NOISE FLOOR AT 30MHz OFFSET (dBm/Hz)
LT5571
620MHz 1100MHz High
Linearity Direct Quadrature
Modulator
FEATURES DESCRIPTION
Direct Conversion from Baseband to RF
The LT 5571 is a direct I/Q modulator designed for high
High Output: 4.2dB Conversion Gain
performance wireless applications, including wireless
High OIP3: 21.7dBm at 900MHz
infrastructure. It allows direct modulation of an RF signal
Low Output Noise Floor at 20MHz Offset:
using differential baseband I and Q signals. It supports
No RF: 159dBm/Hz
RFID, GSM, EDGE, CDMA, CDMA2000, and other systems.
P = 4dBm: 153.3dBm/Hz
It may also be con gured as an image reject upconvert-
OUT
Low Carrier Leakage: 42dBm at 900MHz
ing mixer by applying 90 phase-shifted signals to the I
High Image Rejection: 53dBc at 900MHz
and Q inputs. The high impedance I/Q baseband inputs
3-Ch CDMA2000 ACPR: 70.4dBc at 900MHz
consist of voltage-to-current converters that in turn drive
Integrated LO Buffer and LO Quadrature Phase
double-balanced mixers. The outputs of these mixers are
Generator
summed and applied to an on-chip RF transformer, which
50 AC-Coupled Single-Ended LO and RF Ports
converts the differential mixer signals to a 50 single-
High Impedance DC Interface to Baseband Inputs
ended output. The four balanced I and Q baseband input
with 0.5V Common Mode Voltage
ports are intended for DC-coupling from a source with a
16-Lead QFN 4mm 4mm Package
common-mode voltage at 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
APPLICATIONS
mixers. The supply voltage range is 4.5V to 5.25V.
RFID Interrogators , LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
GSM, CDMA, CDMA2000 Transmitters
Point-to-Point Wireless Infrastructure Tx
Image Reject Up-Converters for Cellular Bands
Low-Noise Variable Phase-Shifter for 620MHz to
1100MHz Local Oscillator Signals
TYPICAL APPLICATION
CDMA2000 ACPR, AltCPR and Noise vs RF
Direct Conversion Transmitter Application
Output Power at 900MHz for 1 and 3 Carriers
40 110
5V
DOWNLINK TEST
100nF MODEL 64 DPCH
V LT5571
CC 2
RF = 620MHz
50 120
TO 1100MHz
I-DAC V-I 3-CH ACPR
1-CH
I-CH
3-CH AltCPR
PA 60 ACPR 130
0
EN
90
BALUN
70 140
Q-CH
1-CH NOISE
Q-DAC
V-I
80 150
1-CH AltCPR
BASEBAND 3-CH NOISE
5571 TA01a
GENERATOR
90 160
VCO/SYNTHESIZER 30 25 20 15 10 5 0
RF OUTPUT POWER PER CARRIER (dBm)
5571 TA01b
5571f
1
ACPR, AltCPR (dBc)LT5571
ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION
(Note 1)
TOP VIEW
Supply Voltage .........................................................5.5V
Common-Mode Level of BBPI, BBMI and
16 15 14 13
BBPQ, BBMQ .......................................................0.6V
EN 1 12 GND
Operating Ambient Temperature
GND 2 11 RF
17
(Note 2) ............................................... 40C to 85C
LO 3 10 GND
Storage Temperature Range ................... 65C to 125C
GND 4 9 GND
5 6 7 8
Voltage on any Pin
Not to Exceed ...................... 500mV to V + 500mV
CC
UF PACKAGE
Note: The baseband input pins should not be left oating.
16-LEAD (4mm 4mm) PLASTIC QFN
T = 125C, = 37C/W
JMAX JA
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER UF PART MARKING
LT5571EUF 5571
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: