LTC5584 Datasheet, PDF (1/32 Pages) –

Features
n _{I/Q Bandwidth of 530MHz or Higher}
n _{High IIP3: 31dBm at 450MHz, 28dBm at 900MHz}
n _{High IIP2: 70dBm at 450MHz, 65dBm at 900MHz}
n _{User Adjustable IIP2 to >80dBm}
n _{User Adjustable DC Offset Null}
n _{High Input P1dB: 13.1dBm at 900MHz}
n _{Image Rejection: 45dB at 900MHz}
n _{Noise Figure: 9.9dB at 450MHz}

10dB at 900MHz
n _{Conversion Gain: 5.4dB at 450MHz}

5.7dB at 900MHz
n _{Shutdown Mode}
n _{Operating Temperature Range (TC): –40°C to 105°C}
n _{24-Lead 4mm × 4mm QFN Package}
Applications
n _{LTE/W-CDMA/TD-SCDMA Base Station Receivers}
n _{Wideband DPD Receivers}
n _{Point-To-Point Broadband Radios}
n _{High Linearity Direct Conversion I/Q Receivers}
n _{Image Rejection Receivers}
LTC5584
30MHz to 1.4GHz IQ
Demodulator with IIP2 and
DC Offset Control
Description
The LTC^®5584 is a direct conversion quadrature demodu-
lator optimized for high linearity receiver applications in
the 30MHz to 1.4GHz frequency range. It is also usable
in the 10MHz to 30MHz and 1.4GHz to 2GHz ranges with
reduced performance. It is suitable for communications
receivers where an RF signal is directly converted into I
and Q baseband signals with bandwidth of 530MHz or
higher. The LTC5584 incorporates balanced I and Q mix-
ers, LO buffer amplifiers and a precision, high frequency
quadrature phase shifter. In addition, the LTC5584 provides
four analog control voltage interface pins for IIP2 and DC
offset correction, greatly simplifying system calibration.
The high linearity of the LTC5584 provides excellent spur-
free dynamic range for the receiver. This direct conversion
demodulator can eliminate the need for intermediate fre-
quency (IF) signal processing, as well as the corresponding
requirements for image filtering and IF filtering. These
I/Q outputs can interface directly to channel-select filters
(LPFs) or to baseband amplifiers.
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.
Typical Application
Direct Conversion Receiver with IIP2 and DC Offset Calibration
5V
BPF
LNA BPF _RF
INPUT
RF⁺
V_CC
RF^–
I^{+ LPF}
VGA
I^–
IP2 AND DC
OFFSET CAL
IP2 ADJUST
DC OFFSET
LO
LO INPUT
0°
LTC5584
90°
IP2 AND DC
OFFSET CAL
DC OFFSET
IP2 ADJUST
ENABLE
EN
Q^{+ LPF}
VGA
Q^–
A/D
D/A
D/A
D/A
D/A
A/D
5584 TA01a
IIP2 vs IP2I, IP2Q Trim Voltage
130
120
I, –40°C
I, 25°C
I, 85°C
Q, –40°C
Q, 25°C
f_RF = 450MHz
Q, 85°C
I, 105°C
Q, 105°C
110
100
90
80
70
60
50
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
IP2I, IP2Q (V)
5584 TA01b
5584f
1