LT5568-2
1
55682f
GSM RF OUTPUT POWER (dBm)
–10
0
EVM (%RMS)
NOISE FLOOR AT 6MHz
OFFSET (dBc/100kHz)
1
3
4
5
–6 –2 0
2
–106
–104
–100
–98
–96
–102
–8 –4 246
55682 TA02
EVM
NOISE
GSM/EDGE Optimized,
High Linearity Direct
Quadrature Modulator
The LT
®
5568-2 is a direct I/Q modulator designed for high
performance wireless applications, including wireless
infrastructure. It allows direct modulation of an RF signal
using differential baseband I and Q signals. It supports
GSM, EDGE, CDMA, CDMA2000 and other systems that
operate in the 850MHz to 965MHz band. It may be confi g-
ured as an image reject upconverting mixer, by applying
90° phase-shifted signals to the I and Q inputs. The I/Q
baseband inputs consist of voltage-to-current converters
that in turn drive double-balanced mixers. The outputs of
these mixers are summed and applied to an on-chip RF
transformer, which converts the differential mixer signals
to a 50Ω single-ended output. The four balanced I and Q
baseband input ports are intended for DC coupling from a
source with a common mode voltage level of about 0.5V.
The LO path consists of an LO buffer with single-ended
input, and precision quadrature generators that produce
the LO drive for the mixers. The supply voltage range is
4.5V to 5.25V.
■ Infrastructure Tx for GSM/Cellular Bands
■ Image Reject Up-Converters for Cellular Bands
■ Low-Noise Variable Phase-Shifter for 700MHz to
1050MHz Local Oscillator Signals
■ RFID Reader
■ Optimized Image Rejection for 850MHz to 965MHz
■ High OIP3: +22.9dBm at 900MHz
■ Low Output Noise Floor at 5MHz Offset:
No RF: –159.4dBm/Hz
P
OUT = 4dBm: –153dBm/Hz
■ Integrated LO Buffer and LO Quadrature Phase
Generator
■ 50Ω AC-Coupled Single-Ended LO and RF Ports
■ 50Ω DC Interface to Baseband Inputs
■ Low Carrier Leakage: –43dBm at 900MHz
■ High Image Rejection: –52dBc at 900MHz
■ 16-Lead 4mm × 4mm QFN Package
850MHz to 965MHz Direct Conversion Transmitter Application
APPLICATIO S
U
FEATURES DESCRIPTIO
U
TYPICAL APPLICATIO
U
GSM EVM and Noise
vs RF Output Power at 900MHz
90°
0°
LT5568-2
BASEBAND
GENERATOR
PA
VCO/SYNTHESIZER
RF = 850MHz
TO 965MHz
100nF
x 2
EN
5V
V-I
V-I
I-CHANNEL
Q-CHANNEL BALUN
VCC
55682 TA01
I-DAC
Q-DAC
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
LT5568-2
2
55682f
Supply Voltage .........................................................5.5V
Common Mode Level of BBPI, BBMI and
BBPQ, BBMQ .......................................................2.5V
Operating Ambient Temperature
(Note 2) ............................................... –40°C to 85°C
Storage Temperature Range ................... –65°C to 125°C
Voltage on Any Pin
Not to Exceed ...................... –500mV to VCC + 500mV
CAUTION: This part is sensitive to ESD. It is very
important that proper ESD precautions be observed
when handling the LT5568-2.
(Note 1)
ABSOLUTE AXI U RATI GS
W
WW
U
V
CC = 5V, EN = High, TA = 25°C, fLO = 900MHz, fRF = 902MHz, PLO = 0dBm.
BBPI, BBMI, BBPQ, BBMQ inputs 0.54VDC, Baseband Input Frequency = 2MHz, I&Q 90° shifted (upper side-band selection).
PRF, OUT = –10dBm, unless otherwise noted. (Note 3)
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
RF Output (RF)
fRF RF Frequency Range
RF Frequency Range
–3dB Bandwidth
–1dB Bandwidth
0.6 to 1.1
0.7 to 1
GHz
GHz
S22, ON RF Output Return Loss EN = High (Note 6) –16 dB
S22, OFF RF Output Return Loss EN = Low (Note 6) –18 dB
NFloor RF Output Noise Floor No Input Signal (Note 8)
POUT = 4dBm (Note 9)
POUT = 4dBm (Note 10)
–159.4
–153
–152.6
dBm/Hz
dBm/Hz
dBm/Hz
GPConversion Power Gain POUT/PIN, I&Q –9 –6.8 –3 dB
GVConversion Voltage Gain 20 • Log (VOUT, 50Ω/VIN, DIFF, I or Q) –6.8 dB
POUT Absolute Output Power 1VP-P DIFF CW Signal, I and Q –2.8 dBm
G3LO vs LO 3 • LO Conversion Gain Difference (Note 17) –23 dB
OP1dB Output 1dB Compression (Note 7) 8.6 dBm
OIP2 Output 2nd Order Intercept (Notes 13, 14) 59 dBm
OIP3 Output 3rd Order Intercept (Notes 13, 15) 22.9 dBm
PIN CONFIGURATION
16 15 14 13
5 6 7 8
TOP VIEW
9
10
11
12
4
3
2
1EN
GND
LO
GND
GND
RF
GND
GND
BBMI
GND
BBPI
VCC
BBMQ
GND
BBPQ
VCC
17
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
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LT5568-2EUF#PBF LT5568-2EUF#TRPBF 55682 16-Lead (4mm × 4mm) Plastic QFN –40°C to 85°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based fi nish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/
LT5568-2
3
55682f
V
CC = 5V, EN = High, TA = 25°C, fLO = 900MHz, fRF = 902MHz, PLO = 0dBm.
