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General Description
The MAX2440/MAX2441/MAX2442 highly integrated
front-end receiver ICs provide the lowest cost solution for
cordless phones and ISM-band radios operating in the
900MHz band. All devices incorporate receive image-
reject mixers to reduce filter cost. They operate with a
+2.7V to +4.8V power supply, allowing direct connection
to a 3-cell battery stack.
The signal path incorporates an adjustable-gain LNA
and an image-reject downconverter with 35dB image
suppression. These features yield excellent combined
downconverter noise figure (4dB) and high linearity with
an input third-order intercept point (IP3) of up to +2dBm.
All devices include an on-chip local oscillator (LO),
requiring only an external varactor-tuned LC tank for
operation. The integrated divide-by-64/65 dual-modulus
prescaler can also be set to a direct mode, in which it
acts as an LO buffer amplifier. Three separate power-
down inputs can be used for system power manage-
ment, including a 0.5µA shutdown mode. These parts
are compatible with commonly used modulation
schemes such as FSK, BPSK, and QPSK, as well as fre-
quency hopping and direct sequence spread-spectrum
systems. All devices come in a 28-pin SSOP package.
Evaluation kits are available for the MAX2420/
MAX2421/MAX2422. The MAX2420/MAX2421/MAX2422
are transceivers whose receive sections and pinout are
identical to the MAX2440/MAX2441/MAX2442.
For complete transceiver devices, refer to the MAX2420/
MAX2421/MAX2422/MAX2460/MAX2463 and MAX2424/
MAX2426 data sheets.
________________________Applications
Cordless Phones
Spread-Spectrum Communications
Wireless Telemetry
Two-Way Paging
Wireless Networks
Features
o
Receive Mixer with 35dB Image Rejection
o
Adjustable-Gain LNA
o
Up to +2dBm Combined Receiver Input IP3
o
4dB Combined Receiver Noise Figure
o
Low Current Consumption: 23mA Receive
9.5mA Oscillator
o
0.5µA Shutdown Mode
o
Operates from Single +2.7V to +4.8V Supply
MAX2440/MAX2441/MAX2442
900MHz Image-Reject Receivers
________________________________________________________________
Maxim Integrated Products
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
GND
GND
GND
TANK
GND
PREOUT
PREGND
MOD
DIV1
VCOON
RXON
GND
GND
GND
LNAGAIN
GND
GND
GND
RXIN
GND
RXOUT
CAP1
SSOP
TOP VIEW
MAX2440
MAX2441
MAX2442
TANK
V
CC
V
CC
V
CC
V
CC
V
CC
___________________Pin Configuration
19-1352; Rev 0; 4/98
PART
MAX2440
EAI
MAX2441
EAI
MAX2442
EAI
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
TEMP. RANGE
PIN-PACKAGE
28 SSOP
28 SSOP
28 SSOP
_______________Ordering Information
Functional Diagram appears at end of data sheet.
High side
INJECTION
TYPE
f
RF
+ 10.7
LO FREQ
(MHz)
High side
High side
f
RF
+ 70
f
RF
+ 46
MAX2442
MAX2441
70
46
MAX2440
PART
10.7
IF FREQ
(MHz)
______________________Selector Guide
EVALUATION KIT
AVAILABLE
MAX2440/MAX2441/MAX2442
900MHz Image-Reject Receivers
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +2.7V to +4.8V, no RF signals applied, LNAGAIN = unconnected, V
VCOON
= 2.4V, V
RXON
= V
MOD
= V
DIV1
= 0.45V, PREGND
= GND, T
A
= T
MIN
to T
MAX
. Typical values are at T
A
= +25°C, V
CC
= +3.3V, unless otherwise noted.)
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.
Note 1:
Calculated by measuring the combined oscillator and prescaler supply current and subtracting the oscillator supply current.
Note 2:
Calculated by measuring the combined oscillator and LO buffer supply current and subtracting the oscillator supply current.
Note 3:
Calculated by measuring the combined receive and oscillator supply current and subtracting the oscillator supply current.
With LNAGAIN = GND, the supply current drops by 4.5mA.
