
1
HFA3724
400MHz Quadrature IF
Modulator/Demodulator
The Intersil 2.4GHz PRISM chip set is a
highly integrated five-chip solution for RF
modems employing Direct Sequence
Spread Spectrum (DSSS) signaling. The
HFA3724 400MHz Quadrature IF
Modulator/Demodulator is one of the five chips in the PRISM
chip set (see the Typical Application Diagram).
The HFA3724 is a highly integrated baseband converter for
quadrature modulation applications. It features all the necessary
blocks for baseband modulation and demodulation of I and Q
signals. It has a two stage integrated limiting IF amplifier with 84db
of gain with a built in Receive Signal Strength Indicator (RSSI).
Baseband antialiasing and shaping filters are integrated in the
design. Four filter bandwidths are programmable via a two bit
digital control interface. In addition, these filters are continuously
tunableovera
±
20% frequencyrangevia oneexternalresistor.The
modulator channel receives digital I and Q data for processing. To
achieve broadband operation, the Local Oscillator frequency input
is required to be twice the desired frequency of
modulation/demodulation. A selectable buffered divide by 2 LO
output and a stable reference voltage are provided for convenience
of the user. The device is housed in a thin 80 lead TQFP package
well suited for PCMCIA board applications.
Ordering Information
Features
Integrates all IF Transmit and Receive Functions
Broad Frequency Range . . . . . . . . . . .10MHz to 400MHz
I/Q Amplitude and Phase Balance . . . . . . . . . . . 0.2dB, 2
o
5th Order Programmable
Low Pass Filter. . . . . . . . . . . . . . . . . . .2.2MHz - 17.6MHz
400MHz Limiting IF Gain Strip with RSSI. . . . . . . . . .84dB
Low LO Drive Level . . . . . . . . . . . . . . . . . . . . . . . -15dBm
Fast Transmit-Receive Switching . . . . . . . . . . . . . . . . .1
μ
s
Power Management/Standby Mode
Single Supply 2.7V to 5.5V Operation
Applications
Systems Targeting IEEE 802.11 Standard
TDD Quadrature-Modulated Communication Systems
Wireless Local Area Networks
PCMCIA Wireless Transceivers
ISM Systems
TDMA Packet Protocol Radios
PCS/Wireless PBX
Wireless Local Loop
Simplified Block Diagram
PART NUMBER
HFA3724IN
HFA3724IN96
TEMP. RANGE
(
o
C)
-40 to 85
-40 to 85
PACKAGE
80 Ld TQFP
Tape and Reel
PKG. NO.
Q80.14x14
0
o
/90
o
LIM1_IN
MOD_LO_IN
MOD_TX_IF_OUT
L
L
LPF_RXQ _OUT
RSSI2
MOD_LO_OUT
LO_GND
RSSI1
L
L
L
L
M
M
L
M
M
L
M
÷
2
L
L
LPF_TXI_IN
LPF_TXQ_IN
2V
REF
L
LPF_RXI_OUT
I
Q
IF
IF
∑
M
U
X
M
U
X
Data Sheet
November 1999
File Number
4067.7
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
|
Copyright
Intersil Corporation 1999
PRISM is a registered trademark of Intersil Corporation. PRISM logo is a trademark of Intersil Corporation.