19-1093; Rev 2; 1/98
AL
ANU
T M EET
KI
SH
ION
UAT S DATA
AL
EV
LOW
FOL
Low-Voltage, Silicon RF Power
Amplifier/Predriver
____________________________Features
o
Operates Over the 800MHz to 1000MHz Frequency
Range
o
Delivers 125mW at 915MHz from +3.6V Supply
(100mW typical from +3.0V supply)
o
Operates Directly from 3-Cell NiCd or 1-Cell
Lithium-Ion Battery
o
Over 32dB Power Gain
o
RF Power Envelope Ramping is Programmable
with One External Capacitor
o
Input Matched to 50Ω (VSWR < 2:1)
o
15dB Output Power Control Range
o
1µA Typical Shutdown Current
________________General Description
The MAX2430 is a versatile, silicon RF power amplifier
that operates directly from a 3V to 5.5V supply, making
it suitable for 3-cell NiCd or 1-cell lithium-ion battery
applications. It is designed for use in the 800MHz to
1000MHz frequency range and, at 915MHz, can pro-
duce +21dBm (125mW) of output power with greater
than 32dB of gain at V
CC
= 3.6V.
A unique shutdown function provides an off supply cur-
rent of typically less than 1µA to save power during
“idle slots” in time-division multiple-access (TDMA)
transmissions. An external capacitor sets the RF output
power envelope ramp time. External power control is
also possible over a 15dB range. The amplifier’s input
is matched on-chip to 50Ω. The output is an open col-
lector that is easily matched to a 50Ω load with few
external components.
The MAX2430 is ideal as a driver amplifier for portable
and mobile telephone systems, or as a complete power
amplifier for other low-cost applications, such as those
in the 915MHz spread-spectrum ISM band. It is fabri-
cated with Maxim’s high-frequency bipolar transistor
process and is available in a thermally enhanced,
16-pin narrow SO and miniature 16-pin PwrQSOP pack-
ages with heat slug.
MAX2430
Ordering Information
PART
MAX2430IEE
MAX2430ISE
TEMP. RANGE
-20°C to +85°C
-20°C to +85°C
PIN-PACKAGE
16 PwrQSOP
16 Narrow SO
________________________Applications
Digital Cordless Phones
915MHz ISM-Band Applications
Two-Way Pagers
Wireless LANs
Cellular Phones
AM and FM Analog Transmitters
Pin Configuration
Functional Diagram
VCC1
7
SHDN
2
MASTER
BIAS
6
4
OUTPUT
BIAS
VCC2
8
BIAS
10
TOP VIEW
GND3 1
SHDN 2
GND2 3
9
RFOUT
RFIN 4
GND2 5
GND1 6
16 GND3
15 GND3
14 GND4
GND1
RFIN
MAX2430
DRIVER
GAIN
3, 5
GND2
1, 15, 16
GND3
MAX2430
13 GND4
12 GND4
11 GND4
10 BIAS
9
RFOUT
11, 12, 13, 14
GND4
VCC1 7
VCC2 8
NOTE: MAX2430IEE (PwrQSOP PACKAGE) UNDERSIDE METAL
SLUG MUST BE SOLDERED TO PCB GROUND PLANE.
Narrow SO/PwrQSOP
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Low-Voltage, Silicon RF Power
Amplifier/Predriver
MAX2430
ABSOLUTE MAXIMUM RATINGS
VCC1, VCC2 ..........................................................................+6V
SHDN,
BIAS...................................................-0.3V, (V
CC
+ 0.3V)
RFIN.............................................................................-0.3V, +2V
P
RFIN
..................................................................................-3dBm
Continuous Power Dissipation (T
A
= +70°C)
PwrQSOP (derate 20mW/°C above +70°C) ......................1.6W
Narrow SO (derate 20mW/°C above +70°C) ....................1.6W
Operating Temperature Range ...........................-20°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+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.
DC ELECTRICAL CHARACTERISTICS
(V
CC
= VCC1 = VCC2 = RFOUT = 3V to 5.5V, GND1 = GND2 = GND3 = GND4 = 0V,
SHDN
= 2.2V, BIAS = open, RFIN = open,
T
A
= -20°C to +85°C, unless otherwise noted.)
PARAMETER
Supply Voltage Range
Supply Current
Shutdown Supply Current
BIAS Pin Voltage
SHDN
High Input
SHDN
Low Input
SHDN
Bias Current
SYMBOL
V
CC
I
CC
I
CC(OFF
)
V
BIAS
V
SHDN(HI)
V
SHDN(LO)
I
SHDN
SHDN
= V
CC
No RF input applied, V
CC
= 5.5V
SHDN
= low
BIAS pin open
2.2
CONDITIONS
MIN
3
52
1
2.2
V
CC
0.4
18
TYP
MAX
5.5
70
10
UNITS
V
mA
µA
V
V
V
µA
AC ELECTRICAL CHARACTERISTICS
(MAX2430 EV kit, f = 915MHz, V
CC
= 3.6V,
SHDN
= V
CC
, RFOUT matched to 50Ω resistive load, output measurements taken after
matching network, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Frequency Range
P
OUT
at 1dB Compression
Power Gain
Output IM3
2nd Harmonic
3rd Harmonic
Efficiency
Supply Current
Maximum Input VSWR
Maximum Output Load
Mismatch
Maximum Output Load
Mismatch for Stability
Noise Figure
2
η
I
CCRF
VSWR
IN
VSWR
OUT
VSWR
OUT
NF
P
1dB
G
P
OIM3
SYMBOL
(Note 2)
V
CC
= 3.6V
V
CC
= 3.0V
P
RFIN
= -20dBm
MAX2430ISE
MAX2430IEE
CONDITIONS
MIN
800
20
19
32
31
21.4
20.4
34
33
-30
-26
-40
24
160
2:1
8:1
6:1
7
dB
TYP
MAX
1000
UNITS
MHz
dBm
dB
dBc
dBc
dBc
%
mA
f1 = 915MHz, f2 = 916MHz,
P
OUT
per tone = 14dBm
P
OUT
= P
1dB
P
OUT
= P
1dB
P
OUT
= P
1dB
P
OUT
= P
1dB
RFIN connected to 50Ω source
V
CC
= 3V to 5.5V, P
RFIN
≤
-10dBm (Note 3)
V
CC
= 3V to 5.5V, P
RFIN
≤
-12dBm (Note 4)
_______________________________________________________________________________________
Low-Voltage, Silicon RF Power
Amplifier/Predriver
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2430 EV kit, f = 915MHz, V
CC
= 3.6V,
SHDN
= V
CC
, output matched to 50Ω resistive load, output measurements taken after
matching network, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
RFIN to RFOUT Isolation
Turn-On/Off Times
SYMBOL
SHDN
= 0.4V,
P
IN
= -10dBm
CONDITIONS
MAX2430ISE
MAX2430IEE
MIN
TYP
50
47
1
10
MAX
UNITS
dB
dB
µs
MAX2430
BIAS pin capacitor C1 = 120pF
BIAS pin capacitor C1 = 2.2nF
Note 1:
Minimum and maximum parameters are guaranteed by design.
Note 2:
For optimum performance at a given frequency, output matching network must be designed for maximum output power.
See
Applications Information
section. Operation outside this frequency range is possible but has not been characterized.
Note 3:
No damage to the device.
Note 4:
All non-harmonically related outputs are more than 60dB below the desired signal for any electrical phase.
__________________________________________Typical Operating Characteristics
(MAX2430EVKIT-SO, f = 915MHz, V
CC
= 3.6V,
SHDN
= V
CC
, output matched to 50Ω resistive load, output measurements taken after
matching network, T
A
= +25°C, unless otherwise noted.)