BBPI, BBMI, BBPQ, BBMQ inputs 0.54VDC, Baseband Input Frequency = 2MHz, I&Q 90° shifted (upper side-band selection).
PRF, OUT = –10dBm, unless otherwise noted. (Note 3)
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: Specifi cations over the –40°C to 85°C temperature range are assured
by design, characterization and correlation with statistical process controls.
Note 3: Tests are performed as shown in the confi guration of Figure 7.
Note 4: On each of the four baseband inputs BBPI, BBMI, BBPQ and BBMQ.
Note 5: V(BBPI) – V(BBMI) = 1VDC, V(BBPQ) – V(BBMQ) = 1VDC.
Note 6: Maximum value within 850MHz to 965MHz.
Note 7: An external coupling capacitor is used in the RF output line.
Note 8: At 20MHz offset from the LO signal frequency.
Note 9: At 20MHz offset from the CW signal frequency.
Note 10: At 5MHz offset from the CW signal frequency.
Note 11: RF power is within 10% of fi nal value.
Note 12: RF power is at least 30dB lower than in the ON state.
Note 13: Baseband is driven by 2MHz and 2.1MHz tones. Drive level is set
in such a way that the two resulting RF tones are –10dBm each.
Note 14: IM2 measured at LO frequency + 4.1MHz.
Note 15: IM3 measured at LO frequency + 1.9MHz and LO frequency + 2.2MHz.
Note 16: Amplitude average of the characterization data set without image
or LO feedthrough nulling (unadjusted).
Note 17: The difference in conversion gain between the spurious signal at
f = 3 • LO – BB versus the conversion gain at the desired signal at f = LO +
BB for BB = 2MHz and LO = 900MHz.
Note 18: The input voltage corresponding to the output P1dB.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
IR Image Rejection fBB = 100kHz (Note 16) –52 dBc
LOFT Carrier Leakage
(LO Feedthrough)
EN = High, PLO = 0dBm (Note 16)
EN = Low, PLO = 0dBm (Note 16)
–43
–65
dBm
dBm
LO Input (LO)
fLO LO Frequency Range 0.6 to 1.1 GHz
PLO LO Input Power –10 0 5 dBm
S11, ON LO Input Return Loss EN = High (Note 6) –15 dB
S11, OFF LO Input Return Loss EN = Low (Note 6) –2.5 dB
NFLO LO Input Referred Noise Figure (Note 5) at 900MHz 14.7 dB
GLO LO to RF Small Signal Gain (Note 5) at 900MHz 14.7 dB
IIP3LO LO Input 3rd Order Intercept (Note 5) at 900MHz –3 dBm
Baseband Inputs (BBPI, BBMI, BBPQ, BBMQ)
BWBB Baseband Bandwidth –3dB Bandwidth 380 MHz
VCMBB DC Common Mode Voltage (Note 4) 0.54 V
RIN, SE Single-Ended Input Resistance (Note 4) 47 Ω
PLO2BB Carrier Feedthrough on BB POUT = 0 (Note 4) –38 dBm
IP1dB Input 1dB Compression Point Differential Peak-to-Peak (Notes 7, 18) 4.3 VP-P, DIFF
Power Supply (VCC)
VCC Supply Voltage 4.5 5 5.25 V
ICC, ON Supply Current EN = High 80 110 145 mA
ICC, OFF Supply Current, Sleep Mode EN = 0V 100 µA
tON Turn-On Time EN = Low to High (Note 11) 0.3 µs
tOFF Turn-Off Time EN = High to Low (Note 12) 1.4 µs
Enable (EN), Low = Off, High = On
Enable Input High Voltage
Input High Current
EN = High
EN = 5V
1.0
245
V
µA
Sleep Input Low Voltage
Input Low Current
EN = Low
EN = 0V 0.01
0.5 V
µA
LT5568-2
4
55682f
SUPPLY VOLTAGE (V)
4.5
SUPPLY CURRENT (mA)
120
110
100
90
55682 G01
55.5
85°C
25°C
–40°C
LO FREQUENCY (MHz)
–14
RF OUTPUT POWER (dBm)
–6
–10
–12
–8
–4
–2
0
55682 G02
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
550 650 750 850 950 1050 1150 1250
LO FREQUENCY (MHz)
–18
VOLTAGE GAIN (dB)
–10
–14
–16
–12
–8
–6
–4
55682 G03
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
550 650 750 850 950 1050 1150 1250
LO FREQUENCY (MHz)
12
OIP3 (dBm)
20
16
14
18
22
24
26
55682 G04
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
550 650 750 850 950 1050 1150 1250
fBB, 1 = 2MHz
fBB, 2 = 2.1MHz
LO FREQUENCY (MHz)
550
45
OIP2 (dBm)
60
55
50
65
70
650 750 850 950
55682 G05
1050 1150 1250
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
fIM2 = fBB, 1 + fBB, 2 + fLO
fBB, 1 = 2MHz
fBB, 2 = 2.1MHz
LO FREQUENCY (MHz)
550
2
OP1dB (dBm)
6
4
8
10
650 750 850 950
55682 G06
1050 1150 1250
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
LO FREQUENCY (MHz)
550
–46
LO FEEDTHROUGH (dBm)
–42
–44
–40
–38
650 750 850 950
55682 G07
1050 1150 1250
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
2 • LO FREQUENCY (GHz)
1.1
–65
P(2 • LO) (dBm)
–55
–60
–50
–45
1.3 1.5 1.7 1.9
55682 G08
2.1 2.3 2.5
