General Description
The MAX2820/MAX2821 single-chip zero-IF transceivers
are designed for the 802.11b (11Mbps) applications
operating in the 2.4GHz to 2.5GHz ISM band. The trans-
ceivers are nearly identical, except the MAX2821 pro-
vides a low-power shutdown mode and an analog
voltage reference output feature and the MAX2820 does
not. The transceivers include all the circuitry required to
implement an 802.11b RF-to-baseband transceiver solu-
tion, providing a fully integrated receive path, transmit
path, VCO, frequency synthesis, and baseband/control
interface. Only a PA, RF switch, RF BPF, and a small
number of passive components are needed to form the
complete radio front-end solution.
The ICs eliminate the need for external IF and base-
band filters by utilizing a direct-conversion radio archi-
tecture and monolithic baseband filters for both
receiver and transmitter. They are specifically opti-
mized for 802.11b (11Mbps CCK) applications. The
baseband filtering and RX and TX signal paths support
the CCK modulation scheme for BER = 10
-5
at the
required sensitivity levels.
The devices are suitable for the full range of 802.11b
data rates (1Mbps, 2Mbps, 5.5Mbps, and 11Mbps) and
also the higher-rate 22Mbps PBCC
TM
standard. The
MAX2820/MAX2821 are available in the very small 7mm
7mm 48-lead QFN package.
Applications
802.11b 11Mbps WLAN
802.11b
+
22Mbps PBCC High-Data-Rate WLAN
802.11a + b Dual-Band WLAN
2.4GHz ISM Band Radios
Features
o 2.4GHz to 2.5GHz ISM Band Operation
o 802.11b (11Mbps CCK and 22Mbps PBCC) PHY
Compatible
o Complete RF-to-Baseband Transceiver
Direct-Conversion Upconverters and
Downconverters
Monolithic Low-Phase-Noise VCO
Integrated Baseband Lowpass Filters
Integrated PLL with 3-Wire Serial Interface
Digital Bias Control for External PA
Transmit Power Control (Range > 25dB)
Receive Baseband AGC (Range > 65dB)
Complete Baseband Interface
Digital TX/RX Mode Control
Analog Receive Level Detection
o -97dBm RX Sensitivity at 1Mbps
o -87dBm RX Sensitivity at 11Mbps
o +2dBm Transmit Power (11Mbps CCK)
o Single +2.7V to +3.6V Supply
o Low-Current Shutdown Mode (MAX2821 only)
o Very Small 48-Pin QFN Package (s)
MAX2820/MAX2821
2.4GHz 802.11b Zero-IF Transceivers
________________________________________________________________ Maxim Integrated Products
1
Ordering Information
19-2493; Rev 2; 11/03
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
PART
TEMP RANGE
PIN-PACKAGE
MAX2820EGM-TD
-40
C to +85C
48 QFN
MAX2820ETM+TD
-40
C to +85C
48 QFN Lead Free
MAX2821EGM-TD
-40
C to +85C
48 QFN
MAX2821ETM+TD
-40
C to +85C
48 QFN Lead Free
Pin Configuration/Functional Diagram and Typical
Application Circuit appear at end of data sheet.
PBCC is a trademark of Texas Instruments, Inc.
MAX2820/MAX2821
2.4GHz 802.11b Zero-IF Transceivers
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(MAX2820/MAX2821 EV kit: V
CC
= +2.7V to +3.6V, RF_GAIN = V
IH
, 0V
V
TX_GC
+2.0V, 0V V
RX_AGC
+2.0V, RBIAS = 12k, no
input signals at RF and baseband inputs, all RF inputs and outputs terminated into 50
, receiver baseband outputs are open, trans-
mitter baseband inputs biased at +1.2V, registers set to default power-up settings, T
A
= -40
C to +85C, unless otherwise noted.
Typical values are at V
CC
= +2.7V, T
A
= +25
C, unless otherwise noted.) (Note 1)
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
V
CC
Pins to GND ...................................................-0.3V to +4.2V
RF Inputs: RX_RFP, RX_RFN to GND.........-0.3V to (V
CC
+ 0.3V)
RF Outputs: TX_RFP, TX_RFN to GND..................-0.3V to +4.2V
Baseband Inputs: TX_BBIP, TX_BBIN, TX_BBQP,
TX_BBQN to GND ...................................-0.3V to (V
CC
+ 0.3V)
Baseband Outputs: RX_BBIP, RX_BBIN, RX_BBQP,
RX_BBQN to GND ...................................-0.3V to (V
CC
+ 0.3V)
Analog Inputs: RX_AGC, TX_GC, TUNE, ROSCN,
ROSCP to GND .......................................-0.3V to (V
CC
+ 0.3V)
Analog Outputs: PA_BIAS, CP_OUT, VREF
to GND....................................................-0.3V to (V
CC
+ 0.3V)
Digital Inputs: RX_ON, TX_ON, SHDNB, CSB, SCLK,
DIN, RF_GAIN, RX_1K to GND...............-0.3V to (V
CC
+ 0.3V)
Bias Voltages: RBIAS, BYP ..................................+0.9V to +1.5V
Short-Circuit Duration Digital Outputs: DOUT, RX_DET .........10s
RF Input Power: RX_RFN, RX_RFP.................................+10dBm
Continuous Power Dissipation (T
A
= +70
C)
48-Lead QFN (derate 27.0mW/
C above +70C) .....2162mW
Operating Temperature Range ...........................-40
C to +85C
Junction Temperature ......................................................+150
C
Storage Temperature Range .............................-65
C to +160C
Lead Temperature (soldering, 10s) .................................+300
C
PARAMETERS
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage
2.7
3.6
V
Shutdown-Mode Supply Current
(MAX2821 Only)
SHDNB = V
IL
, RX_ON = V
IL
,
TX_ON = V
IL
T
A
= -40C to +85C
2
50
A
T
A
= +25C
25
35
Standby-Mode Supply Current
SHDNB = V
IH
, RX_ON = V
IL
,
TX_ON = V
IL
T
A
= -40C to +85C
40
mA
T
A
= +25C
80
100
Receive-Mode Supply Current
SHDNB = V
IH
, RX_ON = V
IH
,
TX_ON = V
IL
T
A
= -40C to +85C
110
mA
T
A
= +25C
70
85
Transmit-Mode Supply Current
SHDNB = V
IH
, RX_ON = V
IL
,
TX_ON = V
IH
T
A
= -40C to +85C
90
mA
LOGIC INPUTS: SHDNB, RX_ON, TX_ON, SCLK, DIN, CSB, RF_GAIN
Digital Input Voltage High (V
IH
)
V
CC
- 0.5
V
Digital Input Voltage Low (V
IL
)
0.5
V
Digital Input Current High (I
IH
)
-5
+5
A
Digital Input Current Low (I
IL
)
-5
+5
A
LOGIC OUTPUTS: DOUT, RX_DET
Digital Output Voltage High (V
OH
)
Sourcing 100A
V
CC
- 0.5
V
Digital Output Voltage Low (V
OL
)
Sinking 100A
0.5
V
RX BASEBAND I/O
RX_AGC Input Resistance
0V
V
RX_AGC
+2.0V
50
k
RX I/Q Common-Mode Voltage
1.25
V
RX I/Q Output DC Offsets
15
mV
VOLTAGE REFERENCE
Reference Voltage Output
T
A
= -40C to +85C, I
LOAD
= 2mA
1.1
1.2
1.3
V
Output Impedance
25
CAUTION! ESD SENSITIVE DEVICE
MAX2820/MAX2821
2.4GHz 802.11b Zero-IF Transceivers
_______________________________________________________________________________________
3
DC ELECTRICAL CHARACTERISTICS (continued)
(MAX2820/MAX2821 EV kit: V
CC
= +2.7V to +3.6V, RF_GAIN = V
IH
, 0V
V
TX_GC
+2.0V, 0V V
RX_AGC
+2.0V, RBIAS = 12k, no
input signals at RF and baseband inputs, all RF inputs and outputs terminated into 50
, receiver baseband outputs are open, trans-
mitter baseband inputs biased at +1.2V, registers set to default power-up settings, T
A
= -40
C to +85C, unless otherwise noted.
