19-1352; Rev 3; 8/03
IT
TION K
VALUA
E
BLE
AVAILA
900MHz Image-Reject Receivers
General Description
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
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.
_______________Ordering Information
PART
MAX2440EAI
MAX2441EAI
MAX2442EAI
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 SSOP
28 SSOP
28 SSOP
Functional Diagram appears at end of data sheet.
___________________Pin Configuration
TOP VIEW
V
CC
1
28 GND
27 GND
26 GND
25 TANK
CAP1 2
RXOUT 3
GND 4
RXIN 5
V
CC
6
GND 7
________________________Applications
Cordless Phones
Wireless Telemetry
Wireless Networks
Spread-Spectrum Communications
Two-Way Paging
MAX2440
MAX2441
MAX2442
24 TANK
23 V
CC
22 V
CC
21 PREOUT
20 PREGND
19 MOD
18 DIV1
17 VCOON
16 RXON
15 GND
______________________Selector Guide
PART
MAX2440
MAX2441
MAX2442
IF FREQ
(MHz)
10.7
46
70
INJECTION
TYPE
High side
High side
High side
LO FREQ
(MHz)
f
RF
+ 10.7
f
RF
+ 46
f
RF
+ 70
GND 8
GND 9
LNAGAIN 10
V
CC
11
GND 12
GND 13
GND 14
SSOP
________________________________________________________________
Maxim Integrated Products
1
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.
900MHz Image-Reject Receivers
MAX2440/MAX2441/MAX2442
ABSOLUTE MAXIMUM RATINGS
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, 10s) .................................+300°C
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.
CAUTION!
ESD SENSITIVE DEVICE
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.) (Note 1)
PARAMETER
Supply-Voltage Range
Oscillator Supply Current
Prescaler Supply Current
(divide-by-64/65 mode)
Prescaler Supply Current
(buffer mode)
Receive Supply Current
Shutdown Supply Current
Digital Input Voltage High
Digital Input Voltage Low
Digital Input Current
Note 1:
Note 2:
Note 3:
Note 4:
PREGND = unconnected
(Note 2)
V
DIV1
= 2.4V (Note 3)
V
RXON
= 2.4V, PREGND = unconnected (Note 4)
VCOON = RXON = MOD =
DIV1 = GND
RXON, DIV1, VCOON, MOD
RXON, DIV1, VCOON, MOD
Voltage on any one digital input = V
CC
or GND
±1
T
A
= +25°C
T
A
= T
MIN
to T
MAX
2.4
0.45
±10
CONDITIONS
MIN
2.7
9.5
4.2
5.4
23
0.5
10
TYP
MAX
4.8
14
6
8.5
36
UNITS
V
mA
mA
mA
mA
µA
V
V
µA
≥25°C
guaranteed by production test, <25°C guaranteed through correlation to worst-case temperature testing.
Calculated by measuring the combined oscillator and prescaler supply current and subtracting the oscillator supply current.
Calculated by measuring the combined oscillator and LO buffer supply current and subtracting the oscillator supply current.
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.
2
_______________________________________________________________________________________
900MHz Image-Reject Receivers
MAX2440/MAX2441/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.)
PARAMETER
RECEIVER
Input Frequency Range
(Notes 5, 6)
MAX2440
IF Frequency Range
Image Frequency Rejection
LNAGAIN = V
CC
,
T
A
= +25°C
Conversion Power Gain
(Note 7)
LNAGAIN = V
CC
,
T
A
= T
MIN
to T
MAX
(Note 5)
V
LNAGAIN
= 1V
LNAGAIN = GND
Noise Figure
Input Third-Order Intercept
Input 1dB Compression
LO to RXIN Leakage
Receiver Turn-On Time
DIV1 = V
CC
(Notes 5, 7)
(Notes 5, 8)
LNAGAIN = V
CC
V
LNAGAIN
= 1V
Receiver on or off
(Note 9)
LNAGAIN = V
CC
V
LNAGAIN
= 1V
LNAGAIN = V
CC
V
LNAGAIN
= 1V
-19
MAX2440/MAX2441
MAX2442
MAX2440/MAX2441
MAX2442
(Notes 5, 6)
MAX2441
MAX2442
800
8.5
36
55
26
20
19
19.5
18
12
-16
4
12
-17
-8
-26
-18
-60
500
5
dB
dBm
dBm
dBm
ns
10.7
46
70
35
22
21
24.5
23.5
25
dB
24
1000
12.5
55
85
dB
MHz
MHz
CONDITIONS
MIN
TYP
MAX
UNITS
_______________________________________________________________________________________
3
900MHz Image-Reject Receivers
AC ELECTRICAL CHARACTERISTICS (continued)
MAX2440/MAX2441/MAX2442
(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.)