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
3 • LO FREQUENCY (GHz)
1.65
–70
–65
P(3 • LO) (dBm)
–55
–60
–50
–45
1.95 2.25 2.55 2.85
55682 G09
3.15 3.45 3.75
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
VCC = 5V, EN = High, TA = 25°C, fLO = 900MHz,
PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.54VDC, Baseband Input Frequency fBB = 2MHz, I&Q 90° shifted. fRF = fBB + fLO (upper
sideband selection). PRF, OUT = –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3)
Supply Current vs Supply Voltage
RF Output Power vs LO Frequency
at 1VP-P Differential Baseband Drive
Voltage Gain vs LO Frequency
Output IP3 vs LO Frequency
Output IP2 vs LO Frequency
Output 1dB Compression
vs LO Frequency
TYPICAL PERFOR A CE CHARACTERISTICS
UW
LO Feedthrough to RF Output
vs LO Frequency
2 • LO Leakage to RF Output
vs 2 • LO Frequency
3 • LO Leakage to RF Output
vs 3 • LO Frequency
LT5568-2
5
55682f
LO INPUT POWER (dBm)
–20
–55
IMAGE REJECTION (dBc)
–45
–50
–40
–35
–16 –12 –8 –4
55682 G14
048
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
PRF = –10dBm
fBB = 100kHz
RF FREQUENCY (MHz)
550
–163
–163
NOISE FLOOR (dBm/Hz)
–160
–161
–159
–158
650 750 850 950
55682 G10
1050 1150 1250
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
fLO = 900MHz
(FIXED)
NO RF
LO FREQUENCY (MHz)
550
–55
IMAGE REJECTION (dBc)
–40
–50
–45
–35
–30
650 750 850 950
55682 G11
1050 1150 1250
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
fBB = 100kHz
RF FREQUENCY (MHz)
550
–40
S11 (dB)
–20
–30
–10
0
650 750 850 950
55682 G12
1050 1150 1250
LO PORT, EN = LOW
RF PORT,
EN = LOW
RF PORT,
EN = HIGH,
PLO = 0dBm
RF PORT, EN = HIGH, No LO
LO PORT,
EN = HIGH,
PLO = 10dBm
LO PORT, EN = HIGH,
PLO = 0dBm
LO INPUT POWER (dBm)
–16
–14
VOLTAGE GAIN (dB)
–10
–12
–8
–6
–4
55682 G15
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
–20 –16 –12 –8 –4 0 4 8
TYPICAL PERFOR A CE CHARACTERISTICS
UW
VCC = 5V, EN = High, TA = 25°C, fLO = 900MHz,
PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.54VDC, Baseband Input Frequency fBB = 2MHz, I&Q 90° shifted. fRF = fBB + fLO (upper
sideband selection). PRF, OUT = –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3)
Noise Floor vs RF Frequency
Image Rejection vs LO Frequency
LO and RF Port Return Loss
vs RF Frequency
Voltage Gain vs LO Power
Output IP3 vs LO Power
Image Rejection vs LO Input Power
LO Feedthrough to RF Output
vs LO Input Power
I AND Q BASEBAND VOLTAGE (VP–P, DIFF)
0
–80
HD2 (dBc), HD3 (dBc)
RF CW OUTPUT POWER (dBm)
–40
–60
–20
–10
1234
55682 G18
–50
–70
–30
–60
–20
–40
0
10
–30
–50
–10
5
HD2 = MAX POWER AT fLO + 2 • fBB OR fLO – 2 • fBB
HD3 = MAX POWER AT fLO + 3 • fBB OR fLO – 3 • fBB
RF
HD2 4.5V
5.5V
5V
HD3
5V 4.5V
RF CW Output Power, HD2 and
HD3 vs CW Baseband Voltage
and Supply Voltage
LO INPUT POWER (dBm)
–50
–48
LO FEEDTHROUGH (dBm)
–44
–46
–42
–40
–38
55682 G13
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
–20 –16 –12 –8 –4 0 4 8
LO INPUT POWER (dBm)
13
15
0IP3 (dBm)
19
17
21
23
25
55682 G16
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
–20 –16 –12 –8 –4 0 4 8
fBB, 1 = 2MHz
fBB, 2 = 2.1MHz
I AND Q BASEBAND VOLTAGE (VP–P, DIFF)
0
–80
HD2 (dBc), HD3 (dBc)
RF CW OUTPUT POWER (dBm)
–40
–60
–20
–10
1234
55682 G17
–50
–70
–30
–60
–20
–40
0
10
–30
–50
–10
5
HD2 = MAX POWER AT fLO + 2 • fBB OR fLO – 2 • fBB
HD3 = MAX POWER AT fLO + 3 • fBB OR fLO – 3 • fBB
–40°C
HD3
85°C
RF
–40°C85°C
HD2
25°C
–40°C
25°C
85°C
25°C
RF CW Output Power, HD2 and
HD3 vs CW Baseband Voltage
and Temperature
LT5568-2
6
55682f
I AND Q BASEBAND VOLTAGE (VP-P,DIFF)
0
–55
IMAGE REJECTION (dBc)
–50
–45
1 1.5 2 2.5
55682 G20
0.5 3
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
fBB = 100kHz
I AND Q BASEBAND VOLTAGE (VP–P, DIFF, EACH TONE)
0.1
–80
PRF,TONE (dBm), IM2 (dBc), IM3 (dBc)
–40
–60
–20
–10
1
55682 G21
–50
–70
–30
0
10
10
IM2 = POWER AT fLO + 4.1MHz
IM3 = MAX POWER AT fLO + 1.9MHz OR fLO + 2.2MHz
RF
IM3
IM2
85°C
–40°C
85°C
–40°C
–40°C
25°C
85°C
25°C
fBBI = 2MHz, 2.1MHz, 0°
fBBQ = 2MHz, 2.1MHz, 90°
25°C
I AND Q BASEBAND VOLTAGE (VP–P, DIFF, EACH TONE)
0.1
–80
PRF,TONE (dBm), IM2 (dBc), IM3 (dBc)
–40
–60
–20
–10
1
55682 G22
–50
–70
–30
0
10
10
IM2 = POWER AT fLO + 4.1MHz
