4200MHz to 5800MHz, Requires C2
<–30
dBm
LO to IF Leakage
fLO = 4200MHz to 5800MHz
<–21
dBm
RF to LO Isolation
fRF = 4000MHz to 6000MHz
>38
dB
RF to IF Isolation
fRF = 4000MHz to 6000MHz
>29
dB
5544f
2
LTC5544
AC Electrical Characteristics
VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm,
PRF = –3dBm (–3dBm/tone for 2-tone tests),unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3)
Low Side LO Downmixer Application: RF = 4200MHz to 6000MHz, IF = 240MHz, fLO = fRF – fIF
PARAMETER
CONDITIONS
Conversion Gain
RF = 4900MHz
RF = 5250MHz
RF = 5800MHz
MIN
TYP
6.0
7.9
7.4
6.4
MAX
UNITS
Conversion Gain Flatness
RF = 5250MHz ±30MHz, LO = 5010MHz, IF = 240 ±30MHz
±0.15
dB
Conversion Gain vs Temperature
TC = –40°C to 105°C, RF = 5250MHz
–0.007
dB/°C
2-Tone Input 3rd Order Intercept
(∆f = 2MHz)
RF = 4900MHz
RF = 5250MHz
RF = 5800MHz
25.4
25.9
25.8
dBm
2-Tone Input 2nd Order Intercept
(∆f = 241MHz, fIM2 = fRF1 – fRF2)
fRF1 = 5371MHz, fRF2 = 5130MHz,
fLO = 5010MHz
43.2
dBm
SSB Noise Figure
RF = 4900MHz
RF = 5250MHz
RF = 5800MHz
10.3
11.3
12.8
dB
SSB Noise Figure Under Blocking
fRF = 5250MHz, fLO = 5010MHz,
fBLOCK = 4910MHz, PBLOCK = 5dBm
16.9
dB
2RF – 2LO Output Spurious Product
(fRF = fLO + fIF /2)
fRF = 5130MHz at –10dBm, fLO = 5010MHz, fIF = 240MHz
–58.3
dBc
3RF – 3LO Output Spurious Product
(fRF = fLO + fIF /3)
fRF = 5090MHz at –10dBm, fLO = 5010MHz, fIF = 240MHz
–77
dBc
Input 1dB Compression
RF = 5250MHz, VCCIF = 3.3V
RF = 5250MHz, VCCIF = 5V
11.4
14.6
dBm
dB
High Side LO Downmixer Application: RF = 4000MHz to 5800MHz, IF = 240MHz, fLO = fRF + fIF
PARAMETER
CONDITIONS
Conversion Gain
RF = 4500MHz
RF = 4900MHz
RF = 5250MHz
MIN
TYP
8.0
7.7
7.3
MAX
UNITS
dB
Conversion Gain Flatness
RF = 4900MHz ±30MHz, LO = 5356MHz, IF = 456 ±30MHz
±0.15
dB
Conversion Gain vs Temperature
TC = –40°C to 105°C, RF = 4900MHz
–0.005
dB/°C
2-Tone Input 3rd Order Intercept
(∆f = 2MHz)
RF = 4500MHz
RF = 4900MHz
RF = 5250MHz
24.2
25.1
24.0
dBm
2-Tone Input 2nd Order Intercept
(∆f = 241MHz, fIM2 = fRF2 – fRF1)
fRF1 = 4779MHz, fRF2 = 5020MHz,
fLO = 5140MHz
39.8
dBm
SSB Noise Figure
RF = 4500MHz
RF = 4900MHz
RF = 5250MHz
10.7
11.0
11.7
dB
2LO – 2RF Output Spurious Product
(fRF = fLO – fIF/2)
fRF = 5020MHz at –10dBm, fLO = 5140MHz
fIF = 240MHz
–55
dBc
3LO – 3RF Output Spurious Product
(fRF = fLO – fIF/3)
fRF = 5060MHz at –10dBm, fLO = 5140MHz
fIF = 240MHz
–75
dBc
Input 1dB Compression
RF = 4900MHz, VCCIF = 3.3V
RF = 4900MHz, VCCIF = 5V
11.3
14.5
dBm
5544f
3
LTC5544
DC Electrical Characteristics
noted. Test circuit shown in Figure 1. (Note 2)
PARAMETER
VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, unless otherwise
CONDITIONS
MIN
TYP
MAX
UNITS
VCC Supply Voltage (Pins 5 and 7)
3.1
3.3
3.5
V
VCCIF Supply Voltage (Pins 14 and 15)
3.1
3.3
5.3
V
96
98
194
116
122
238
mA
500
µA
0.3
V
30
µA
Power Supply Requirements (VCC, VCCIF)
VCC Supply Current (Pins 5 + 7)
VCCIF Supply Current (Pins 14 + 15)
Total Supply Current (VCC + VCCIF)
Total Supply Current – Shutdown
SHDN = High
Shutdown Logic Input (SHDN) Low = On, High = Off
SHDN Input High Voltage (Off)
3.0
V
SHDN Input Low Voltage (On)
SHDN Input Current
–0.3V to VCC + 0.3V
–20
Turn On Time
0.6
µs
Turn Off Time
0.6
µs
Temperature Sensing Diode (TEMP)
DC Voltage at TJ = 25°C
IIN = 10µA
IIN = 80µA
726.1
782.5
mV
mV
Voltage Temperature Coefficient
IIN = 10µA
IIN = 80µA
–1.73
–1.53
mV/°C
mV/°C
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: The LTC5544 is guaranteed functional over the –40°C to 105°C
case temperature range.
