Intersil Corporation HFA3761 Datasheet
TM
HFA3761
Data Sheet July 1999 File Number 4236.4
400MHz AGC and Quadrature IF
Demodulator
The HFA3761 is a highly integrated
baseband converter for quadrature
demodulation applications. The
HFA3761 400MHz AGC and
quadrature IF demodulator is one of the
seven chips in the PRISM® full duplex chip set (see Typical
Application Diagram). It features all the necessary blocks for
baseband demodulation of I and Q signals. It has a two
stage integrated AGC IF amplifier with 82dB of voltage gain
and 76dB of gain control range. 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 tunable
over a ±20% frequency range via one external resistor. To
achieve broadband operation, the Local Oscillator
frequency input is required to be twice the desired
frequency of 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.
Features
• Integrates all IF and AGC Receive Functions
• Broad Frequency Range . . . . . . . . . . 10MHz to 400MHz
• I/Q Amplitude and Phase Balance . . . . 0.2dB, 2 Degrees
• 5th Order Programmable
Low Pass Filter. . . . . . . . . . . . . . . . . 2.2MHz to 17.6MHz
• 400MHz AGC Gain Strip . . . . . . . . . . . . . . . . . . . . . 82dB
• AGC Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75dB
• Low LO Drive Level . . . . . . . . . . . . . . . . . . . . . . . -15dBm
• Fast AGC Switching . . . . . . . . . . . . . . . . . . . . . . . . . . 1µs
• Power Management/Standby Mode
• Single Supply 2.7V to 5.5V Operation
Applications
• Wireless Local Loop
• Wireless Local Area Networks
• PCMCIA Wireless Transceivers
• ISM Systems
Ordering Information
TEMP.
PART NUMBER
HFA3761IN -40 to 85 80 Ld TQFP Q80.14x14
RANGE (oC) PACKAGE PKG. NO.
Simplified Block Diagram
AGC1_OUT
AGC2_IN
AGC_SEL
AGC1_IN
AGC1_V
AGC
AGC2_V
AGC
DEMOD_LO_IN
DEMOD_LO_OUT
LO_GND
AGC2_OUT
DEMOD_IF_IN
÷2
0o/90
• CDMA Radios
• PCS/Wireless PBX
LPF_TUNE_1
LPF_RX_I
LPF_RX_Q
DEMOD_RX_I
DEMOD_RX_Q
I
Q
2V
o
REF
2V REF
LPF_SEL0
LPF_TUNE_0
LPF_RXI_OUT
LPF_RXQ _OUT
LPF_SEL1
4-1
1-888-INTERSIL or 321-724-7143 | Intersil and Design is a trademark of Intersil Corporation. | Copyright © Intersil Corporation 2000
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
PRISM® is a registered trademark of Intersil Corporation. PRISM logo is a trademark of Intersil Corporation.
Pinout
HFA3761
80 LEAD TQFP
TOP VIEW
AGC1_BYP+
AGC1_IN+
GND
AGC_SEL
AGC1_IN-
AGC1_BYP-
GND
GND
LPF_V
CC
2V REF
LPF_BYP
NC
LPF_RXI_OUT
LPF_RXQ_OUT
NC
LPF_SEL1
LPF_SEL0
LPF_TUNE1
LPF_TUNE0
GND
CC
AGC
GND
AGC1_V
AGC1_V
80
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
2122 2324 2526 27 2829 3031 323334 3536
NC
GND
LPF_RX_PE
AGC1_PE
AGC1_OUT-
AGC1_OUT+
NCNCNC
CC
GND
GND
AGC1_V
LPF_RXI-
LPF_RXQ-
LPF_RXQ+
GND
GND
GND
GND
GND
LPF_RXI+
AGC2_BYP-
GND
GND
GND
AGC2_IN-
64656667686970717273747576777879
3738 3940
NCNCNC
DEMOD_RXI-
DEMOD_RXI+
DEMOD_RXQ-
DEMOD_RXQ+
AGC2_IN+
GND
6362 61
AGC2_BYP+
AGC2_V
60
GND
59
AGC2_V
58
AGC2_PE
57
AGC2_OUT+
56
AGC2_OUT-
55
54
AGC2_V
53
GND
GND
52
GND
51
LO_GND
50
DEMOD_IFIN-
49
DEMOD_IFIN+
48
DEMOD_V
47
46
LO_OUT
45
DEMOD_V
44
LO_IN
43
DEMOD_RX_PE
DEMOD_V
42
41
GND
NC
AGC
CC
CC
CC
CC
CC
Typical Full Duplex Application Diagram
PRISM FULL DUPLEX CHIP SET
HFA3424/21
(File #4131)
D
U
P
L
E
X
E
R
LNA BPF
HFA3925
(File #4132)
PA BPF
HFA3524
(File #4062)
HFA3524
(File #4062)
For additional information on the PRISM Full Duplex Radio
Chip Set, call (321) 724-7800 to access Intersil’ AnswerFAX
system. When prompted, key in the four-digit document
number (File #) of the data sheets you wish to receive.
HFA3661
(File #4240)
LNA
SYNTHESIZER
SYNTHESIZER
AGC
HFA3663 (File #4241)
HFA3664 (File #4242)
RF/IF
CONVERTER
RF LO1
RF LO2
IF/RF
CONVERTER
FILTER
IF LO1
IF LO2
HFA3761 (File #4236)
IF AGC
AGC
QMODEM
LPF
LPF
HFA3763
(File #4237)
LPF
QMODEM
LPF
A/D
BASEBAND
D/A
OPTIONAL WHEN IN
ANALOG MODE
PRISM FULL DUPLEX RADIO
CHIP SET, FILE #4238
The four-digit file numbers are shown in Typical Application
Diagram, and correspond to the appropriate circuit.
4-2
Block Diagram
HFA3761
DEMOD_RX Q -
DEMOD_RX Q +
DEMOD_RX I -
DEMOD_RX I +
DEMOD_IF_IN +
DEMOD_IF_IN -
AGC2_OUT -
AGC2_OUT +
AGC2_PE
AGC1_PE
AGC2_IN+
AGC2_IN-
AGC1_OUT -
AGC1_OUT +
LPF_TUNE0
LPF_TUNE1
LPF_RX PE
LPF_RX I -
LPF_RX I +
LPF_RX Q +
LPF_RX Q -
DEMOD_RX PE
DOWN CONV
LPF_RXI_OUT
IF
LPF_RXQ_OUT
LPF_SEL1
LPF_SEL0
o
/90
o
0
2V REF
÷2
OPTIONAL FILTER
NOTE: VCC, GND and Bypass capacitors not shown.
4-3
AGC_SEL
SAW
IF
IF
AGC1_IN+
IN
AGC
AGC1_IN-
AGC1_V
AGC
AGC2_V
AGC CTRL
LO_GND
(2XLO)
DEMOD_LO_IN
50Ω
DEMOD_LO_OUT
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