IM3 = MAX POWER AT fLO + 1.9MHz OR fLO + 2.2MHz
IM3
IM2
fBBI = 2MHz, 2.1MHz, 0°
fBBQ = 2MHz, 2.1MHz, 90°
4.5V
4.5V
5V, 5.5V
5V
5V, 5.5V
4.5V
5.5V
RF
Image Rejection
vs CW Baseband Voltage
RF Two-Tone Power (Each Tone),
IM2 and IM3 vs Baseband Voltage
and Temperature
RF Two-Tone Power (Each Tone),
IM2 and IM3 vs Baseband Voltage
and Supply Voltage
TYPICAL PERFOR A CE CHARACTERISTICS
UW
VCC = 5V, EN = High, TA = 25°C, fLO = 900MHz,
PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.54VDC, Baseband Input Frequency fBB = 2MHz, I&Q 90° shifted. fRF = fBB + fLO (upper
sideband selection). PRF, OUT = –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3)
GAIN (dB)
–9
0
PERCENTAGE (%)
5
10
15
20
25
–7.5
55682 G23
–8.5 –6.5–7
–8 –6 –5.5
–40°C
25°C
85°C
NOISE FLOOR (dBm/Hz)
–160.4
PERCENTAGE (%)
–159.6
55682 G24
–160 –159.2 –158.8
–40°C
25°C
85°C
0
5
10
15
20
35
30
25
LO LEAKAGE (dBm)
< –54
0
PERCENTAGE (%)
10
20
30
35
5
15
25
40
–46
55682 G25
–50 –42 –38 –30–34
–40°C
25°C
85°C
IMAGE REJECTION (dBc)
< –70
0
PERCENTAGE (%)
10
20
5
15
25
–62
55682 G26
–66 –58 –54 –46–50
–40°C
25°C
85°C
Noise Floor Distribution
LO Leakage Distribution Image Rejection Distribution
Gain Distribution
I AND Q BASEBAND VOLTAGE (VP-P,DIFF)
0
–44
LO FEEDTHROUGH (dBm)
–40
–42
–38
–36
1324
55682 G19
5
5.5V, 25°C
4.5V, 25°C
5V, 85°C
5V, 25°C
5V, –40°C
LO Feedthrough to RF Output
vs CW Baseband Voltage
LT5568-2
7
55682f
EN (Pin 1): Enable Input. When the enable pin voltage is
higher than 1V, the IC is turned on. When the input voltage
is less than 0.5V, the IC is turned off.
GND (Pins 2, 4, 6, 9, 10, 12, 15): Ground. Pins 6, 9, 15
and 17 (exposed pad) are connected to each other inter-
nally. Pins 2 and 4 are connected to each other internally
and function as the ground return for the LO signal. Pins
10 and 12 are connected to each other internally and
function as the ground return for the on-chip RF balun.
For best RF performance, pins 2, 4, 6, 9, 10, 12, 15 and
the Exposed Pad 17 should be connected to the printed
circuit board ground plane.
LO (Pin 3): LO Input. The LO input is an AC-coupled single-
ended input with approximately 50Ω input impedance at
RF frequencies. Externally applied DC voltage should be
within the range –0.5V to VCC + 0.5V in order to avoid
turning on ESD protection diodes.
BBPQ, BBMQ (Pins 7, 5): Baseband Inputs for the Q-chan-
nel, each 50Ω input impedance. Internally biased at about
0.54V. Applied voltage must stay below 2.5V.
VCC (Pins 8, 13): Power Supply. Pins 8 and 13 are con-
nected to each other internally. It is recommended to use
0.1µF capacitors for decoupling to ground on each of
these pins.
RF (Pin 11): RF Output. The RF output is an AC-coupled
single-ended output with approximately 50Ω output im-
pedance at RF frequencies. Externally applied DC voltage
should be within the range –0.5V to VCC + 0.5V in order
to avoid turning on ESD protection diodes.
BBPI, BBMI (Pins 14, 16): Baseband Inputs for the
I-channel, each with 50Ω input impedance. Internally biased
at about 0.54V. Applied voltage must stay below 2.5V.
Exposed Pad (Pin 17): Ground. This pin must be soldered
to the printed circuit board ground plane.
PI FU CTIO S
UUU
LT5568-2
8
55682f
The LT5568-2 consists of I and Q input differential volt-
age-to-current converters, I and Q up-conversion mixers,
an RF output balun, an LO quadrature phase generator
and LO buffers.
Figure 1. Simplifi ed Circuit Schematic of the LT5568-2
(Only I-Half is Drawn)
External I and Q baseband signals are applied to the dif-
ferential baseband input pins, BBPI, BBMI, and BBPQ,
BBMQ. These voltage signals are converted to currents and
translated to RF frequency by means of double-balanced
up-converting mixers. The mixer outputs are combined
in an RF output balun, which also transforms the output
impedance to 50Ω. The center frequency of the resulting
RF signal is equal to the LO signal frequency. The LO input
drives a phase shifter which splits the LO signal into in-
phase and quadrature LO signals. These LO signals are then
applied to on-chip buffers which drive the up-conversion
mixers. Both the LO input and RF output are single-ended,
50Ω-matched and AC coupled.