Note 3: SSB Noise Figure measurements performed with a small-signal
noise source, bandpass filter and 6dB matching pad on RF input, 6dB
matching pad on the LO input, bandpass filter on the IF output and no
other RF signals applied.
Typical DC Performance Characteristics
VCC Supply Current vs Supply
Voltage (Mixer and LO Buffer)
VCCIF Supply Current
vs Supply Voltage (IF Amplifier)
102
TC = 105°C
96
TC = 25°C
94
TC = –40°C
3.1
3.2
3.3
3.4
3.5
VCC SUPPLY VOLTAGE (V)
TC = 105°C
TC = 85°C
115
105
TC = 25°C
95
TC = –40°C
85
3.6
5544 G01
75
3.0
3.3
3.6 3.9 4.2 4.5 4.8 5.1 5.4
VCCIF SUPPLY VOLTAGE (V)
5544 G02
Total Supply Current
vs Temperature (VCC + VCCIF)
210
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
125
TC = 85°C
98
90
3.0
220
135
100
92
SHDN = Low, Test circuit shown in Figure 1.
VCC = 3.3V, VCCIF = 5V
(DUAL SUPPLY)
200
190
VCC = VCCIF = 3.3V
(SINGLE SUPPLY)
180
170
–40 –20
0
20 40 60 80
CASE TEMPERATURE (°C)
100 120
5544 G03
5544f
4
LTC5544
Typical AC Performance Characteristics
Low Side LO
VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests, ∆f = 2MHz),
IF = 240MHz, unless otherwise noted. Test circuit shown in Figure 1.
Conversion Gain and IIP3
vs RF Frequency
Conversion Gain and IIP3
vs RF Frequency
IIP3
27
13
25
21
9
GC
7
19
23
21
7
IIP3
16
15
TC = –40°C 11
TC = 25°C
TC = 85°C
TC = 105°C 9
INPUT P1dB (dBm)
13
GC (dB)
IIP3 (dBm)
9
GC
Input P1dB vs RF Frequency
15
27
GC
7
19
14
VCCIF = 5V
13
12
11
VCCIF = 3.3V
PLO = –1dBm
PLO = 2dBm
PLO = 5dBm
10
9
4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
RF FREQUENCY (GHz)
5
17
4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
RF FREQUENCY (GHz)
5544 G07
5544 G06
SSB NF and DSB NF
vs RF Frequency
5250MHz Conversion Gain,
IIP3 and NF vs LO Power
16
28
SSB NF
GC (dB), IIP3 (dBm)
DSB NF
8
6
4
2
20
24
12
10
22
IIP3
26
TC = –40°C
TC = 25°C
TC = 85°C
TC = 105°C
0
4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
RF FREQUENCY (GHz)
5544 G08
18
16
22
20
14
NF
12
18
10
16
14
12
10
GC
8
6
–3 –2 –1
TC = –40°C 8
TC = 25°C 6
TC = 85°C
4
0 1 2 3 4 5
LO INPUT POWER (dBm)
SSB NF (dB)
SSB NF, DSB NF (dB)
14
11
5544 G05
Conversion Gain and IIP3
vs RF Frequency
21
13
VCC = VCCIF
VCC = 3.1V
VCC = 3.3V
VCC = 3.5V
5
17
4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
RF FREQUENCY (GHz)
5544 G04
23
IIP3
19
5
17
4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
RF FREQUENCY (GHz)
25
15
GC (dB)
PLO = –1dBm
PLO = 2dBm 11
PLO = 5dBm
23
GC (dB)
IIP3 (dBm)
25
15
IIP3 (dBm)
27
2
6
7
0
5544 G09
5544f
5
LTC5544
Typical AC Performance Characteristics
Low Side LO (continued)
VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests, Δf = 2MHz),
IF = 240MHz, unless otherwise noted. Test circuit shown in Figure 1.
