3

Pin Descriptions

NAME

PIN

TYPE I/O

DESCRIPTION

31

Power

DC power supply 2.7V - 3.6V (Not Hard wired Together On Chip).

Power

DC power supply 2.7 - 3.6V.

GNDa

(Analog)

9, 15, 20,

25, 28,

Ground

DC power supply 2.7 - 3.6V, ground (Not Hard wired Together On Chip).

GNDd (Digital) 1, 7, 36, 43,

56

Ground

DC power supply 2.7 - 3.6V, ground.

16

I

Voltage reference for A/D’s and D/A’s.

21

I

Current reference for internal ADC and DAC devices. Requires a 12kΩ resistor to ground.

10/11

I

Analog input to the internal 6-bit A/D of the In-phase received data. Balanced differential 10+/11-.

13/14

I

Analog input to the internal 6-bit A/D of the Quadrature received data. Balanced differential 13+/14-.

ANTSEL

39

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 40) for

differential drive of antenna switches.

ANTSEL

40

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 39) for

differential drive of antenna switches.

RX_IF_DET

19

I

Analog input to the receive power A/D converter for AGC control.

RX_IF_AGC

34

O

Analog drive to the IF AGC control.

RX_RF_AGC

38

O

Drive to the RF AGC stage attenuator. CMOS digital.

TX_AGC_IN

18

I

Input to the transmit power A/D converter for transmit AGC control.

TX_IF_AGC

35

O

Analog drive to the transmit IF power control.

TX_PE

62

I

When active, the transmitter is configured to be operational, otherwise the transmitter is in standby

mode. TX_PE is an input from the external Media Access Controller (MAC) or network processor to

the HFA3861B. 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 4µs after TX_PE goes inactive to allow the PA to shut

down gracefully.

TXD

58

I

TXD is an input, used to transfer MAC Payload Data Unit (MPDU) data from the MAC or network

processor to the HFA3861B. The data is received serially with the LSB first. The data is clocked in the

HFA3861B at the rising edge of TXCLK.

TXCLK

55

O

TXCLK is a clock output used to receive the data on the TXD from the MAC or network processor to

the HFA3861B, synchronously. Transmit data on the TXD bus is clocked into the HFA3861B on the

rising edge. The clocking edge is also programmable to be on either phase of the clock. The rate of

the clock will be dependent upon the data rate that is programmed in the signalling field of the header.

TX_RDY

59

O

TX_RDY is an output to the external network processor indicating that Preamble and Header

information has been generated and that the HFA3861B is ready to receive the data packet from the

network processor over the TXD serial bus.

CCA

60

O

Clear Channel Assessment (CCA) is an output used to signal that the channel is clear to transmit. The

CCA may be configured to one of four possible algorithms. The CCA algorithm and its features are

described elsewhere in the data sheet.

Logic 0 = Channel is clear to transmit.

Logic 1 = Channel is NOT clear to transmit (busy).

This polarity is programmable and can be inverted.

RXD

53

O

RXD is an output to the external network processor transferring demodulated Header information and

data in a serial format. The data is sent serially with the LSB first. The data is frame aligned with

MD_RDY.

RXCLK

52

O

RXCLK is the bit clock output. This clock is used to transfer Header information and payload data

through the RXD serial bus to the network processor. This clock reflects the bit rate in use. RXCLK is

held to a logic “0” state during the CRC16 reception. RXCLK becomes active after the SFD has been

detected. Data should be sampled on the rising edge. This polarity is programmable and can be

inverted.

HFA3861B