Baseband Interface
The baseband inputs (BBPI, BBMI), (BBPQ, BBMQ) present
a differential input impedance of about 100Ω. At each of the
four baseband inputs, a fi rst-order lowpass fi lter using 25Ω
APPLICATIO S I FOR ATIO
WUUU
BLOCK DIAGRA
W
90°
0°
LT5568-2
V-I
V-I
BALUN
VCC
RF
LO
55682 BD
11
EN
1
396
GND
42
5
7
16
14
8 13
BBPI
BBMI
BBPQ
BBMQ
1715
GND
1210
RF
VCC = 5V
BBPI
BBMI
C
GND
LOMI LOPI
R4
FROM
Q
55682 F01
BALUN
CM
VREF = 540mV
R3
R1B
23Ω
R1A
25Ω
12pF
R2A
25Ω
R2B
23Ω
12pF
LT5568-2
LT5568-2
9
55682f
APPLICATIO S I FOR ATIO
WUUU
Figure 3. LT5568-2 GSM Baseband Interface with 3rd Order Lowpass Filter and Ground Referenced DAC (Only I-Channel is Shown)
Figure 2. DC Voltage Levels for a Generator Programmed at
0.27VDC for a 50Ω Load and the LT5568-2 as a Load
The baseband inputs should be driven differentially; other-
wise, the even-order distortion products will degrade the
overall linearity severely. Typically, a DAC will be the signal
source for the LT5568-2. Reconstruction fi lters should
be placed between the DAC output and the LT5568-2’s
baseband inputs. In Figure 3, a typical baseband interface
schematic for GSM is drawn. It shows a ground referenced
DAC output interface followed by a 3rd order active OpAmp
RC lowpass fi lter with a 400kHz cutoff frequency (–3dB).
The DAC in this example sources a current from 0mA to
20mA, with a voltage compliance range of at least 0V to
1V. This interface is DC coupled, which allows adjust-
ment of the DAC’s differential output current to minimize
the LO feedthrough. The voltage swing at the LT5568-2
baseband inputs is about 2VP-P,DIFF, which results in a
1.2dBm GSM RF output power at 900MHz with noise fl oor
of –154.3dBm/Hz at 6MHz offset (= –104.3dBm/100kHz).
The RMS EVM is about 0.6%. The LT1819, which houses
two LT1818s, can be used instead of U2 and U3. The total
current in the positive supply is about 157mA and the
current in the negative supply is about 40mA.
and 12pF to ground is incorporated (see Figure 1), which
limits the baseband bandwidth to approximately 330MHz
(–1dB point). The common mode voltage is about 0.54V
and is approximately constant over temperature.
It is important that the applied common mode voltage level
of the I and Q inputs is about 0.54V in order to properly
bias the LT5568-2. Some I/Q test generators allow setting
the common mode voltage independently. In this case, the
common mode voltage of those generators must be set
to 0.27V to match the LT5568-2 internal bias, because for
DC signals, there is no –6dB source-load voltage division
(see Figure 2).
55682 F02
48Ω50Ω
LT5568-2
GENERATOR
0.54VDC
0.54VDC
0.54VDC +
–
+
–
50Ω
50Ω
GENERATOR
0.54VDC
0.27VDC
+
–
RF =
1.2dBm,
GSM
VCC = 4.5 TO 5.25V
VCC
VSS
C
GND
GND
LOMI LOPI
FROM
U1
Q
R4
33Ω
16mA
55682 F03
LT5568-2
CM
VREF = 540mV
R3
33Ω
R5
53.6Ω
R1
45Ω
2
3
BBPI
BBMI
R2
45Ω
DAC
0mA to 20mA
0mA to 20mA
C3
1nF
BALUN
R7
200Ω
R9
249Ω
R6
53.6Ω
R8
200Ω
R10
249Ω
–
+
–
+
C1
1.2nF
GND
R13
499Ω
R11
249Ω
C4
1nF
4
6
7
U2
LT1818
0.54V
0.54V
0.54V
0.54V
0.54V
VCC
VSS
VSS = –2V to –5.25V
3
2
C2
1.2nF
C5
10nF
C6
10nF
R12
249Ω
4
6
7
U3
LT1818
R14
50Ω
R15
50Ω
LT5568-2
10
55682f
APPLICATIO S I FOR ATIO
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LO Section
The internal LO input amplifi er performs single-ended to
differential conversion of the LO input signal. Figure 4
shows the equivalent circuit schematic of the LO input.
Table 1. LO Port Input Impedance vs Frequency for EN = High
and PLO = 0dBm
Frequency Input Impedance S11
MHz ΩMag Angle
500 47.5 + j12.1 0.126 95.0
600 59.4 + j8.4 0.115 37.8
700 66.2 – j1.14 0.140 –3.41
800 67.2 – j13.4 0.185 –31.7
900 61.1 – j23.9 0.232 –53.2
1000 53.3 – j26.8 0.252 –68.7
1100 48.2 – j26.1 0.258 –79.4
1200 42.0 – j27.4 0.297 –90.0
If the part is in shutdown mode, the input impedance of
the LO port will be different. The LO input impedance for
EN = Low is given in Table 2.
Table 2. LO Port Input Impedance vs Frequency for EN = Low and
PLO = 0dBm
Frequency Input Impedance S11
MHz ΩMag Angle
500 33.6 + j41.3 0.477 85.4
600 59.8 + j69.1 0.539 49.8
700 140 + j89.8 0.606 19.6
800 225 – j62.6 0.659 –6.8
900 92.9 – j128 0.704 –29.6
1000 39.8 – j95.9 0.735 –45.5
1100 22.8 – j72.7 0.755 –65.6
1200 16.0 – j57.3 0.763 –79.7
RF Section
After up-conversion, the RF outputs of the I and Q mixers are
combined. An on-chip balun performs internal differential
to single-ended output conversion, while transforming the
output signal impedance to 50Ω. Table 3 shows the RF
port output impedance vs frequency.