0
RF = 5250MHz
VCCIF = 5V
VCCIF = 3.3V
22
20
18
P1dB
16
14
12
–20
–30
8
–50
–5 15 35 55 75
CASE TEMPERATURE (°C)
95
–80
–12 –9
115
5544 G10
SSB Noise Figure
vs RF Blocker Level
LO TO RF LEAKAGE (dBm)
SSB NF (dB)
PLO = –1dBm
16
15
PLO = 2dBm
14
13
12
PLO = 5dBm
11
10
–25
–20
–15
–10
–5
0
RF BLOCKER POWER (dBm)
–6
5544 G11
–20
–30
RF = 5250MHz
20
25
20
15
10
6
5544 G12
RF TO LO
40
RF TO IF
4.4
C2 = 0.4pF
C2 = 0.6pF
4.6 4.8 5.0 5.2 5.4
LO FREQUENCY (GHz)
5.6
TC = 85°C
TC = 25°C
TC = –40°C
5544 G14
45
RF = 5250MHz
15
10
5
LO TO IF
20
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
RF/LO FREQUENCY (GHz)
5544 G15
5.8
5250MHz IIP3 Histogram
25
–2
0
2
4
LO INPUT POWER (dBm)
RF/LO Isolation
30
–40
5544 G13
–4
50
C2 = OPEN
–50
4.2
5
DISTRIBUTION (%)
DISTRIBUTION (%)
3RF – 3LO
(RF = 5090MHz)
60
C2 = 1pF
30
40
35
5250MHz SSB NF Histogram
TC = 85°C
TC = 25°C
TC = –40°C
RF = 5250MHz
30
25
20
15
10
5
5
0
–70
–10
5250MHz Conversion Gain
Histogram
TC = 85°C
TC = 25°C
TC = –40°C
–60
–80
12 15
2RF – 2LO
(RF = 5130MHz)
LO to RF Leakage vs LO Frequency
RF = 5250MHz
19 LO = 5010MHz
BLOCKER = 4910MHz
18
17
–6 –3 0
3
6
9
RF INPUT POWER (dBm)
RF = 5250MHz
PRF = –10dBm
–50
0
20
35
3RF – 3LO
(RF = 5090MHz)
–70
GC
6
–45 –25
40
2RF – 2LO
(RF = 5130MHz)
–40
–60
10
45
LO = 5010MHz
–10
ISOLATION (dB)
24
–40
IFOUT
(RF = 5250MHz)
10
OUTPUT POWER (dBm)
GC (dB), IIP3 (dBm), P1dB (dBm)
20
IIP3
26
2 × 2 and 3 × 3 Spurs
vs LO Power
DISTRIBUTION (%)
28
Single-Tone IF Output Power, 2 × 2
and 3 × 3 Spurs vs RF Input Power
RELATIVE SPUR LEVEL (dBc)
Conversion Gain, IIP3 and RF Input
P1dB vs Temperature
6.8 6.9 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9
CONVERSION GAIN (dB)
5544 G16
0
23.7 24.1 24.5 24.9 25.3 25.7 26.1 26.5 26.9
IIP3 (dBm)
5544 G17
0
9.9 10.3 10.7 11.1 11.5 11.9 12.3 12.7
SSB NOISE FIGURE (dB)
5544 G18
5544f
6
LTC5544
Typical AC Performance Characteristics
High Side LO
VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests, Δf = 2MHz),
IF = 240MHz, unless otherwise noted. Test circuit shown in Figure 1.
Conversion Gain and IIP3
vs RF Frequency
24
13
24
13
22
11
22
11
18
GC
7
PLO = –1dBm
PLO = 2dBm
PLO = 5dBm
20
18
5
16
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8
RF FREQUENCY (GHz)
Input P1dB vs RF Frequency
15
11
TC = –40°C
TC = 25°C
9
TC = 85°C
TC = 105°C
GC (dB)
22
INPUT P1dB (dBm)
13
24
IIP3 (dBm)
7
16
15
IIP3
GC
VCC = VCCIF
VCC = 3.1V
VCC = 3.3V
VCC = 3.5V
5544 G20
Conversion Gain and IIP3
vs RF Frequency
20
9
GC
5
16
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8
RF FREQUENCY (GHz)
5544 G19
26
15
IIP3
GC (dB)
9
20
IIP3 (dBm)
26
IIP3
GC (dB)
15
26
IIP3 (dBm)
Conversion Gain and IIP3
vs RF Frequency
7
18
VCCIF = 5V
14
13
12
VCCIF = 3.3V
11
10
PLO = –1dBm
PLO = 2dBm
PLO = 5dBm
9
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8
RF FREQUENCY (GHz)
5544 G22
5
16
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8
RF FREQUENCY (GHz)
5544 G21
5250MHz Conversion Gain,
IIP3 and NF vs LO Power
SSB NF and DSB NF
vs RF Frequency
25
16
SSB NF
GC (dB), IIP3 (dBm)
DSB NF
8
6
4
2
16
21
12
10
18
IIP3
TC = –40°C
TC = 25°C
TC = 85°C
TC = 105°C
0
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
RF FREQUENCY (GHz)
5544 G23
19
14
NF
17
12
15
10
13
11
9
GC
7
5
–3 –2 –1
TC = –40°C 8
TC = 25°C 6
TC = 85°C
4
0 1 2 3 4 5
LO INPUT POWER (dBm)
SSB NF (dB)
SSB NF, DSB NF (dB)
14
20
23
2
6
7
0
5544 G24
5544f
7
LTC5544
Pin Functions
GND (Pins 1, 8, 9, 11, Exposed Pad Pin 17): Ground.
