MAX2820ETM-T Maxim Integrated Products, MAX2820ETM-T Datasheet - Page 15

• Manufacturer Part Number: MAX2820ETM-T
• Description: RF Transceiver 2.4GHz 802.11b Zero-If Transceiver
• Manufacturer: Maxim Integrated Products

Specifications of MAX2820ETM-T

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX2820/MAX2821 have four primary modes of
operation: shutdown, standby, receive active, and
transmit active. The modes are controlled by the digital
inputs SHDNB, TX_ON, and RX_ON. Table 1 shows the
operating mode vs. the digital mode control input.
Shutdown mode is achieved by driving SHDNB low. In
shutdown mode, all circuit blocks are powered down,
except for the serial interface circuitry. While the device
is in shutdown, the serial interface registers can still be
loaded by applying V
(VCC_DIG). All previously programmed register values
are preserved during the shutdown mode, as long as
VCC_DIG is applied.
Standby mode is achieved by driving SHDNB high and
RX_ON and TX_ON low. In standby mode, the PLL,
VCO, LO generator, LO buffer, LO quadrature, and fil-
ter autotuner are powered on by default. The standby
mode is intended to provide time for the slower-settling
circuitry (PLL and autotuner) to turn on and settle to the
correct frequency before making RX or TX active. The
3-wire serial interface is active and can load register
Figure 1. MAX2820/MAX2821 Serial-Interface Timing Diagram
Table 1. Operating-Mode Truth Table
OPERATING MODE
Shutdown
Transmit
Standby
Receive
DOUT
SCLK
______________________________________________________________________________________
CSB
DIN
CC
SHDNB
to the digital supply voltage
2.4GHz 802.11b Zero-IF Transceivers
t
CSO
Operating Modes
MODE CONTROL INPUTS
0
1
1
1
BIT 1
t
DV
Shutdown Mode
t
CSS
Standby Mode
t
TX_ON
DS
BIT 2
BIT 1
X
0
0
1
BIT 6
BIT 2
t
DO
RX_ON
X
0
1
0
BIT 7
BIT 6
t
DH
BIT 8
BIT 7
values at any time. Refer to the serial-interface specifi-
cation for details.
Receive mode is enabled by driving the digital inputs
SHDNB high, RX_ON high, and TX_ON low. In receive
mode, all receive circuit blocks are powered on and all
VCO, PLL, and autotuner circuits are powered on. None of
the transmit path blocks are active in this mode. Although
the receiver blocks turn on quickly, the DC offset nulling
requires ~10µs to settle. The receiver signal path is ready
~10µs after a low-to-high transition on RX_ON.
Transmit mode is achieved by driving the digital inputs
SHDNB high, RX_ON low, and TX_ON high. In transmit
mode, all transmit circuit blocks are powered on and all
VCO, PLL, and autotuner circuits are powered on.
None of the receive path blocks is active in this mode.
Although the transmitter blocks turn on quickly, the
baseband DC offset calibration requires ~2.2µs to
complete. In addition, the TX driver amplifier is ramped
from the low-gain state (minimum RF output) to high-
gain state (peak RF output) over the next 1µs to 2µs.
The transmit signal path is ready ~4µs after a low-to-
high transition on TX_ON.
RX_PATH
OFF
OFF
OFF
BIT 14
ON
BIT 8
t
CH
BIT 15
BIT 14
CIRCUIT BLOCK STATES
t
CL
BIT 15
BIT 16
TX_PATH
t
CSH
OFF
OFF
OFF
ON
BIT 16
t
CSW
t
TR
t
CS1
Transmit Mode
Receive Mode
PLL/VCO/LO GEN.
OFF
ON
ON
ON
15