Table 3. RF Port Output Impedance vs Frequency for EN = High
and PLO = 0dBm
Frequency Input Impedance S22
MHz ΩMag Angle
500 22.0 + j5.7 0.395 164.2
600 28.2 + j12.5 0.317 141.3
700 38.8 + j14.8 0.206 117.5
800 49.4 + j7.2 0.072 90.6
900 49.3 – j5.1 0.051 –94.7
1000 42.5 – j11.1 0.143 –117.0
1100 36.7 – j11.7 0.202 –130.7
1200 33.0 – j10.3 0.238 –141.6
LO
INPUT
20pF
51Ω
5568 F04
VCC
The internal, differential LO signal is then split into in-phase
and quadrature (90° phase shifted) signals that drive LO
buffer sections. These buffers drive the double balanced I
and Q mixers. The phase relationship between the LO input
and the internal in-phase LO and quadrature LO signals
is fi xed, and is independent of start-up conditions. The
internal phase shifters are designed to deliver accurate
quadrature signals. For LO frequencies signifi cantly be-
low 650MHz or above 1.25GHz, however, the quadrature
accuracy will diminish, causing the image rejection to
degrade. The LO pin input impedance is about 50Ω, and
the recommended LO input power is 0dBm. For lower
LO input power, the gain, OIP2, OIP3 and noise fl oor at
PRF = 4dBm will degrade, especially for PLO below –2dBm
and at TA = 85°C. For high LO input power (e.g., +5dBm),
the image rejection will degrade with no improvement in
linearity or gain. Harmonics present on the LO signal can
degrade the image rejection because they can introduce a
small excess phase shift in the internal phase splitter. For
the second (at 1.8GHz) and third harmonics (at 2.7GHz) at
–20dBc, the resulting signal at the image frequency is about
–61dBc or lower, corresponding to an excess phase shift
of much less than 1 degree. For the second and third LO
harmonics at –10dBc, the introduced signal at the image
frequency is about –51dBc. Higher harmonics than the third
will have less impact. The LO return loss typically will be
better than 11dB over the 700MHz to 1.05GHz range. Table
1 shows the LO port input impedance vs frequency.
Figure 4. Equivalent Circuit Schematic of the LO Input
LT5568-2
11
55682f
APPLICATIO S I FOR ATIO
WUUU
The RF output S22 with no LO power applied is given in
Table 4.
Table 4. RF Port Output Impedance vs Frequency for EN = High
and No LO Power Applied
Frequency Input Impedance S22
MHz ΩMag Angle
500 22.7 + j5.6 0.381 164.0
600 29.7 + j11.6 0.290 142.0
700 40.5 + j11.6 0.164 121.9
800 47.3 + j2.2 0.037 139.6
900 44.1 – j6.7 0.094 –126.9
1000 38.2 – j9.8 0.171 –133.9
1100 34.0 – j9.4 0.218 –143.1
1200 31.5 – j7.8 0.245 –151.6
For EN = Low the S22 is given in Table 5.
Table 5. RF Port Output Impedance vs Frequency for EN = Low
Frequency Input Impedance S22
MHz ΩMag Angle
500 21.2 + j5.4 0.409 164.9
600 26.6 + j12.5 0.340 142.5
700 36.6 + j16.6 0.241 118.1
800 49.2 + j11.6 0.116 87.4
900 52.9 – j2.0 0.034 –33.1
1000 46.4 – j11.2 0.121 –101.1
1100 39.3 – j13.2 0.188 –120.6
1200 34.4 – j12.1 0.231 –133.8
Note that an ESD diode is connected internally from the
RF output to ground (see Figure 5). For strong output
RF signal levels (higher than 3dBm), this ESD diode can
degrade the linearity performance if the 50Ω termination
impedance is connected directly to ground. To prevent this,
a coupling capacitor can be inserted in the RF output line.
This is strongly recommended during a 1dB compression
measurement.
Enable Interface
Figure 6 shows a simplifi ed schematic of the EN pin
interface. The voltage necessary to turn on the LT5568-2
is 1V. To disable (shut down) the chip, the enable voltage
must be below 0.5V. If the EN pin is not connected, the
chip is disabled. This EN = Low condition is assured by
the 75k on-chip pull-down resistor. It is important that
the voltage at the EN pin does not exceed VCC by more
than 0.5V. If this should occur, the supply current could
be sourced through the EN pin ESD protection diodes,
which are not designed to carry the full supply current,
and damage may result.
Figure 5. Equivalent Circuit Schematic of the RF Output Figure 6. EN Pin Interface
75k
55682 F06
VCC
25k
EN
21pF
1pF7nH 51Ω
55682 F05
VCC
RF
OUTPUT
LT5568-2
12
55682f
Evaluation Board
Figure 7 shows the evaluation board schematic. A good
ground connection is required for the exposed pad. If this
is not done properly, the RF performance will degrade. Ad-
ditionally, the exposed pad provides heat sinking for the part
and minimizes the possibility of the chip overheating.
R1 (optional) limits the EN pin current in the event that
the EN pin is pulled high while the VCC inputs are low. In
Figures 8 and 9 the silk screens and the PCB board layout
are shown.