These pins must be soldered to the RF ground plane on
the circuit board. The exposed pad metal of the package
provides both electrical contact to ground and good thermal
contact to the printed circuit board.
nected and must be externally connected to a regulated
3.3V supply, with bypass capacitors located close to the
pins. Typical current consumption is 96mA.
RF (Pin 2): Single-Ended Input for the RF Signal. This pin
is internally connected to the primary side of the RF input
transformer, which has low DC resistance to ground. A
series DC-blocking capacitor should be used to avoid
damage to the integrated transformer when DC voltage
is present at the RF input. The RF input is impedance
matched, as long as the LO input is driven with a 2dBm
±5dB source between 4.2GHz and 5.8GHz.
LO (Pin 10): Single-Ended Input for the Local Oscillator.
This pin is internally connected to the primary side of the
RF input transformer, which has low DC resistance to
ground. A series DC blocking capacitor must be used to
avoid damage to the integrated transformer if DC voltage
is present at the LO input.
LOBIAS (Pin 6): This Pin Allows Adjustment of the LO
Buffer Current. Typical DC voltage is 2.2V.
TEMP (Pin 12): Temperature Sensing Diode. This pin is
connected to the anode of a diode that may be used to
measure the die temperature, by forcing a current and
measuring the voltage.
CT (Pin 3): RF Transformer Secondary Center-Tap. This
pin may require a bypass capacitor to ground. See the
Applications Information section. This pin has an internally
generated bias voltage of 1.2V. It must be DC-isolated
from ground and VCC.
IFGND (Pin 13): DC Ground Return for the IF Amplifier.
This pin must be connected to ground to complete the IF
amplifier’s DC current path. Typical DC current is 98mA.
SHDN (Pin 4): Shutdown Pin. When the input voltage is
less than 0.3V, the IC is enabled. When the input voltage
is greater than 3V, the IC is disabled. Typical SHDN pin
input current is less than 10μA. This pin must not be
allowed to float.
IF – (Pin 14) and IF + (Pin 15): Open-Collector Differential
Outputs for the IF Amplifier. These pins must be connected
to a DC supply through impedance matching inductors, or
a transformer center-tap. Typical DC current consumption
is 49mA into each pin.
VCC1 (Pin 5) and VCC2 (Pin 7): Power Supply Pins for the
LO Buffer and Bias Circuits. These pins are internally con-
IFBIAS (Pin 16): This Pin Allows Adjustment of the IF
Amplifier Current. Typical DC voltage is 2.1V.
Block Diagram
16
15
14
IFBIAS IF +
17
13
IF –
IFGND
IF
AMP
2
3
4
EXPOSED
PAD
LO
RF
LO
AMP
CT
SHDN
TEMP
12
10
PASSIVE
MIXER
BIAS
VCC2
VCC1
5
7
LOBIAS
6
5544 BD
GND PINS ARE NOT SHOWN
5544f
8
LTC5544
Test Circuit
IFOUT
240MHz
50Ω
4:1
T1
C5
L1
VCCIF
3.1V TO 5.3V
L2
C8
C4
16
15
IFBIAS
1 GND
14
IF+
IF –
LTC5544
13
IFGND
TEMP 12
C1
RFIN
50Ω
2 RF
GND 11
L4
C2
SHDN
(0V/3.3V)
17
GND
3 CT
4 SHDN
LOIN
50Ω
GND 9
VCC1
LOBIAS
6
5
VCC
3.1V TO 3.5V
VCC2
GND
8
7
C6
5544 F01
C7
RF
0.015”
GND DC1885A
BOARD
BIAS STACK-UP
GND (NELCO N4000-13)
0.062”
0.015”
L1, L2 vs IF
Frequencies
C3
LO 10
REF DES
VALUE
SIZE
COMMENTS
C1
0.6pF
0402
AVX ACCU-P
C2
Open
0402
IF (MHz)
L1, L2 (nH)
140
220
190
150
C3
1.2pF
0402
AVX ACCU-P
240
150
C4, C6
22pF
0402
AVX
305
82
C5
1000pF
0402
AVX
380
56
C7, C8
1µF
0603
AVX
456
39
L1, L2
150nH
0603
Coilcraft 0603CS
L4
2.2nH
0402
Coilcraft 0402HP
T1
TC4-1W-7ALN+
Mini-Circuits
Note: For IF = 250MHz to 500MHz, use TC4-1W-17LN+ for T1
Figure 1. Standard Downmixer Test Circuit Schematic (240MHz IF)
5544f
9
LTC5544
Applications Information
Introduction
The LTC5544 consists of a high linearity passive doublebalanced mixer core, IF buffer amplifier, LO buffer amplifier and bias/shutdown circuits. See the Block Diagram
section for a description of each pin function. The RF and
LO inputs are single-ended. The IF output is differential.