Typical values are at V
CC
= +2.7V, T
A
= +25
C, unless otherwise noted.) (Note 1)
AC ELECTRICAL CHARACTERISTICS--RECEIVE MODE
(MAX2820/MAX2821 EV kit: V
CC
= +2.7V to +3.6V, f
RF
and f
LO
= 2400MHz to 2499MHz, f
OSC
= 22MHz or 44MHz, receive baseband
outputs = 500mV
P-P
, SHDNB = RX_ON = V
IH
, TX_ON = V
IL
, CSB = V
IH
, SCLK = DIN = V
IL
, RF_GAIN = V
IH
, 0V
V
RX_AGC
+2.0V,
RBIAS = 12k
, I
CP
= +2mA, BW
PLL
= 45kHz, differential RF input matched to 50
, registers set to default power-up settings, T
A
=
+25
C, unless otherwise noted. Typical values are at V
CC
= +2.7V, f
LO
= 2437MHz, f
OSC
= 22MHz, unless otherwise noted.) (Note 1)
PARAMETERS
CONDITIONS
MIN
TYP
MAX
UNITS
TX BASEBAND I/O
TX BB Input Common-Mode
Range
1.0
1.2
1.4
V
TX BBI and BBQ Input Bias
Current
-10
A
TX BB Input Impedance
Differential resistance
100
k
TX_GC Input Bias Current
0V
V
TX_GC
+2.0V
10
A
TX_GC Input Impedance
Resistance
250
k
REFERENCE OSCILLATOR INPUT
Reference Oscillator Input
Impedance
20
k
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
RECEIVER CASCADE PERFORMANCE (RF INPUT TO BASEBAND OUTPUT)
RF Frequency Range
2400
2499
MHz
LO Frequency Range
2400
2499
MHz
T
A
= +25C
97
105
RF_GAIN = V
IH
,
V
RX_AGC
= 0V
T
A
= -40
C to +85C
95
RF_GAIN = V
IH
,
V
RX_AGC
= +2.0V
T
A
= +25
C
33
RF_GAIN = V
IL
,
V
RX_AGC
= 0V
T
A
= +25
C
75
Voltage Gain (Note 2)
RF_GAIN = V
IL
,
V
RX_AGC
= +2.0V
T
A
= +25
C
2
dB
RF Gain Step
From RF_GAIN = V
IH
to RF_GAIN =V
IL
30
dB
RF_GAIN = V
IH
, RX gain
80dB
3.5
4.5
RF_GAIN = V
IH
, RX gain = 50dB
4.5
DSB Noise Figure (Notes 3, 11)
RF_GAIN = V
IL
, RX gain = 50dB
34
dB
Adjacent Channel Rejection
RX gain = 70dB (Note 4)
49
dB
RF_GAIN = V
IH
, RX gain = 80dB
-14
Input Third-Order Intercept Point (Note 5)
RF_GAIN = V
IL
, RX gain = 50dB
18
dBm
RF_GAIN = V
IH
, RX gain = 80dB
22
Input Second-Order Intercept Point (Note 6)
RF_GAIN = V
IL
, RX gain = 50dB
60
dBm
MAX2820/MAX2821
2.4GHz 802.11b Zero-IF Transceivers
4
_______________________________________________________________________________________
AC ELECTRICAL CHARACTERISTICS--RECEIVE MODE (continued)
(MAX2820/MAX2821 EV kit: V
CC
= +2.7V to +3.6V, f
RF
and f
LO
= 2400MHz to 2499MHz, f
OSC
= 22MHz or 44MHz, receive baseband
outputs = 500mV
P-P
, SHDNB = RX_ON = V
IH
, TX_ON = V
IL
, CSB = V
IH
, SCLK = DIN = V
IL
, RF_GAIN = V
IH
, 0V
V
RX_AGC
+2.0V,
RBIAS = 12k
, I
CP
= +2mA, BW
PLL
= 45kHz, differential RF input matched to 50
, registers set to default power-up settings, T
A
=
+25
C, unless otherwise noted. Typical values are at V
CC
= +2.7V, f
LO
= 2437MHz, f
OSC
= 22MHz, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
LO Leakage
-65
dBm
Input Return Loss
With external match
15
dB
RECEIVER BASEBAND
BASEBAND FILTER RESPONSE
-3dB Frequency
Default bandwidth setting BW (2:0) = (010)
7
MHz
At 12.5MHz
40
At 16MHz
65
At 20MHz
70
Attenuation Relative to Passband
At 25MHz
85
dB
BASEBAND OUTPUT CHARACTERISTICS
RX I/Q Gain Imbalance
-1
+1
dB
RX I/Q Phase Quadrature Imbalance
-5
+5
Degrees
RX I/Q Output 1dB Compression
Differential voltage into 5k
1
V
P-P
RX I/Q Output THD
V
OUT
= 500mV
P-P
at 5.5MHz, Z
L
= 5k
||5pF
-35
dBc
BASEBAND AGC AMPLIFIER
AGC Range
V
RX_AGC
= 0 to +2.0V
70
dB
AGC Slope
Peak gain slope
60
dB/V
AGC Response Time
20dB gain step, 80dB to 60dB,
settling to
1dB
2
s
BASEBAND RX PEAK LEVEL DETECTION
RF_GAIN = V
IH
,