Figure 8. Component Side of Evaluation Board
Figure 9. Bottom Side of Evaluation Board
APPLICATIO S I FOR ATIO
WUUU
Figure 7. Evaluation Circuit Schematic
BBPIBBMI
J1
16 15 14 13
VCC
VCC EN
9
10
11
12
4
3
2
1
5678
55682 F07
17
BBMQ
BBPQ
BOARD NUMBER: DC1178A
C1
100nF J6
RF
OUT
J3
LO
IN
J4
GND
J5
C2
100nF
J2
BBMI
LT5568-2
BBPI VCC
BBMQ GND
GND
BBPQ VCC
GND
GND
RF
GND
GND
LO
GND
EN
GND
100Ω
R1
55682 F09
LT5568-2
13
55682f
RF OUTPUT POWER PER CARRIER (dBm)
–30
ACPR, AltCPR (dBc)
NOISE FLOOR AT 30MHz
OFFSET (dBm/Hz)
–70
–60
–10
55682 F11
–80
–90 –25 –20 –15 –5
–50
–145
–135
–155
–165
–125
DOWNLINK TEST MODEL 64 DPCH
1-CH. NOISE
3-CH. NOISE
1-CH. AltCPR
1-CH.
ACPR
3-CH. ACPR
3-CH. AltCPR
RF FREQUENCY (MHz)
896.25
POWER IN 30kHz BW (dBm)
–70
–50
–30
902.25
55682 F12
–90
–110
–80
–60
–40
–100
–120
–130 897.75 899.25 900.75 903.75
SPECTRUM ANALYSER NOISE FLOOR
UNCORRECTED
SPECTRUM
CORRECTED
SPECTRUM
DOWNLINK TEST
MODEL 64 DPCH
RF FREQUENCY (MHz)
894
POWER IN 30kHz BW (dBm)
–70
–50
–30
902 904
55682 F13
–90
–110
–80
–60
–40
–100
–120
–130 896 898 900 906
CORRECTED
SPECTRUM
UNCORRECTED
SPECTRUM
DOWNLINK
TEST
MODEL 64
DPCH
SPECTRUM ANALYSER
NOISE FLOOR
APPLICATIO S I FOR ATIO
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Application Measurements
The LT5568-2 is recommended for base-station applica-
tions using various modulation formats. Figure 10 shows a
typical application. Figure 11 shows the ACPR performance
for CDMA2000 using 1- and 3-carrier modulation. Figures
12 and 13 illustrate the 1- and 3-carrier CDMA2000 RF
spectrum. To calculate ACPR, a correction is made for the
spectrum analyzer noise fl oor. If the output power is high,
the ACPR will be limited by the linearity performance of the
part. If the output power is low, the ACPR will be limited
by the noise performance of the part. In the middle, an
optimum ACPR is observed.
Because of the LT5568-2’s very high dynamic range, the
test equipment can limit the accuracy of the ACPR mea-
surement. See Application Note 99. Consult the factory
for advice on the ACPR measurement, if needed.
The ACPR performance is sensitive to the amplitude match
of the BBPI and BBMI (or BBPQ and BBMQ) inputs. This
is because a difference in AC current amplitude will give
rise to a difference in amplitude between the even-order
harmonic products generated in the internal V-I converter.
As a result, they will not cancel out entirely. Therefore, it
is important to keep the currents in those pins exactly
Figure 10. 850MHz to 965MHz Direct
Conversion Transmitter Application
90°
0°
LT5568-2
BASEBAND
GENERATOR
PA
VCO/SYNTHESIZER
EN
2, 4, 6, 9, 10, 12, 15, 17
5V
V-I
V-I
I-CHANNEL
Q-CHANNEL BALUN
14
16
1
7
5
8, 13
VCC
11
355682 F10
I-DAC
Q-DAC
RF = 850MHz
TO 965MHz
100nF
x2
Figure 12. 1-Carrier CDMA2000 Spectrum Figure 13. 3-Carrier CDMA2000 Spectrum
Figure 11. ACPR, AltCPR and Noise
CDMA2000 Modulation
LT5568-2
14
55682f
TEMPERATURE (°C)
–40 –20
–90
LO FEEDTHROUGH (dBm), IR (dBc)
–70
–50
040 80
55682 F14
–80
–60
20 60
EN = High
VCC = 5V
fBBI = 2MHz, 0°
fBBQ = 2MHz, 90°
fLO = 900MHz
fRF = fBB + fLO
PLO = 0dBm
IMAGE REJECTION
LO FEED-
THROUGH
CALIBRATED WITH PRF = –10dBm
I AND Q BASEBAND VOLTAGE (VP-P, DIFF)
0
PRF (dBm), LOFT (dBm), IR (dBc)
–30
–10
10
4
55682 F15
–50
–70
–40
–20
0
–60
–80
–90 1235
fBBI = 2MHz, 0°
fBBQ = 2MHz, 90°
VCC = 5V
EN = High
fLO = 900MHz
fRF = fBB + fLO
PLO = 0dBm
–40°C
–40°C
–40°C
85°C
85°C
85°CLOFT
IR
PRF
25°C
25°C
25°C
APPLICATIO S I FOR ATIO
WUUU
the same (but of opposite sign). The current will enter
the LT5568-2’s common-base stage, and will fl ow to the
mixer upper switches. This can be seen in Figure 1 where
the internal circuit of the LT5568-2 is drawn.
After calibration when the temperature changes, the LO
feedthrough and the image rejection performance will
change. This is illustrated in Figure 14. The LO feedthrough
and image rejection can also change as a function of the
baseband drive level, as is depicted in Figure 15. In Figure
16 the GSM EVM and noise performance vs RF output
power is drawn.
Figure 15. LO Feedthrough and Image Rejection
vs Baseband Drive Voltage after Calibration at 25°C
Figure 14. LO Feedthrough and Image Rejection
vs Temperature after Calibration at 25°C
Figure 16. GSM EVM and Noise vs RF Output Power at 900MHz
GSM RF OUTPUT POWER (dBm)
–10
0
EVM (%RMS)
NOISE FLOOR AT 6MHz
OFFSET (dBc/100kHz)
1
3
4
5
–6 –2 0
2
–106
–104
–100
–98
–96
–102
–8 –4 246
55682 F16
EVM
NOISE
LT5568-2
15
55682f
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.
