LT5500 Datasheet, PDF (1/12 Pages) Linear Technology – 1.8GHz to 2.7GHz Receiver Front End

LT5500
1.8GHz to 2.7GHz
Receiver Front End
FEATURES
■ _{1.8V to 5.25V Supply}
■ _{Dual LNA Gain Setting: +13.5dB/–14dB at 2.5GHz}
■ _{Double-Balanced Mixer}
■ _{Internal LO Buffer}
■ _{LNA Input Internally Matched}
■ _{Low Supply Current: 23mA}
■ _{Low Shutdown Current: 2µA}
■ _{24-Lead Narrow SSOP Package}
U
APPLICATIO S
■ _{IEEE 802.11 and 802.11b DSSS and FHSS}
■ _{High Speed Wireless LAN}
■ _{Wireless Local Loop}
DESCRIPTIO
The LT^®5500 is a receiver front end IC designed for low
voltage operation. The chip contains a low noise amplifier
(LNA), a Mixer and an LO buffer. The IC is designed to
operate over a power supply voltage range from 1.8V to
5.25V.
The LNA can be set to either high gain or low gain mode.
At 2.5GHz, the high gain mode provides 13.5dB gain and
a noise figure (NF) of 4dB. The LNA in low gain mode
provides –14dB gain and an IIP3 of + 8dBm at 2.5GHz.
The mixer has 5dB of conversion gain and an IIP3 of
– 2.5dBm at 2.5GHz, with –10dBm LO input power.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
RF
INPUT
ENABLE
100pF
GAIN
SELECT
100pF
2V
RF INPUT
FILTER
EN
LT5500
GS
L4
LNA_IN
LNA_OUT
GND
LNA_GND
C4
LO^–
100pF
×2
L2
2V
1µF
1nF
IF OUTPUT
L7
LO^{+ C17 L3}
V_CC
100pF
×4
MIX_GND ^LO MIX_IN
L9
RF
IF
L5
IF⁺
IF^–
T2
8:1 _2V
••
100pF
5500 F01
LO INPUT
C23
INTERSTAGE
FILTER
Figure 1. 2.5GHz Receiver. Interstage Filter is Optional
LNA Gain (High Gain Mode)
and Mixer Conversion Gain
14.0 _{fRF = 2.5GHz}
6.0
13.9 TA = 25°C
5.8
13.8
5.6
13.7
5.4
13.6
5.2
13.5
5.0
13.4
4.8
13.3
4.6
13.2
4.4
13.1
4.2
13.0
4.0
1.5 2 2.5 3 3.5 4 4.5 5 5.5
V_CC (V)
5500 TA02
5500f
1