19-1350 Rev 2; 2/99
900MHz Image-Reject Receivers
with Transmit Mixer
/MAX426
________________General Description
____________________________Features
♦ Receive Mixer with 35dB Image Rejection
♦ Adjustable-Gain LNA
The MAX2424/MAX2426 highly integrated front-end ICs
provide the lowest cost solution for cordless and ISM-
band radios operating in the 900MHz band. Both devices
incorporate a receive image-reject mixer (to reduce filter
cost) as well as a versatile transmit mixer. The devices
operate from a +2.7V to +4.8V single power supply,
allowing direct connection to a 3-cell battery stack.
♦ Up to +2dBm Combined Receiver Input IP3
♦ 4dB Combined Receiver Noise Figure
♦ Optimized for Common Receiver IF Frequencies:
10.7MHz (MAX2424)
The receive 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 (IIP3) of up to +2dBm.
70MHz (MAX2426)
♦ PA Predriver Provides up to 0dBm
♦ Low Current Consumption: 23mA Receive
20mA Transmit
The transmitter consists of a double-balanced mixer and
a power amplifier (PA) predriver that produces up to
0dBm (in some applications serving as the final power
stage). It can be used in a variety of configurations,
including BPSK modulation, direct VCO modulation, and
transmitter upconversion. For devices featuring trans-
mit as well as receive image rejection, refer to the
MAX2420/MAX2421/MAX2422/MAX2460/MAX2463
data sheet.
9.5mA Oscillator
♦ 0.5µA Shutdown Mode
♦ Operates from Single +2.7V to +4.8V Supply
_______________Ordering Information
PART
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
MAX2424EAI
MAX2426EAI
28 SSOP
The MAX2424/MAX2426 have an on-chip local oscillator
(LO), requiring only an external varactor-tuned LC tank
for operation. The integrated divide-by-64/65 dual-mod-
ulus prescaler can also be set to a direct mode, in which
it acts as an LO buffer amplifier. Four separate power-
down inputs can be used for system power manage-
ment, including a 0.5µA shutdown mode.
28 SSOP
___________________Pin Configuration
The MAX2424/MAX2426 come in a 28-pin SSOP pack-
age.
TOP VIEW
V
28
27
26
25
24
23
22
21
GND
GND
GND
CC
1
2
3
4
5
6
7
8
9
________________________Applications
Cordless Phones
CAP1
RXOUT
GND
TANK
TANK
Wireless Telemetry
RXIN
MAX2424
MAX2426
Wireless Networks
V
CC
V
CC
V
Spread-Spectrum Communications
Two-Way Paging
GND
GND
CC
PREOUT
20 PREGND
19
TXOUT
MOD
18 DIV1
LNAGAIN 10
V
CC
11
12
13
14
VCOON
17
16
15
TXIN
TXIN
RXON
TXON
Functional Diagram appears at end of data sheet.
CAP2
SSOP
________________________________________________________________ Maxim Integrated Products
1
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For small orders, phone 1-800-835-8769.