PACKAGE DESCRIPTIO
U
UF Package
16-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1692)
4.00 ± 0.10
(4 SIDES)
NOTE:
1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGC)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
PIN 1
TOP MARK
(NOTE 6)
0.55 ± 0.20
1615
1
2
BOTTOM VIEW—EXPOSED PAD
2.15 ± 0.10
(4-SIDES)
0.75 ± 0.05 R = 0.115
TYP
0.30 ± 0.05
0.65 BSC
0.200 REF
0.00 – 0.05
(UF16) QFN 10-04
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
0.72 ±0.05
0.30 ±0.05
0.65 BSC
2.15 ± 0.05
(4 SIDES)
2.90 ± 0.05
4.35 ± 0.05
PACKAGE OUTLINE
PIN 1 NOTCH R = 0.20 TYP
OR 0.35 × 45° CHAMFER
LT5568-2
16
55682f
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2007
LT 0307 • PRINTED IN USA
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
Infrastructure
LT5514 Ultralow Distortion, IF Amplifi er/ADC Driver with
Digitally Controlled Gain
850MHz Bandwidth, 47dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Range
LT5515 1.5GHz to 2.5GHz Direct Conversion Quadrature
Demodulator
20dBm IIP3, Integrated LO Quadrature Generator
LT5516 0.8GHz to 1.5GHz Direct Conversion Quadrature
Demodulator
21.5dBm IIP3, Integrated LO Quadrature Generator
LT5517 40MHz to 900MHz Quadrature Demodulator 21dBm IIP3, Integrated LO Quadrature Generator
LT5518 1.5GHz to 2.4GHz High Linearity Direct
Quadrature Modulator
22.8dBm OIP3 at 2GHz, –158.2dBm/Hz Noise Floor, 50Ω Single-Ended LO and RF
Ports, 4-Ch W-CDMA ACPR = –64dBc at 2.14GHz
LT5519 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 1.3GHz to 2.3GHz High Linearity Upconverting
Mixer
15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with 50Ω Matching,
Single-Ended LO and RF Ports Operation
LT5521 10MHz to 3700MHz High Linearity Upconverting
Mixer
24.2dBm IIP3 at 1.95GHz, NF = 12.5dB, 3.15V to 5.25V Supply, Single-Ended LO
Port Operation
LT5522 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
LT5525 High Linearity, Low Power Downconverting Mixer Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz, ICC = 28mA
LT5526 High Linearity, Low Power Downconverting Mixer 3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB, ICC = 28mA,
–65dBm LO-RF Leakage
LT5527 400MHz to 3.7GHz High Signal Level
Downconverting Mixer
IIP3 = 23.5dBm and NF = 12.5dB at 1900MHz, 4.5V to 5.25V Supply, ICC = 78mA
LT5528 1.5GHz to 2.4GHz High Linearity Direct
Quadrature Modulator
21.8dBm OIP3 at 2GHz, –159.3dBm/Hz Noise Floor, 50Ω, 0.5VDC Baseband Interface,
4-Ch W-CDMA ACPR = –66dBc at 2.14GHz
LT5557 400MHz to 3.8GHz, 3.3V, Very High Linearity
Downconverting Mixer
IIP3 = 24.7dBm at 1.9GHz, 23.5dBm at 3.5GHz, Conversion Gain = 2.9dB at 1.9GHz,
3.3V at 82mA, –3dB LO Drive
LT5558 600MHz to 1100MHz High Linearity Direct
Quadrature Modulator
22.4dBm OIP3 at 900MHz, –158dBm/Hz Noise Floor, 3kΩ, 2.1VDC Baseband
Interface, 3-Ch CDMA2000 ACPR = –70.4dBc at 900MHz
LT5560 Ultra-Low Power Active Mixer 10mA Supply Current, 10dBm IIP3, 10dB NF, Usable as Up- or Down-Converter
LT5568 700MHz to 1050MHz High Linearity Direct
Quadrature Modulator
22.9dBm OIP3 at 850MHz, –160.3dBm/Hz Noise Floor, 50Ω, 0.5VDC Baseband
Interface, 3-Ch CDMA2000 ACPR = –71.4dBc at 850MHz
LT5572 1.5GHz to 2.5GHz High Linearity Direct
Quadrature Modulator
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
LT5575 800MHz to 2.7GHz High Linearity Direct
Conversion Quadrature Demodulator
28dBm IIP3 and 13.2dBm P1dB at 900MHz, 60dBm IIP2 and 12.7dB NF
at 1900MHz
RF Power Detectors
LTC
®
5505 RF Power Detectors with >40dB Dynamic Range 300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply
LTC5507 100kHz to 1000MHz RF Power Detector 100kHz to 1GHz, Temperature Compensated, 2.7V to 6V Supply
LTC5508 300MHz to 7GHz RF Power Detector 44dB Dynamic Range, Temperature Compensated, SC70 Package
LTC5509 300MHz to 3GHz RF Power Detector 36dB Dynamic Range, Low Power Consumption, SC70 Package
LTC5530 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Shutdown, Adjustable Gain
LTC5531 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Shutdown, Adjustable Offset
LTC5532 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Adjustable Gain and Offset
LT5534 50MHz to 3GHz Log RF Power Detector with
60dB Dynamic Range
±1dB Output Variation over Temperature, 38ns Response Time
LTC5536 Precision 600MHz to 7GHz RF Detector with Fast
Comparator
25ns Response Time, Comparator Reference Input, Latch Enable Input, –26dBm to
+12dBm Input Range
LT5537 Wide Dynamic Range Log RF/IF Detector Low Frequency to 800MHz, 83dB Dynamic Range, 2.7V to 5.25V Supply