Low side or high side LO injection can be used. The
evaluation circuit, shown in Figure 1, utilizes bandpass IF
output matching and an IF transformer to realize a 50Ω
single-ended IF output. The evaluation board layout is
shown in Figure 2.
For the RF input to be matched, the LO input must
be driven. A broadband input match is realized with
C1 = 0.6pF and L4 = 2.2nH. The measured RF input return
loss is shown in Figure 4 for LO frequencies of 4.4GHz,
5GHz and 5.6GHz. These LO frequencies correspond to
the lower, middle and upper values of the LO range. As
shown in Figure 4, the RF input impedance is somewhat
dependent on LO frequency.
The RF input impedance and input reflection coefficient,
versus RF frequency, is listed in Table 1. The reference
plane for this data is Pin 2 of the IC, with no external
matching, and the LO is driven at 5GHz.
LTC5544
TO MIXER
RFIN
C1
2
RF
L4
3
CT
C2
5544 F02
5544 F03
Figure 2. Evaluation Board Layout
Figure 3. RF Input Schematic
RF Input
The secondary winding of the RF transformer is internally
connected to the passive mixer. The center-tap of the
transformer secondary is connected to Pin 3 (CT) to allow
the connection of bypass capacitor, C2. The value of C2 is
LO frequency-dependent and can be tuned for better LO
leakage performance. When used, C2 should be located
within 2mm of Pin 3 for proper high frequency decoupling.
The nominal DC voltage on the CT pin is 1.2V.
10
0
5
RF PORT RETURN LOSS (dB)
The mixer’s RF input, shown in Figure 3, is connected to
the primary winding of an integrated transformer. A 50Ω
match is realized with a series capacitor (C1) and a shunt
inductor (L4). The primary side of the RF transformer
is DC-grounded internally and the DC resistance of the
primary is approximately 2.4Ω. A DC blocking capacitor
is needed if the RF source has DC voltage present.
10
LO = 4.4GHz
15
20
25
LO = 5.6GHz
30
LO = 5GHz
35
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
RF FREQUENCY (GHz)
5544 F04
Figure 4. RF Input Return Loss
5544f
LTC5544
Applications Information
Table 1. RF Input Impedance and S11
(at Pin 2, No External Matching, LO Input Driven at 5GHz)
S11
FREQUENCY
(GHz)
INPUT
IMPEDANCE
MAG
ANGLE
4.0
85.8 + j54.1
0.44
34.8
4.2
89.2 + j45.6
0.41
31.2
4.4
90.9 + j41.3
0.40
29
4.6
95.9 + j33.6
0.38
23.2
4.8
91.4 + j17.1
0.31
15.6
5.0
72.9 + j10.7
0.21
20.1
5.2
66.7 + j24.1
0.25
43.6
5.4
70.8 + j29.1
0.29
40.9
5.6
73.1 + j26.2
0.28
36.6
5.8
69.2 + j23.9
0.25
39.9
6.0
67.3 + j25.7
0.26
43.7
low), the internal bias circuit provides a regulated 4mA
current to the amplifier’s bias input, which in turn causes
the amplifiers to draw approximately 90mA of DC current.
This 4mA reference current is also connected to LOBIAS
(Pin 6) to allow modification of the amplifier’s DC bias
current for special applications. The recommended application circuits require no LO amplifier bias modification,
so this pin should be left open-circuited.
The nominal LO input level is +2dBm although the limiting
amplifiers will deliver excellent performance over a ±3dB
input power range. LO input power greater than +5dBm
may be used with slightly degraded performance.
The LO input impedance and input reflection coefficient,
versus frequency, is shown in Table 2.
Table 2. LO Input Impedance vs Frequency
(at Pin 10, No External Matching)
LO Input
S11
FREQUENCY
(GHz)
INPUT
IMPEDANCE
MAG
ANGLE
4.0
22.7 + j14.7
0.42
140.2
4.2
24.4 + j18.6
0.41
129.9
4.4
28.2 + j22.5
0.39
118.1
4.6
33.2 + j25.3
0.35
106.7
4.8
39.7 + j26.4
0.30
95
The mixer’s LO input is directly connected to the primary
winding of an integrated transformer. A 50Ω match is
realized with a series 1.2pF capacitor (C3). Measured LO
input return loss is shown in Figure 6.
5.0
47.4 + j24.3
0.24
82.1
5.2
52.2 + j16.9
0.16
73.3
The LO amplifiers are powered through VCC1 and VCC2
(Pin 5 and Pin 7). When the chip is enabled (SHDN =
5.8
6.0
The mixer’s LO input circuit, shown in Figure 5, consists
of a balun transformer and a two-stage high speed limiting
differential amplifier to drive the mixer core. The LTC5544’s
LO amplifiers are optimized for the 4.2GHz to 5.8GHz
LO frequency range. LO frequencies above or below this
frequency range may be used with degraded performance.
5.4
52 + j9.4
0.09
72.7
5.6
49.9 + j3.8
0.04
88.8
47.7 – j1
0.03
–156.5
44.2 – j6.2
0.09
–129.4
LO BUFFER
TO
MIXER
LO
10
4mA
BIAS
LOBIAS
6
5
VCC1
7
C3
LOIN
LO PORT RETURN LOSS (dB)
0
LTC5544
5
10
15
20
25
30
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
LO FREQUENCY (GHz)
5544 F06
VCC2
5544 F05
Figure 5. LO Input Schematic
Figure 6. LO Input Return Loss
5544f
11
LTC5544
Applications Information
IF Output
The IF amplifier, shown in Figure 7, has differential
open-collector outputs (IF+ and IF –), a DC ground return
pin (IFGND), and a pin for modifying the internal bias
(IFBIAS). The IF outputs must be biased at the supply
voltage (VCCIF), which is applied through matching inductors L1 and L2. Alternatively, the IF outputs can be biased
through the center tap of a transformer. The common
node of L1 and L2 can be connected to the center tap of
the transformer. Each IF output pin draws approximately
49mA of DC supply current (98mA total). IFGND (Pin 13)
must be grounded or the amplifier will not draw DC current.
For the highest conversion gain, high-Q wire-wound chip
inductors are recommended for L1 and L2, especially when
using VCCIF = 3.3V. Low cost multilayer chip inductors may
be substituted, with a slight degradation in performance.
Grounding through inductor L3 may improve LO-IF and
RF-IF leakage performance in some applications, but is
otherwise not necessary. High DC resistance in L3 will
reduce the IF amplifier supply current, which will degrade
RF performance.
T1
IFOUT
R1
(OPTION TO
REDUCE
DC POWER)
LTC5544
4:1
C10
L1
L2
VCCIF
C8
16
15
IF+
IFBIAS
VCC
4mA
98mA
14
IF –
L3
(OR SHORT)
13
IFGND
IF
AMP
transformation. It is also possible to eliminate the IF transformer and drive differential filters or amplifiers directly.
The IF output impedance can be modeled as 332Ω in
parallel with 1.7pF at IF frequencies. An equivalent smallsignal model is shown in Figure 8. Frequency-dependent
differential IF output impedance is listed in Table 3. This
data is referenced to the package pins (with no external
components) and includes the effects of IC and package
parasitics.
LTC5544
15
IF +
14
RIF
IF –
CIF
5544 F08
Figure 8. IF Output Small-Signal Model
Table 3. IF Output Impedance vs Frequency
FREQUENCY (MHz)
DIFFERENTIAL OUTPUT
IMPEDANCE (RIF || XIF (CIF))
90
351 || –j707 (2.5pF)
140
341 || –j494 (2.3pF)
190
334 || –j441 (1.9pF)
240
332 || –j390 (1.7pF)
300
325 || –j312 (1.7pF)
380
318 || –j246 (1.7pF)
456
304 || –j205 (1.7pF)
Transformer-Based Bandpass IF Matching
BIAS
5544 F07
Figure 7. IF Amplifier Schematic with
Transformer-Based Bandpass Match
For optimum single-ended performance, the differential IF
outputs must be combined through an external IF transformer or discrete IF balun circuit. The evaluation board
(see Figures 1 and 2) uses a 4:1 ratio IF transformer for
impedance transformation and differential to single-ended
The IF output can be matched for IF frequencies as low
as 40MHz, or as high as 500MHz, using the bandpass IF
matching shown in Figures 1 and 7. L1 and L2 resonate
with the internal IF output capacitance at the desired IF
frequency. The value of L1, L2 is calculated as follows:
L1, L2 = 1/[(2 π fIF)2 • 2 • CIF]
where CIF is the internal IF capacitance (listed in Table 3).
Values of L1 and L2 are tabulated in Figure 1 for various
IF frequencies
5544f
12
LTC5544
Applications Information
Discrete IF Balun Matching
For many applications, it is possible to replace the IF
tran­sformer with the discrete IF balun shown in Figure 9.
The values of L5, L6, C13 and C14 are calculated to realize
a 180° phase shift at the desired IF frequency and provide
a 50Ω single-ended output, using the following equations.
Inductor L7 is used to cancel the internal capacitance
CIF and supplies bias voltage to the IF pin. C15 is a DC
blocking capacitor.
L5, L6 =
RIF •ROUT
C13, C14 =
ωIF
Table 4. Performance Comparison with VCCIF = 3.3V and 5V
(RF = 5250MHz, Low Side LO, IF = 240MHz)
VCCIF
(V)
ICCIF
(mA)
GC
(dB)
P1dB
(dBm)
IIP3
(dBm)
NF
(dB)
3.3
98
7.4
11.4
25.9
11.3
5.0
101
7.4
14.6
26.5
11.4
L5
R1
(OPTION TO
REDUCE
DC POWER)
C13
16
IFBIAS
LTC5544
VCCIF
IFOUT
C15
L6
C14
L3
98mA (OR SHORT)
L7
15
IF+
14
IF –
13
IFGND
1
ωIF • RIF •ROUT
VCC
|X |
L7 = IF
ωIF
5544 F09
Figure 9. IF Amplifier Schematic with Discrete IF Balun
IIP3
The IF amplifier delivers excellent performance with
VCCIF = 3.3V, which allows the VCC and VCCIF supplies
to be common. With VCCIF increased to 5V, the RF input
P1dB increases by more than 3dB, at the expense of higher
power consumption. Mixer performance at 5250MHz is
shown in Table 4 with VCCIF = 3.3V and 5V.
