2-134
Typical Application Diagram
For additional information on the PRISM chip set, call
(407) 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.
Pin Descriptions
The four-digit file numbers are shown in the Typical
Application Diagram, and correspond to the appropriate
circuit.
QUAD IF MODULATOR
RFPA
HFA3925
(FILE# 4132)
HFA3724/6
(FILE# 4067)
DSSS BASEBAND PROCESSOR
D
C
HFA3860A
(FILE# 4488)
HFA3524
0
o
/90
o
VCO
A/D
A/D
MAC-PHY
INTERFACE
802.11
VCO
DUAL SYNTHESIZER
HFA3624
UP/DOWN
CONVERTER
(FILE# 4066)
A/D
(FILE# 4062)
M
U
X
M
U
X
DEMOD
MOD.
DE-
SPREAD
SPREAD
Q
I
HFA3424
(NOTE)
(FILE# 4131)
TYPICAL TRANSCEIVER APPLICATION CIRCUIT USING THE HFA3860A
NOTE: Required for systems targeting 802.11 specifications.
CCA
RXI
RXQ
RSSI
TXI
TXQ
÷
2
NAME
PIN
TYPE I/O
DESCRIPTION
V
DDA
(Analog)
10, 18, 20
Power
DC power supply 2.7V - 3.6V (Not Hardwired Together On Chip).
V
DD
(Digital)
7, 21, 29, 42
Power
DC power supply 2.7 - 3.6V
GND
(Analog)
11, 15, 19
Ground
DC power supply 2.7 - 3.6V, ground (Not Hardwired Together On Chip).
GND
(Digital)
6, 22, 31, 41
Ground
DC power supply 2.7 - 3.6V, ground.
V
REFN
V
REFP
I
IN
Q
IN
ANTSEL
17
I
“Negative” voltage reference for A/D’s (I and Q) [Relative to V
REFP
]
“Positive” voltage reference for A/D’s (I, Q and RSSI)
16
I
12
I
Analog input to the internal 3-bit A/D of the In-phase received data.
13
I
Analog input to the internal 3-bit A/D of the Quadrature received data.
26
O
The antenna select signal changes state as the receiver switches from antenna to antenna during the
acquisition process in the antenna diversity mode. This is a complement for ANTSEL (pin 27) for
differential drive of antenna switches.
ANTSEL
27
O
The antenna select signal changes state as the receiver switches from antenna to antenna during the
acquisition process in the antenna diversity mode. This is a complement for ANTSEL (pin 26) for
differential drive of antenna switches.
RSSI
14
I
Receive Signal Strength Indicator Analog input.
TX_PE
2
I
When active, the transmitter is configured to be operational, otherwise the transmitter is in standby mode.
TX_PEisaninputfromtheexternalMediaAccessController(MAC)ornetworkprocessortotheHFA3860A.
The rising edge of TX_PE will start the internal transmit state machine and the falling edge will initiate shut
down of the state machine. TX_PE envelopes the transmit data except for the last bit. The transmitter will
continue to run for 3 symbols after TX_PE goes inactive to allow the PA to shut down gracefully.
HFA3860A