RX_DET = V
OL
to V
OH
-49
RX Detector Trip Point (at RX_RF)
CW signal
RF_GAIN = V
IL
,
RX_DET = V
OH
to V
OL
-54
dBm
RX Detector Hysteresis
5
dB
RX Detector Rise Time
With 3dB overdrive
1
s
AC ELECTRICAL CHARACTERISTICS--TRANSMIT MODE
(MAX2820/MAX2821 EV kit: V
CC
= +2.7V to +3.6V, f
RF
and f
LO
= 2400MHz to 2499MHz, f
OSC
= 22MHz or 44MHz, transmit baseband
inputs = 400mV
P-P
, SHDNB = TX_ON = V
IH
, RX_ON = V
IL
, CSB = V
IH
, 0V
V
TX_GC
+2.0V, RBIAS = 12k, I
CP
= +2mA, BW
PLL
=
45kHz, differential RF output matched to 50
through a balun, baseband input biased at +1.2V, registers set to default power-up set-
tings, T
A
= +25
C, unless otherwise noted. Typical values are at V
CC
= +2.7V, f
LO
= 2437MHz, f
OSC
= 22MHz, unless otherwise noted.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
TRANSMIT SIGNAL PATH: BASEBAND INPUT TO RF OUTPUT
RF Output Frequency Range
2400
2499
MHz
LO Output Frequency Range
2400
2499
MHz
MAX2820/MAX2821
2.4GHz 802.11b Zero-IF Transceivers
_______________________________________________________________________________________
5
AC ELECTRICAL CHARACTERISTICS--TRANSMIT MODE (continued)
(MAX2820/MAX2821 EV kit: V
CC
= +2.7V to +3.6V, f
RF
and f
LO
= 2400MHz to 2499MHz, f
OSC
= 22MHz or 44MHz, transmit baseband
inputs = 400mV
P-P
, SHDNB = TX_ON = V
IH
, RX_ON = V
IL
, CSB = V
IH
, 0V
V
TX_GC
+2.0V, RBIAS = 12k, I
CP
= +2mA, BW
PLL
=
45kHz, differential RF output matched to 50
through a balun, baseband input biased at +1.2V, registers set to default power-up set-
tings, T
A
= +25
C, unless otherwise noted. Typical values are at V
CC
= +2.7V, f
LO
= 2437MHz, f
OSC
= 22MHz, unless otherwise noted.)
AC ELECTRICAL CHARACTERISTICS--PA BIAS
(MAX2820/MAX2821 EV kit: V
CC
= +2.7V to +3.6V, SHDNB = V
IH
, TX_ON = V
IH
, CSB = V
IH
, PA_BIAS enabled, RBIAS = 12k
, regis-
ters set to default power-up settings, T
A
= +25
C, unless otherwise noted. Typical values are at V
CC
= +2.7V, unless otherwise noted.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
T
A
= +25
C
-1
+3
TX RF Output Power
V
IN
= 400mV
P - P
at
5.5M H z,
V
TX _GC
= 0V ,
I/Q C W si g nal (N ote 7)
T
A
= -40C to
+85C
-2
dBm
-22MHz
f
OFFSET
-11MHz,
11MHz
f
OFFSET
22MHz
-37
TX RF ACPR (Note 8)
-33MHz
f
OFFSET
< -22MHz,
22MHz < f
OFFSET
33MHz
-59
dBc
Unwanted sideband
-40
LO signal
-30
In-Band Spurious Signals Relative to
Modulated Carrier
f
RF
= 2400MHz to
2483MHz
Spurs >
22MHz
-80
dBc
2
f
LO
-40
TX RF Harmonics
3
f
LO
-55
dBm
f
RF
< 2400MHz
-60
f
RF
= 2500MHz to 3350MHz
-43
TX RF Spurious Signal Emissions
(Outside 2400MHz to 2483.5MHz)
Nonharmonic Signals
f
RF
> 3350MHz
-45
dBm
TX RF Output Noise
f
OFFSET
22MHz, 0V V
TX_GC
+2.0V
-135
dBm/Hz
TX RF Output Return Loss
With external match
15
dB
TX BASEBAND FILTER RESPONSE
-3dB Frequency
10
MHz
At 22MHz
25
Attenuation Relative to Passband
At 44MHz
50
dB
TX GAIN-CONTROL CHARACTERISTICS
Gain-Control Range
0V
V
TX_GC
+2.0V
30
dB
Gain-Control Slope
Peak gain slope
40
dB/V
Gain-Control Response Time
V
TX_GC
= +2.0V to 0V step
0.3
s
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Resolution
4
Bits
Full-Scale Output Current
300
A
LSB Size
20
A
Output Voltage Compliance Range
(Note 11)
1.0
1.2
1.3
V
Settling Time
Relative to rising edge of CSB, zero to full-
scale step 0000
1111, settle to 1/2 LSB,
2pF load
1
s
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