LT5521 Datasheet, PDF (1/16 Pages) Linear Technology – Very High Linearity Active Mixer

FEATURES
s _{Wideband Output Frequency Range to 3.7GHz}
s _{+24.2dBm IIP3 at 1.95GHz RF Output}
s _{Low LO Leakage: –42dBm}
s _{Integrated LO Buffer: Low LO Drive Level}
s _{Single-Ended LO Drive}
s _{Wide Single Supply Range: 3.15V to 5.25V}
s _{Double-Balanced Active Mixer}
s _{Shutdown Function}
s _{16-Lead (4mm × 4mm) QFN Package}
U
APPLICATIO S
s _{Cellular, W-CDMA, PHS and UMTS Infrastructure}
s _{Cable Downlink Infrastructure}
s _{Wireless Infrastructure}
s _{Fixed Wireless Access Equipment}
s _{High Linearity Mixer Applications}
LT5521
Very High Linearity
Active Mixer
DESCRIPTIO
The LT^®5521 is a very high linearity mixer optimized for
low distortion and low LO leakage applications. The chip
includes a high speed LO buffer with single-ended input
and a double-balanced active mixer. The LT5521 requires
only –5dBm LO input power to achieve excellent distor-
tion and noise performance, while reducing external drive
circuit requirements. The LO buffer is internally 50Ω
matched for wideband operation.
With a 250MHz input, a 1.7GHz LO and a 1.95GHz output
frequency, the mixer has a typical IIP3 of +24.2dBm,
–0.5dB conversion gain and a 12.5dB noise figure.
The LT5521 offers exceptional LO-RF isolation, greatly
reducing the need for output filtering to meet LO suppres-
sion requirements.
The device is designed to work over a supply voltage range
from 3.15V to 5.25V.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
BPF 1nF
IF
INPUT
1:1
10pF
1nF
110Ω
IN⁺
6.8pF
IN^–
LO INPUT
–5dBm
6.8pF
LO _GND
OUT⁺
OUT^–
110Ω
BIAS
EN VCC VCC VCC
2.7nH
4:1
2.7nH
1nF
5V DC
1µF
5521 TA01
82pF
BPF
PA
82pF
RF
OUTPUT
Fundamental, 3rd Order
Intermodulation Distortion
vs Input Power
20
0
P_FUND
–20
–40
IM3
–60
–80
–100
–14 –12 –10 –8 –6 –4 –2
P_IN (dBm)
f_IF = 250MHz
f_LO = 1.7GHz
f_RF = 1.95GHz
P_LO = –5dBm
T_A = 25°C
02 4 6
5521 TA02
5521f
1