11
24
9
22
GC
IF = 456MHz
LOW SIDE LO
TC4-1W-17LN+ BALUN
DISCRETE BALUN
7
5
3
18
4.5 4.7 4.9 5.1 5.3 5.5 5.7 5.9 6.1 6.3
RF FREQUENCY (GHz)
5544 F10
Figure 10. Conversion Gain and IIP3 vs RF Frequency
0
IF PORT RETURN LOSS (dB)
IF Amplifier Bias
26
20
L5, L6 = 36nH, L7 = 82nH and C13, C14 = 3.3pF
Measured IF output return losses for transformer-based
bandpass IF matching and discrete balun IF matching
(456MHz IF frequency) are plotted in Figure 11. A discrete
balun has less insertion loss than a balun transformer,
but the IF bandwidth of a discrete balun is less than that
of a transformer.
13
28
GC (dB)
The typical performances of the LTC5544 using a discrete
IF balun matching and a transformer-based IF matching
are shown in Figure 10. With an IF frequency of 456MHz,
the actual components values for the discrete balun are:
BIAS
IIP3 (dBm)
These equations give a good starting point, but it is usually
necessary to adjust the component values after building
and testing the circuit. The final solution can be achieved
with less iteration by considering the parasitics of L7 in
the previous calculation.
IF
AMP
4mA
5
L1, L2 = 150 nH
L1, L2 = 82nH
L1, L2 = 39nH
DISCRETE BALUN 456MHz
10
15
20
25
30
100 150 200 250 300 350 400 450 500 550 600
IF FREQUENCY (MHz)
5544 F11
Figure 11. IF Output Return Loss
5544f
13
LTC5544
Applications Information
The IFBIAS pin (Pin 16) is available for reducing the DC
current consumption of the IF amplifier, at the expense of
reduced performance. This pin should be left open-circuited
for optimum performance. The internal bias circuit produces a 4mA reference for the IF amplifier, which causes
the amplifier to draw approximately 98mA. If resistor R1
is connected to Pin 16 as shown in Figure 6, a portion of
the reference current can be shunted to ground, resulting
in reduced IF amplifier current. For example, R1 = 1kΩ
will shunt away 1.5mA from Pin 16 and the IF amplifier
current will be reduced by 40% to approximately 59mA.
The nominal, open-circuit DC voltage at Pin 16 is 2.1V.
Table 5 lists RF performance at 5250MHz versus IF amplifier current.
Table 5. Mixer Performance with Reduced IF Amplifier Current
(RF = 5250MHz, Low Side LO, IF = 240MHz, VCC = VCCIF = 3.3V)
R1
(kΩ)
ICCIF
(mA)
GC
(dB)
IIP3
(dBm)
P1dB
(dBm)
NF
(dB)
OPEN
98
7.4
25.9
11.4
11.3
4.7
89
7.2
25.7
11.5
11.4
2.2
77
6.9
25.2
11.6
11.5
1.0
59
6.3
23.8
11.3
11.6
(RF = 5250MHz, High Side LO, IF = 240MHz, VCC = VCCIF = 3.3V)
LTC5544
VCC1
5
SHDN
500Ω
4
5544 F12
Figure 12. Shutdown Input Circuit
Temperature Diode
The LTC5544 provides an on-chip diode at Pin 12 (TEMP)
for chip temperature measurement. Pin 12 is connected to
the anode of an internal ESD diode with its cathode connected to internal ground. The chip temperature can be
measured by injecting a constant DC current into Pin 12
and measuring its DC voltage. The voltage vs temperature
coefficient of the diode is about –1.73mV/°C with 10µA
current injected into the TEMP pin. Figure 13 shows a
typical temperature-voltage behavior when 10µA and 80µA
currents are injected into Pin 12.
ICCIF
(mA)
GC
(dB)
IIP3
(dBm)
P1dB
(dBm)
NF
(dB)
900
OPEN
98
7.3
24.0
11.4
11.7
850
4.7
89
7.0
23.8
11.4
11.9
800
2.2
77
6.6
23.5
11.4
12.2
1.0
59
5.8
22.6
11.3
12.4
Shutdown Interface
Figure 12 shows a simplified schematic of the SHDN pin
interface. To disable the chip, the SHDN voltage must be
higher than 3.0V. If the shutdown function is not required,
the SHDN pin should be connected directly to GND. The
voltage at the SHDN pin should never exceed the power
supply voltage (VCC) by more than 0.3V. If this should
occur, the supply current could be sourced through the
ESD diode, potentially damaging the IC.