OUTPUT POWER AND CURRENT
vs. INPUT POWER
25
5.5V
250
3.6V
3V
200
5.5V
P
OUT
(dBm)
15
P
OUT
3.6V
3V
P
OUT
(dBm)
I
CC
(mA)
150
20
P
OUT
@ P
IN
= -17dBm
I
CC
(mA)
15
I
CC
@ P
IN
= -12dBm
150
200
25
P
OUT
@ P
IN
= -12dBm
OUTPUT POWER AND CURRENT
vs. TEMPERATURE
GAIN (dB)
250
40
35
30
25
P
OUT
(dBm)
20
GAIN
OUTPUT POWER AND GAIN
vs. INPUT POWER
MAX2430-03
20
5.5V
3V
3.6V
5.5V
10
I
CC
100
3.6V
15
10
5
-25
-20
-15
P
IN
(dBm)
-10
-5
P
OUT
3V
5
50
10
-5.5V
3.6V
3V
0
I
CC
@ P
IN
= -17dBm
100
0
-25
-20
-15
P
IN
(dBm)
-10
-5
0
5
-20
20
40
60
TEMPERATURE (°C)
80
50
100
OUTPUT POWER AND GAIN
vs. TEMPERATURE
(NORMAL OPERATING MODE)
MAX1691-4a
INPUT VSWR
vs. FREQUENCY
MAX2430-05
RF INPUT IMPEDANCE
vs. FREQUENCY
MAX2430-06
35
GAIN (dB)
4.0
3.5
150
100
INPUT IMPEDANCE (Ω)
50
0
IMAG
-50
REAL
30
5.5V
3.6V
3.0V
GAIN
P
IN
= -12dBm
P
OUT
3.0
VSWR
3V
2.5
2.0
25
P
OUT
(dBm)
20
1.5
15
-20
0
20
40
60
80
100
TEMPERATURE (°C)
1.0
400
600
5V
-100
-150
800 1000 1200 1400
FREQUENCY (MHz)
1600
400
800
1200
1600
FREQUENCY (MHz)
2000
_______________________________________________________________________________________
3
Low-Voltage, Silicon RF Power
Amplifier/Predriver
MAX2430
_____________________________Typical Operating Characteristics (continued)
(MAX2430EVKIT-SO, f = 915MHz, V
CC
= 3.6V,
SHDN
= V
CC
, output matched to 50Ω resistive load, output measurements taken after
matching network, T
A
= +25°C, unless otherwise noted.)
INTERMODULATION DISTORTION vs.
OUTPUT POWER AND TEMPERATURE
MAX2430-07
MAX2430-08
OUTPUT POWER AND HARMONICS
INTERMODULATION DISTORTION (dBc)
V
CC
= 3.0V
+20.4dBm f1 = 915MHz
20
–
P
OUT
= +20.4dBm V
CC
= 3.6V
V
CC
= 4.5V
V
CC
= 5.5V
10
–
-4.93dBm
0
–
-16.7dBm
-47.6
-10
–
dBm
-20
–
-35.3dBm
-30
–
-40
–
-50
–
-60
1
2
3
4
5
6
HARMONIC NUMBER
-54.0
dBm
30
-20
-25
-30
-35
-40
-45
-50
-55
-60
INTERMODULATION DISTORTION
vs. OUTPUT POWER AND V
CC
INTERMODULATION DISTORTION (dBc)
-25
-30
-35
-40
-45
-50
-55
-60
-65
-70
-75
-10
IM5
-5
0
5
10
15
20
IM3
5.5V
3.0V
3.6V
5.5V
3.0V
3.6V
MAX2430-09
MAX2430-10
-20
OUTPUT SPECTRUM (dBm)
T
A
= -20°C
T
A
= +25°C
T
A
= +85°C
V
CC
= 3.6V
f1 = 915MHz
f2 = 916MHz
IM3
IM5
T
A
= -20°C
T
A
= +25°C
T
A
= +85°C
-10
-5
0
5
10
15
20
-65
-15
OUTPUT POWER PER TONE (dBm)
OUTPUT POWER PER TONE (dBm)
OUTPUT POWER AND SUPPLY CURRENT
vs. EXTERNAL CONTROL VOLTAGE
25
PIN = -12dBm
V
CC
= 3.6V
20
T
A
= +85°C
15
T
A
= -20°C
10
T
A
= +25°C
5
T
A
= -20°C
0
T
A
= +25°C
-5
-10
-15
0.4
0.8
1.2
1.6
2.0
BIAS PIN VOLTAGE (V)
T
A
= +85°C
P
OUT
200
I
CC
175
150
125
100
75
50
25
0
2.4
I
CC
(mA)
1V/div
RF OUTPUT ENVELOPE CHARACTERISTICS
vs. SHUTDOWN CONTROL
3V
0V
SHDN
0V
3V
OUTPUT POWER (dBm)
V
CC
= 3.0V
BIAS CAPACITOR = 1nF
P
OUT
= 20.4dBm (110mW)
t
ON
≈
t
OFF
= 5µs
5µs/div
4
_______________________________________________________________________________________
Low-Voltage, Silicon RF Power
Amplifier/Predriver
_____________________Pin Description
PIN
1, 15,
16
2
3, 5
NAME
GND3
SHDN
GND2
FUNCTION
Driver Stage Ground. Connect directly to
ground plane.