PARAMETER
OSCILLATOR AND PRESCALER
Oscillator Frequency Range
Oscillator Phase Noise
Oscillator Pulling
Prescaler Output Level
Oscillator Buffer Output Level
Required Modulus Setup Time
(Notes 5, 10)
CONDITIONS
MIN
TYP
MAX
UNITS
690
82
8
70
500
T
A
= +25°C
T
A
= T
MIN
to T
MAX
-11
-12
10
-8
1100
MHz
dBc/Hz
kHz
mVp-p
dBm
ns
10kHz offset (Note 11)
Standby to RX
Standby mode with P
RXIN
= -45dBm to
P
RXIN
= 0dBm (Note 12)
Z
L
= 100kΩ
| |
10pF
DIV1 = 2.4V, Z
L
= 50Ω
(Note 5)
Divide-by-64/65 mode (Notes 5, 13)
Note 5:
Guaranteed by design and characterization.
Note 6:
Image rejection typically falls to 30dBc at the frequency extremes.
Note 7:
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 8:
Two tones at P
RXIN
= -45dBm each, f1 = 915.0MHz and f2 = 915.2MHz.
Note 9:
Time delay from RXON = 0.45V to RXON = 2.4V transition to the time the output envelope reaches 90% of its final value.
Note 10:
Refers to useable operating range. Tuning range of any given tank circuit design is typically much narrower (refer to Figure 1).
Note 11:
Using tank components L3 = 5.0nH (Coilcraft A02T), C2 = C3 = C26 = 3.3pF, R6 = R7 = 10Ω.
Note 12:
This approximates a typical application in which a transmitter is followed by an external PA and a T/R switch with finite
isolation.
Note 13:
Relative to the rising edge of PREOUT.
4
_______________________________________________________________________________________
900MHz Image-Reject Receivers
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.)
RECEIVER SUPPLY CURRENT
vs. TEMPERATURE
MAX2440/1/2-01
MAX2440/MAX2441/MAX2442
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX2440/1/2-02
RECEIVER GAIN vs. LNAGAIN
20
15
RECEIVER GAIN (dB)
10
5
0
-5
-10
AVOID
THIS
REGION
ADJUSTABLE
GAIN
MAX
GAIN
LNA
OFF
LNA
PARTIALLY
BIASED
MAX2440/1/2-03
42
40
38
36
I
CC
(mA)
34
32
30
28
26
24
-40
-20
0
20
40
60
80
PREGND = UNCONNECTED
INCLUDES OSCILLATOR
CURRENT
V
CC
= 4.8V
4.5
4.0
3.5
3.0
I
CC
(µA)
2.5
2.0
1.5
1.0
0.5
0
-40
-20
0
20
40
V
CC
= 2.7V
60
80
V
CC
= 4.8V
V
CC
= 3.3V
VCOON = GND
RXON = GND
25
V
CC
= 3.3V
V
CC
= 2.7V
-15
-20
100
0
0.5
100
1.0
1.5
2.0
TEMPERATURE (°C)
TEMPERATURE (°C)
LNAGAIN VOLTAGE (V)
RECEIVER INPUT IP3 vs. V
LNAGAIN
MAX2440/1/2-04
RECEIVER NOISE FIGURE
vs. LNAGAIN
MAX2440/1/2-05
MAX2440
RECEIVER GAIN vs. TEMPERATURE
LNAGAIN = V
CC
26
RECEIVER GAIN (dB)
V
CC
= 2.7V
V
CC
= 4.8V
MAX2440/1/2-06
5
LNA
OFF
LNA
ADJUSTABLE MAX
PARTIALLY
GAIN
GAIN
BIASED
AVOID
THIS
REGION
40
35
30
NOISE FIGURE (dB)
25
20
15
10
AVOID
THIS
REGION
0
0.5
1.0
LNA
OFF
LNA
ADJUSTABLE MAX
PARTIALLY
GAIN
GAIN
BIASED
0
24
22
IIP3 (dBm)
-5
-10
20
V
CC
= 3.3V
-15
5
-20
0
0.5
1.0
1.5
2.0
LNAGAIN VOLTAGE (V)
0
18
DIV1 = V
CC
1.5
2.0
-40
-20
0
20
40
60
80
100
LNAGAIN VOLTAGE (V)
TEMPERATURE (°C)
RECEIVER NOISE FIGURE vs.
TEMPERATURE AND SUPPLY VOLTAGE
MAX2440/1/2-07
RECEIVER INPUT IP3
vs. TEMPERATURE
MAX2440/1/2-08
MAX2440
RXOUT 1dB COMPRESSION POINT
vs. TEMPERATURE
MAX2440/1/2-9
5.5
LNAGAIN = V
CC
DIV1 = V
CC
5.0
NOISE FIGURE (dB)
V
CC
= 4.8V
-6
-8
-10
IIP3 (dBm)
-12
-14
-16
-18
V
LNAGAIN
= 1V
-3
1dB COMPRESSION POINT (dBm)
-4
V
CC
= 4.8V
-5
-6
-7
-8
-9
V
CC
= 2.7V
V
CC
= 3.3V
4.5
V
CC
= 3.3V
4.0
V
CC
= 2.7V
3.5
V
LNAGAIN
= 2V
3.0
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
-20
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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