The SHDN pin must be pulled high or low. If left floating,
then the on/off state of the IC will be indeterminate. If a
three-state condition can exist at the SHDN pin, then a
pull-up or pull-down resistor must be used.
TEMP DIODE VOLTAGE (mV)
R1
(kΩ)
80µA
750
700
650
10µA
600
550
500
450
400
–40
40
80
–20
20
60
0
JUNCTION TEMPERATURE (°C)
100
5544 F13
Figure 13. TEMP Diode Voltage vs Junction Temperature (TJ)
Supply Voltage Ramping
Fast ramping of the supply voltage can cause a current
glitch in the internal ESD protection circuits. Depending on
the supply inductance, this could result in a supply voltage transient that exceeds the maximum rating. A supply
voltage ramp time of greater than 1ms is recommended.
5544f
14
LTC5544
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
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)
R = 0.115
TYP
0.75 ± 0.05
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
5544f
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
LTC5544
Typical Application
900MHz IF Output Matching
IFOUT
50Ω
Conversion Gain,
IIP3 and NF vs RF Frequency
TM4-1
(SYNERGY)
3.3pF
IF+
IF –
IFGND TEMP
IF
0.6pF
RFIN
50Ω
1.2pF
RF
LO
LO
LOIN
50Ω
2.2nH
SHDN
SHDN
IIP3 (dBm), SSB NF (dB)
22pF
22nH
22
5
GC
18
4
16
3
14
2
SSB NF
12
5.1
5.3 5.5 5.7 5.9
RF FREQUENCY (GHz)
1
6.1
0
6.3
5544 TA02b
VCC2
VCC1
VCC
3.3V
7
6
20
10
4.9
BIAS
8
IF = 900MHz
LOW SIDE LO
24
GC (dB)
1µF
9
26
1000pF
1000pF
22nH
IIP3
28
1000pF
VCCIF
3.3V
10
30
5544 TA02a
1µF
22pF
Related Parts
PART NUMBER DESCRIPTION
COMMENTS
Infrastructure
LTC554X
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LT 5527
400MHz to 3.7GHz, 5V Downconverting Mixer
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LT5557
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®
LTC559x
600MHz to 4.5GHz Dual Downconverting Mixer Family 8.5dB Gain, 26.5dBm IIP3, 9.9dB NF, 3.3V/380mA Supply
LTC5569
300MHz to 4GHz 3.3V Dual Downconverting Mixer
2dB Gain, 26.8dBm IIP3 and 11.7dB NF at 1950MHz, 3.3V/180mA Supply
LTC6400-X
300MHz Low Distortion IF Amp/ADC Driver
Fixed Gain of 8dB, 14dB, 20dB and 26dB; >36dBm OIP3 at 300MHz, Differential I/O
LTC6416
2GHz 16-Bit ADC Buffer
40dBm OIP3 to 300MHz, Programmable Fast Recovery Output Clamping
LTC6412
31dB Linear Analog VGA
35dBm OIP3 at 240MHz, Continuous Variable Gain Range –14dB to 17dB
LT5554
Ultralow Distort IF Digital VGA
48dBm OIP3 at 200MHz, 2dB to 18dB Gain Range, 0.125dB Gain Steps
LT5578
400MHz to 2.7GHz Upconverting Mixer
27dBm OIP3 at 900MHz, 24.2dBm at 1.95GHz, Integrated RF Transformer
LT5579
1.5GHz to 3.8GHz Upconverting Mixer
27.3dBm OIP3 at 2.14GHz, NF = 9.9dB, 3.3V Supply, Single-Ended LO and RF Ports
LTC5588-1
200MHz to 6GHz I/Q Modulator
31dBm OIP3 at 2.14GHz, –160.6dBm/Hz Noise Floor
RF Power Detectors
LTC5587
6GHz RMS Detector with 12-Bit ADC
40dB Dynamic Range, ±1dB Accuracy Over Temperature, 3mA Current, 500ksps
LT5581
6GHz Low Power RMS Detector
40dB Dynamic Range, ±1dB Accuracy Over Temperature, 1.5mA Supply Current
LTC5582
40MHz to 10GHz RMS Detector
57dB Dynamic Range, ±0.5dB Accuracy Over Temperature, ±0.2dB Linearity Error
LTC5583
Dual 6GHz RMS Power Detector
Up to 60dB Dynamic Range, ±0.5dB Accuracy Over Temperature, >50dB Isolation
LTC2208
16-Bit, 130Msps ADC
78dBFS Noise Floor, >83dB SFDR at 250MHz
LTC2285
Dual 14-Bit, 125Msps Low Power ADC
72.4dB SNR, 88dB SFDR, 790mW Power Consumption
LTC2268-14
Dual 14-Bit, 125Msps Serial Output ADC
73.1dB SNR, 88dB SFDR, 299mW Power Consumption
ADCs
5544f
16 Linear Technology Corporation
LT 0312 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
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