Shutdown Input (TTL/CMOS)
Input Stage Ground. Connect directly to
ground plane.
RF Input. Internally matched to 50Ω.
Requires series DC-blocking capacitor.
Bias Circuitry Ground. Connect directly to
ground plane.
Bias Circuitry Supply. Connect to supply.
Bypass with 1000pF capacitor.
Driver Stage Output. Connect to supply
through inductor (see
Applications
Information).
Output Transistor. Open Collector.
Output Stage Bias Pin. Connect capacitor
to GND to control start-up power enve-
lope. Drive directly for power control (see
Applications Information).
Output Stage Ground. Connect directly to
ground plane.
Detailed Description
The MAX2430 consists of a large power output transis-
tor driven by a capacitively coupled driver stage (see
Functional Diagram
). The driver and front-end gain
stages are DC-connected and biased on-chip from the
master bias cell. The master bias cell also controls the
output stage bias circuit. The input impedance at the
RFIN pin is internally matched to 50Ω, while the output
stage must be tuned and filtered externally for any nar-
row-band frequency range of interest between 800MHz
and 1000MHz.
The driver amplifier requires an external inductor at the
VCC2 pin to provide DC bias and proper matching to
the output stage. This inductor’s value depends on the
package type and frequency range of operation; typi-
cally it will vary between 5nH and 22nH.
The output transistor at the RFOUT pin requires an
external RF choke inductor connected to the supply for
DC bias, and a matching network to transform the
desired external load impedance to the optimal internal
load impedance of approximately 15Ω.
The MAX2430 includes a unique shutdown feature. The
TTL/CMOS-compatible
SHDN
input allows the device to
be shut down completely without the use of any exter-
nal components. Also, the RF output power envelope
ramp time can be programmed with a single external
capacitor connected between the BIAS pin and
ground. Pulling the shutdown pin (SHDN) high powers
on the master bias circuit, which in turn charges the
external capacitor tied to the BIAS pin using a con-
trolled current. The voltage at BIAS controls the output
power level, which ramps until the BIAS pin is internally
clamped to approximately 2.2V. The envelope ramp-
down time is controlled in a similar manner when the
SHDN
pin is pulled low.
Variable output power control over a 15dB range is also
possible by forcing the voltage on the BIAS pin exter-
nally from 0.6V to 2.4V.
During the on state (SHDN = high), the power-supply
bias current is typically 52mA with no RF applied to the
input. During the off state (SHDN = low), the supply
current is typically reduced to less than 1µA.
MAX2430
4
RFIN
6
GND1
7
VCC1
8
9
VCC2
RFOUT
10
BIAS
11–14
GND4
Note:
MAX2430IEE (PwrQSOP package) underside metal slug
must be soldered to PCB ground plane.
_______________________________________________________________________________________
5
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