V
CC
to GND ...........................................................-0.3V to +5.5V
Voltage on LNAGAIN, RXON, VCOON,
DIV1, MOD ...............................................-0.3V to (V
CC
+ 0.3V)
RXIN Input Power..............................................................10dBm
TANK, TANK Input Power ...................................................2dBm
Continuous Power Dissipation (T
A
= +70°C)
SSOP (derate 9.50mW/°C above +70°C) ......................762mW
Operating Temperature Range
MAX244_EAI .....................................................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +165°C
Lead Temperature (soldering, 10sec) .............................+300°C
PARAMETER
MIN
TYP
MAX
UNITS
Receive Supply Current
23
36
mA
Prescaler Supply Current
(buffer mode)
5.4
8.5
mA
Oscillator Supply Current
Supply-Voltage Range
2.7
4.8
V
9.5
14
mA
Prescaler Supply Current
(divide-by-64/65 mode)
4.2
6
mA
CONDITIONS
V
RXON
= 2.4V, PREGND = unconnected (Note 3)
V
DIV1
= 2.4V (Note 2)
PREGND = unconnected
(Note 1)
Digital Input Voltage Low
0.45
V
0.5
RXON, DIV1, VCOON, MOD
VCOON = RXON = MOD =
DIV1 = GND
Digital Input Current
±1
±10
µA
Voltage on any one digital input = V
CC
or GND
Digital Input Voltage High
V
2.4
RXON, DIV1, VCOON, MOD
Shutdown Supply Current
10
µA
T
A
= +25°C
T
A
= T
MIN
to T
MAX
MAX2442
AC ELECTRICAL CHARACTERISTICS
(MAX242X/MAX246X EV kit, V
CC
= +3.3V; f
LO
= 925.7MHz (MAX2440), f
LO
= 961MHz (MAX2441), f
LO
= 985MHz (MAX2442),
f
RXIN
= 915MHz; P
RXIN
= -35dBm; V
LNAGAIN
= 2V; V
VCOON
= V
RXON
= 2.4V; RXON = MOD = DIV1 = PREGND = GND; T
A
= +25°C;
unless otherwise noted.)
MAX2440/MAX2441/MAX2442
900MHz Image-Reject Receivers
_______________________________________________________________________________________
3
CONDITIONS
UNITS
MIN
TYP
MAX
PARAMETER
MHz
800
1000
36
46
55
8.5
10.7
12.5
MHz
20
22
24.5
dB
26
35
Image Frequency Rejection
55
70
85
19.5
25
12
19
21
23.5
(Note 6)
-16
(Notes 4, 7)
dBm
-8
Input Third-Order Intercept
-19
-17
(Note 8)
ns
500
Receiver Turn-On Time
Receiver on or off
dBm
-60
LO to RXIN Leakage
V
LNAGAIN
= 1V
dBm
-18
Input 1dB Compression
LNAGAIN = V
CC
-26
18
24
LNAGAIN = V
CC
,
T
A
= T
MIN
to T
MAX
(Note 4)
4
5
dB
12
Noise Figure
RECEIVER
dB
IF Frequency Range
(Notes 4, 5)
(Notes 4, 5)
Input Frequency Range
Conversion Power Gain
DIV1 = V
CC
(Notes 4, 6)
MAX2441
MAX2442
LNAGAIN = V
CC
V
LNAGAIN
= 1V
V
LNAGAIN
= 1V
LNAGAIN = V
CC
MAX2442
V
LNAGAIN
= 1V
LNAGAIN = GND
MAX2440
LNAGAIN = V
CC
,
T
A
= +25°C
MAX2440/MAX2441
MAX2440/MAX2441
MAX2442
MAX2440/MAX2441/MAX2442
900MHz Image-Reject Receivers
4
_______________________________________________________________________________________
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX242X/MAX246X EV kit, V
CC
= +3.3V; f
LO
= 925.7MHz (MAX2440), f
LO
= 961MHz (MAX2441), f
LO
= 985MHz (MAX2442),
f
RXIN
= 915MHz; P
RXIN
= -35dBm; V
LNAGAIN
= 2V; V
VCOON
= V
RXON
= 2.4V; RXON = MOD = DIV1 = PREGND = GND; T
A
= +25°C;
unless otherwise noted.)
Oscillator Phase Noise
Oscillator Frequency Range
690
1100
MHz
82
dBc/Hz
8
(Notes 4, 9)
10kHz offset (Note 10)
Standby to RX
Note 4:
Guaranteed by design and characterization.
Note 5:
Image rejection typically falls to 30dBc at the frequency extremes.
Note 6:
Refer to the
Typical Operating Characteristics for plots showing receiver gain versus LNAGAIN voltage, input IP3 versus
LNAGAIN voltage, and noise figure versus LNAGAIN voltage.
Note 7:
Two tones at P
RXIN
= -45dBm each, f1 = 915.0MHz and f2 = 915.2MHz.
Note 8:
Time delay from RXON = 0.45V to RXON = 2.4V transition to the time the output envelope reaches 90% of its final value.
Note 9:
Refers to useable operating range. Tuning range of any given tank circuit design is typically much narrower (refer to Figure 1).
Note 10:
Using tank components shown in Figure 1.
Note 11:
This approximates a typical application in which a transmitter is followed by an external PA and a T/R switch with finite
isolation.
Note 12:
Relative to the rising edge of PREOUT.
Prescaler Output Level
500
mVp-p
-11
-8
Required Modulus Setup Time
10
ns
Z
L
= 100k
| |
10pF
Divide-by-64/65 mode (Notes 4, 12)
Required Modulus Hold Time
0
ns
Divide-by-64/65 mode (Notes 4, 12)
Standby mode with P
RXIN
= -45dBm to
P
RXIN
= 0dBm (Note 11)
70
Oscillator Buffer Output Level
-12
dBm
Oscillator Pulling
kHz
PARAMETER
MIN
TYP
MAX
UNITS
CONDITIONS
T
A
= T
MIN
to T
MAX
T
A
= +25°C
OSCILLATOR AND PRESCALER
DIV1 = 2.4V, Z
L
= 50
(Note 4)
MAX2440/MAX2441/MAX2442
900MHz Image-Reject Receivers
_______________________________________________________________________________________
5
24
28
26
34
32
30
40
38
36
42
-40
0
20
-20
40
60
80
100
RECEIVER SUPPLY CURRENT
vs. TEMPERATURE
MAX2440/1/2-01
TEMPERATURE (°C)
I
CC
(mA)
V
CC
= 2.7V
PREGND = UNCONNECTED
INCLUDES OSCILLATOR
CURRENT
V
CC
= 3.3V
V
CC
= 4.8V
0
1.0
0.5
2.5
2.0
1.5
4.0
3.5
3.0
4.5
-40
0
20
-20
40
60
80
100
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX2440/1/2-02
TEMPERATURE (°C)
I
CC
(
µ
A)
V
CC
= 2.7V
V
CC
= 3.3V
V
CC
= 4.8V
VCOON = GND
RXON = GND
25
20
15
10
5
0
-5
-10
-15
-20
0
0.5
1.0
1.5
2.0
RECEIVER GAIN vs. LNAGAIN
MAX2440/1/2-03
LNAGAIN VOLTAGE (V)
RECEIVER GAIN (dB)
ADJUSTABLE
GAIN
MAX
GAIN
LNA
PARTIALLY
BIASED
LNA
OFF
AVOID
THIS
REGION
18
22
20
26
24
-40
0
20
-20
40
60
80
100
MAX2440
RECEIVER GAIN vs. TEMPERATURE
MAX2440/1/2-06
TEMPERATURE (°C)
RECEIVER GAIN (dB)
V
CC
= 2.7V
V
CC
= 3.3V
V
CC
= 4.8V
LNAGAIN = V
CC
-20
-15
-10
-5
0
5
0
0.5
1.0
1.5
2.0
RECEIVER INPUT IP3 vs. V
LNAGAIN
MAX2440/1/2-04
LNAGAIN VOLTAGE (V)
IIP3 (dBm)
ADJUSTABLE
GAIN
AVOID
THIS
REGION
MAX
GAIN
LNA
PARTIALLY
BIASED
LNA
OFF
0
5
15
10
25
20
30
40
35
0
0.5
1.0
1.5
2.0
RECEIVER NOISE FIGURE
vs. LNAGAIN
MAX2440/1/2-05
LNAGAIN VOLTAGE (V)
NOISE FIGURE (dB)
ADJUSTABLE
GAIN
AVOID
THIS
REGION
MAX
GAIN
LNA
PARTIALLY
BIASED
LNA
OFF
DIV1 = V
CC
3.0
4.0
3.5
5.0
5.5
4.5
-40
0
20
-20
40
60
80
100
RECEIVER NOISE FIGURE vs.
TEMPERATURE AND SUPPLY VOLTAGE
MAX2440/1/2-07
TEMPERATURE (°C)
NOISE FIGURE (dB)
V
CC
= 2.7V
V
CC
= 3.3V
V
CC
= 4.8V
LNAGAIN = V
CC
DIV1 = V
CC
-20
-16
-18
-8
-10
-6
-12
-14
-40
0
20
-20
40
60
80
100
RECEIVER INPUT IP3
vs. TEMPERATURE
MAX2440/1/2-08
TEMPERATURE (°C)
IIP3 (dBm)
V
LNAGAIN
= 1V
V
LNAGAIN
= 2V
Typical Operating Characteristics
(MAX242X/MAX246X EV kit, V
CC
= +3.3V; f
LO
= 925.7MHz (MAX2440), f
LO
= 961MHz (MAX2441), f
LO
= 985MHz (MAX2442),
f
RXIN
= 915MHz; P
RXIN
= -35dBm; V
LNAGAIN
= 2V; V
VCOON
= 2.4V; RXON = V
CC
; MOD = DIV1 = PREGND = GND; T
A
= +25°C;
unless otherwise noted.)
-9
-8
-4
-5
-3
-6
-7
-40
0
20
-20
40
60
80
MAX2440
RXOUT 1dB COMPRESSION POINT
vs. TEMPERATURE
MAX2440/1/2-9
TEMPERATURE (°C)
1dB COMPRESSION POINT (dBm)
V
CC
= 2.7V
V
CC
= 4.8V
V
CC
= 3.3V
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