NOISE FLOOR AT 6MHz
OFFSET (dBc/100kHz)
LT5568-2
GSM/EDGE Optimized,
High Linearity Direct
Quadrature Modulator
FEATURES DESCRIPTIO
Optimized Image Rejection for 850MHz to 965MHz The LT 5568-2 is a direct I/Q modulator designed for high
High OIP3: +22.9dBm at 900MHz performance wireless applications, including wireless
Low Output Noise Floor at 5MHz Offset: infrastructure. It allows direct modulation of an RF signal
No RF: 159.4dBm/Hz using differential baseband I and Q signals. It supports
P = 4dBm: 153dBm/Hz GSM, EDGE, CDMA, CDMA2000 and other systems that
OUT
Integrated LO Buffer and LO Quadrature Phase operate in the 850MHz to 965MHz band. It may be con g-
Generator ured as an image reject upconverting mixer, by applying
50 AC-Coupled Single-Ended LO and RF Ports 90 phase-shifted signals to the I and Q inputs. The I/Q
50 DC Interface to Baseband Inputs baseband inputs consist of voltage-to-current converters
Low Carrier Leakage: 43dBm at 900MHz that in turn drive double-balanced mixers. The outputs of
High Image Rejection: 52dBc at 900MHz these mixers are summed and applied to an on-chip RF
16-Lead 4mm 4mm QFN Package transformer, which converts the differential mixer signals
to a 50 single-ended output. The four balanced I and Q
U
baseband input ports are intended for DC coupling from a
APPLICATIO S
source with a common mode voltage level of about 0.5V.
The LO path consists of an LO buffer with single-ended
Infrastructure Tx for GSM/Cellular Bands
input, and precision quadrature generators that produce
Image Reject Up-Converters for Cellular Bands
the LO drive for the mixers. The supply voltage range is
Low-Noise Variable Phase-Shifter for 700MHz to
4.5V to 5.25V.
1050MHz Local Oscillator Signals
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
RFID Reader
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
GSM EVM and Noise
850MHz to 965MHz Direct Conversion Transmitter Application vs RF Output Power at 900MHz
5
96
5V
V
CC
100nF
LT5568-2
x 2
RF = 850MHz
4
98
TO 965MHz
I-DAC V-I
I-CHANNEL
3 100
PA
NOISE
0
EN
90
BALUN
2 102
Q-CHANNEL
Q-DAC
V-I EVM
1 104
55682 TA01
BASEBAND
0 106
GENERATOR
10 8 6 4 2 0 2 4 6
VCO/SYNTHESIZER
GSM RF OUTPUT POWER (dBm)
55682 TA02
55682f
1
EVM (%RMS)
U
ULT5568-2
ABSOLUTE AXI U RATI GS PIN CONFIGURATION
(Note 1)
TOP VIEW
Supply Voltage .........................................................5.5V
Common Mode Level of BBPI, BBMI and
16 15 14 13
BBPQ, BBMQ .......................................................2.5V
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
16-LEAD (4mm 4mm) PLASTIC QFN
CAUTION: This part is sensitive to ESD. It is very
T = 125C, = 37C/W
JMAX JA
important that proper ESD precautions be observed
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
when handling the LT5568-2.
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 40C to 85C
Consult LTC Marketing for parts speci ed with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based nish parts.
For more information on lead free part marking, go to: