MAXIM MAX2251EBE

19-1773; Rev 2; 2/03
KIT
ATION
EVALU
E
L
B
AVAILA
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
Features
♦ Ultra-Compact 4
2.06mm) CSP
♦ On-Chip Power Detector
♦ ICC < 1µA in Shutdown Mode
♦ +2.8V to +4.5V True Single-Supply Operation
♦ ±0.9dB Gain Variation from TA = -40°C to +85°C
♦ Current Adjustable with PDM or DAC Signal
♦ No External Logic Interface Circuitry Required
Ordering Information
Cellular-Band TDMA/AMPS Dual-Mode Phones
PART
2-Way Pagers
(2.06mm
✕
♦ High Efficiency—41% at +30dBm POUT (TDMA)
(typ)
________________________Applications
PA Modules
✕4
TEMP
RANGE
PINPACKAGE
TOP MARK
2251
EBE
MAX2251EBE -40°C to +85°C 4 × 4 UCSP
_ _ _ (LOT #)
_ _ _ (DATE CODE)
Cordless Phones
Typical Operating Circuit appears at end of data sheet.
Pin Configuration
TOP VIEW
MAX2251
PIN A1
INDICATOR
BIAS2
GND
GND
GND
A1
A2
A3
A4
POWER
DETECTOR
B1
B2
B3
B4
PD_OUT
GND
OUT
OUT
BIAS1
GND
VCC
GND
C1
C2
C3
C4
LOGIC AND
BIAS
D1
D2
D3
D4
VCC
IN
SHDN
MODE
________________________________________________________________ Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX2251
General Description
The MAX2251 low-voltage linear power amplifier (PA) is
designed for TDMA/AMPS dual-mode phone applications. The device is packaged in an ultra-compact
(2.06mm ✕ 2.06mm) chip-scale package (CSP), and
delivers over +30dBm of linear power in TDMA operation. An on-chip shutdown feature reduces operating
current to 1µA (typ), eliminating the need for an external
supply switch.
The MAX2251 does not need an external reference voltage, and requires only a few external matching components and no bias circuitry. Another feature of this
device is the use of external bias resistors, eliminating
wasted “safety-margin” current. This feature also allows
current throttleback at lower output power levels, thereby maintaining the highest possible efficiency at all
power levels.
MAX2251
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..........................................................-0.3V to +4.5V
SHDN, MODE to GND ................................-0.3V to (VCC + 0.3V)
BIAS_ to GND.............................................-0.3V to (VCC + 0.3V)
RF Input Power ...............................................................+10dBm
Continuous Power Dissipation (TA = +70°C)
4 ✕ 4 UCSP (derate 80mW/°C above +70°C) ....................4W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Thermal Resistance from Junction to Backside.................1°C/W
Thermal Resistance from Junction to Ambient
(using MAX2251 EV kit)...............................................40°C/W
Storage Temperature Range .............................-65°C to +150°C
Bump Reflow Temperature .............................................+235°C
Continuous Operating Lifetime ...................10 yrs ✕ 0.92(TA - 45°C)
(At POUT = +32dBm, for Operating Temperature, TA ≥ 45°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
(VCC = +2.8V to +4.5V, no RF signal applied, SHDN = high, TA = -40°C to +85°C, unless otherwise noted. Typical values are measured at VCC = +3.3V and TA = +25°C.)
PARAMETER
Idle Supply Current
CONDITIONS
MIN
MODE = high
Logic High Threshold
TYP
MAX
UNITS
205
255
mA
2.0
V
Logic Low Threshold
Shutdown Supply Current
0.8
SHDN = MODE =
GND
VCC = +2.8V to +4.0V
0.6
10
VCC = +4.5V
60
120
Logic High Input Current
Logic Low Input Current
2
-1
_______________________________________________________________________________________
V
µA
5
µA
+1
µA
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
(MAX2251 EV kit, fIN = 824MHz to 849MHz, VCC = VMODE = V SHDN = +3.3V, 50Ω system, NADC modulation, duty cycle = 100%,
TA = +25°C, unless otherwise noted. Typical values are at fIN = 836MHz, TA = +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN
-4.5σ
Frequency Range (Note 2)
VMODE = VCC or GND
824
Power Gain
POUT = +30dBm
25.7
26.1
Extreme Condition Power Gain
TA = -40°C to +85°C, POUT = +30dBm
24.8
25.2
Output Power
VCC = +3.3V, meets ACPR
specifications
Adjacent/Alternate-Channel
Power Ratio
fOFFSET = 30/60kHz in
25kHz bandwidth
TYP
4.5σ
MAX
UNITS
849
MHz
27.8
dB
dB
dBm
30
TA = +25oC
-29.3/
-47.5
TA = +85°C
-28/
-48
-27.4/
-45.4
-27/
-44.6
dBc
AMPS Output Power
VMODE = VCC, PIN = +8dBm single tone
Power-Added Efficiency
POUT = +30dBm
AMPS Power-Added Efficiency
PIN = +8dBm single tone at 836MHz
31.8
32
dBm
41.2
%
51
Turn-On Time (Note 3)
Input VSWR
%
2
5
1.2:1
1.76:1
µs
Maximum Nonharmonic
Spurious Due to Load
Mismatch
VCC = +2.8V to +4.5V, all input power
levels, VSWR = 4:1 all phase angle,
TA = -40°C to +85°C
Noise Power
fRF = 849MHz, noise measured at
869MHz, POUT = +30dBm
-121
dBm/
Hz
AMPS Noise Power
fRF = 836MHz, noise measured at
881MHz, POUT = +31dBm
-141
dBm/
Hz
45
dBc
29.4
dB
-55
Harmonic Suppression (Note 4)
Power Detector Range
(Note 5)
Power Detector Settling Time
(Note 6)
CDET = 4700pF
27
2
3
dBc
µs
Guaranteed by design and characterization.
Operation outside the frequency range is possible, but has not been characterized.
Time when V SHDN transitions to VCC until POUT is within 1dB of its final mean power.
Harmonics are measured on the MAX2251 EV kit. The output matching provides some harmonic attenuation in addition to the
rejection provided by the IC. The combined suppression is specified.
Note 5: The range is defined by the difference between the rated linear output power and the output power that corresponds to
VPD = 0.57V.
Note 6: Time from when V SHDN transitions high until detector output reaches within 10% of its final value.
Note 1:
Note 2:
Note 3:
Note 4:
_______________________________________________________________________________________
3
MAX2251
AC CHARACTERISTICS, TDMA OPERATION
Typical Operating Characteristics
(MAX2251 EV kit, VCC = VMODE = V SHDN = +3.3V, fIN = 836MHz, TDMA modulation, TA = +25°C, unless otherwise noted.)
TA = +25°C
10
5
200
150
TA = +25°C
TA = -40°C
100
50
TA = -40°C
0
4.5
TA = +25°C
400
300
TA = -40°C
200
0
3.6
2.8
SUPPLY VOLTAGE (V)
4.5
2.8
GAIN vs. OUTPUT POWER
30
MAX2251-05
30
MAX2251-04
WITHOUT THROTTLEBACK
28
28
100
26
TA = +85°C
TA = -40°C
24
22
50
-10
-5
0
5
15
GAIN vs. FREQUENCY
MAX2251-07
30
28
28
26
26
24
20
25
30
10
15
20
GAIN vs. FREQUENCY
GAIN vs. FREQUENCY AMPS
VCC = VMODE = VSHDN = +2.8V
POUT = +28dBm
34
TA = -40°C
24
30
POUT = +31dBm
32
GAIN (dB)
GAIN (dB)
TA = +25°C
25
OUTPUT POWER (dBm)
VMODE = GND
30
TA = +85°C
VCC = +4.5V
OUTPUT POWER (dBm)
OUTPUT POWER (dBm)
POUT = +30dBm
VCC = +3.3V
20
10
10
VCC = +2.8V
26
22
20
0
30
TA = +25°C
GAIN (dB)
GAIN (dB)
200
WITH THROTTLEBACK (MAINTAIN
ACPR = -29dBc, ALT <-50dBc)
4.5
SUPPLY VOLTAGE (V)
GAIN vs. OUTPUT POWER
300
150
3.6
SUPPLY VOLTAGE (V)
SUPPLY CURRENT
vs. OUTPUT POWER
250
TA = +85°C
500
100
0
3.6
2.8
SUPPLY CURRENT (mA)
MAX2251-02
250
600
MAX2251-06
15
TA = +85°C
MAX2251-09
20
300
VMODE = GND
NO INPUT DRIVE
700
QUIESCENT CURRENT (mA)
TA = +85°C
25
800
MAX2251-08
SHUTDOWN CURRENT (nA)
30
NO INPUT DRIVE
350
QUIESCENT CURRENT (mA)
VSHDN = VMODE = GND
NO INPUT DRIVE
35
400
MAX2251-01
40
QUIESCENT CURRENT
vs. SUPPLY VOLTAGE
MAX2251-03
QUIESCENT CURRENT
vs. SUPPLY VOLTAGE
SHUTDOWN vs. SUPPLY VOLTAGE
GAIN (dB)
MAX2251
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
24
28
26
VMODE = VCC
24
22
22
22
20
20
824
829
834
839
FREQUENCY (MHz)
4
844
849
20
824
829
834
839
FREQUENCY (MHz)
844
849
824
829
834
839
FREQUENCY (MHz)
_______________________________________________________________________________________
844
849
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
44
30
42
25
20
TA = +85°C
34
5
32
VCC = +2.8V
PO = +28dBm
TA = +25°C
26
28
30
30
824
829
OUTPUT POWER (dBm)
839
844
824
849
50
-30
ACPR/ALT (dBc)
40
30
20
POUT = +30dBm
10
ACPR
TA = +25°C
-35
-40
ALT
TA = +85°C
-45
ACPR
TA = +85°C
ALT
TA = +25°C
28
30
32
829
OUTPUT POWER (dBm)
-100
MAX2251-16
fIN = 836MHz
-25
-110
NOISE POWER (dBm/Hz)
-30
-35
ACPR
-45
ALT
834
839
844
24
26
OUTPUT POWER (dBm)
ALT
824
829
POUT = +30dBm
TA = -40°C
fIN = 849MHz
-130
-140
fIN = 824MHz
-150
28
30
839
844
849
NOISE POWER vs. FREQUENCY AMPS
fIN = 836MHz
-120
834
FREQUENCY (MHz)
-100
-110
POUT = +32dBm
TA = -40°C
-120
fIN = 849MHz
-130
-140
fIN = 836MHz
fIN = 824MHz
-150
-160
-170
-60
22
-45
849
-160
-55
20
ACPR
-40
NOISE POWER vs. FREQUENCY
ACPR/ALT vs. OUTPUT POWER
-50
-35
FREQUENCY (MHz)
-20
-40
VSHDN = VCC = +2.8V
POUT = +28dBm
-55
824
NOISE POWER (dBm/Hz)
26
849
-50
MAX2251-17
24
844
-30
-55
22
839
ACPR/ALT vs. FREQUENCY
-25
-50
0
834
FREQUENCY (MHz)
ACPR/ALT vs. FREQUENCY
-25
MAX2251-13
VMODE = VCC
20
829
FREQUENCY (MHz)
POWER-ADDED EFFICIENCY
vs. OUTPUT POWER, AMPS
60
834
ACPR/ALT (dBc)
24
38
32
MAX2251-14
22
40
34
30
20
VMODE = GND
42
36
36
0
PAE (%)
44
40
10
VMODE = VCC
46
TA = +25°C
38
15
ACPR/ALT (dBc)
TA = -40°C
POUT = +31dBm
48
MAX2251-15
35
50
MAX2251-18
46
PAE (%)
40
POUT = +30dBm
PAE (%)
48
MAX2251-11
45
PAE (%)
50
MAX2251-10
50
POWER-ADDED EFFICIENCY
vs. FREQUENCY, AMPS
POWER-ADDED EFFICIENCY
vs. FREQUENCY
MAX2251-12
POWER-ADDED EFFICIENCY
vs. OUTPUT POWER
-170
869
874
879
884
FREQUENCY (MHz)
889
894
869
874
879
884
889
894
FREQUENCY (MHz)
_______________________________________________________________________________________
5
MAX2251
Typical Operating Characteristics (continued)
(MAX2251 EV kit, VCC = VMODE = V SHDN = +3.3V, fIN = 836MHz, TDMA modulation, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(MAX2251 EV kit, VCC = VMODE = V SHDN = +3.3V, fIN = 836MHz, TDMA modulation, TA = +25°C, unless otherwise noted.)
EVM vs. FREQUENCY
EVM (% RMS)
4
3
2
3
TA = +85°C
TA = +25°C
2
1
1
0
0
20
22
24
26
28
30
829
834
839
MAX2251-21
TA = +25°C
1.5
1.0
TA = +85°C
0.5
844
0
849
5
TA = -40°C
TA = +25°C
1.5
1.0
TA = +85°C
0.5
0
3.0
POWER DETECTOR VOLTAGE (V)
2.0
10
fIN = 836MHz SINGLE-TONE SINE WAVE
VSHDN = VCC = +3.3V
VMODE = VCC
2.5
2.0
TA = -40°C
1.5
TA = +25°C
1.0
TA = +85°C
0.5
0
0
5
10
15
20
OUTPUT POWER (dBm)
25
30
15
20
OUTPUT POWER (dBm)
POWER DETECTOR vs. OUTPUT POWER
MAX2251-22
POWER DETECTOR VOLTAGE (V)
VMODE = GND
fIN = 836MHz SINGLE-TONE SINE WAVE
2.5
TA = -40°C
2.0
FREQUENCY (MHz)
POWER DETECTOR vs. OUTPUT POWER
3.0
2.5
0
824
OUTPUT POWER (dBm)
6
3.0
MAX2251-23
4
POWER DETECTOR vs. OUTPUT POWER
POUT = +30dBm
VSHDN = VMODE = VCC = +3.3V
POWER DETECTOR VOLTAGE (V)
MAX2251-19
5
MAX2251-20
EVM vs. OUTPUT POWER
5
EVM (% RMS)
MAX2251
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
0
5
10
15
20
25
30
OUTPUT POWER (dBm)
_______________________________________________________________________________________
25
30
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
PIN
NAME
FUNCTION
A1
BIAS2
Second Stage Bias Control. Connect an 11kΩ resistor to GND to set the bias current for the second
stage of the PA.
A2, A3, A4,
B2, C2, C4
GND
Ground. Connect to the PC board ground plane with as low an inductance path as possible.
B1
PD_OUT
B3, B4
OUT
C1
BIAS1
First Stage Bias Control. Connect an external 47.5kΩ resistor to ground to set the bias current for
the driver stage.
C3
VCC
Driver Stage Supply Voltage. Connect a pullup inductor to VCC. The pullup inductor can be a PC
board trace.
D1
VCC
Supply Voltage. Bypass to ground with 100pF and 0.01µF capacitors.
D2
IN
D3
SHDN
Shutdown Input. Drive logic low to place the device in shutdown mode. Drive logic high for normal
operation.
D4
MODE
Mode Selection Input. Drive logic high for TDMA/AMPS mode. Drive logic low for higher gain AMPS
operation.
Power Detector Output. This output is a DC voltage indicating the PA output power. Connect a
capacitor to set time constant. The settling time is typically 2µs with a 4700pF capacitor.
RF Output. Connect a pullup high-Q inductor to VCC. Requires matching network. Connect B3 and
B4 together.
RF Input. Requires a highpass L-section impedance matching network.
Detailed Description
The MAX2251 is a linear PA intended for TDMA/AMPS
dual-mode applications. The PA is fully characterized in
the 824MHz to 849MHz U.S. cellular band. The PA consists of a driver stage and an output stage; both are
independently biased using external resistors. The
MAX2251 also features an integrated power detector.
Bias Control
External resistors connected to C1 and A1 independently set the bias currents of the driver and output
stages, respectively. An internal bandgap reference
fixes the voltages at C1 and A1. RBIAS1 is typically
47.5kΩ and RBIAS2 is typically 11kΩ. The bias current
can be dynamically adjusted by summing a current into
the bias pin of interest with an external source such as
a DAC. See the Typical Operating Circuit. The Typical
Operating Characteristics graph, Supply Current vs.
Output Power, demonstrates the current saving with
throttleback at low-output power levels.
Power Detector
The on-chip power detector monitors the output power.
The power detector outputs a voltage proportional to
the output power. Connect a filter capacitor from
PD_OUT to GND to set the power detector time con-
stant. The integrated power detector eliminates the
need for an external detector circuit.
Applications Information
External Matching
The MAX2251 requires input, interstage, and output
matching circuits for proper operation. See the Typical
Operating Circuit for suggested component values.
Use high-quality components for L2 and C12 in the output-matching circuit for highest efficiency. The
MAX2251 EV kit uses a trace as a pullup inductor
(approximately 2nH) for the interstage matching.
Mode Selection
MAX2251 features two modes of operation: high-linear
mode and high-gain mode. For TDMA operation, drive
MODE high or connect to VCC. For AMPS operation,
drive MODE high for best PAE, or drive MODE low for
best gain.
Layout and Thermal Management Issues
The MAX2251 EV kit serves as a layout guide. Use controlled impedance lines on all high-frequency inputs
and outputs. Connect GND to the PC board ground
plane with as low inductance path as possible. The
GND pins also serve as heat sinks. Connect all GND
_______________________________________________________________________________________
7
MAX2251
Pin Description
MAX2251
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
pins directly to the topside RF ground. On boards
where the ground plane is not on the component side,
connect all GND pins to the ground plane with plated
through holes, close to the package. PC board traces
connecting the GND pins also serve as heat sinks.
Make sure that the traces are sufficiently wide.
UCSP Reliability
The ultra-chip-scale package (UCSP) represents a
unique packaging form factor that may not perform
equally to a packaged product through traditional
mechanical reliability tests. CSP reliability is integrally
linked to the user’s assembly methods, circuit board
material, and usage environment. The user should closely
review these areas when considering use of a CSP.
Performance through Operating Life Test and Moisture
Resistance remains uncompromised as it is primarily
determined by the wafer-fabrication process.
8
Mechanical stress performance is a greater consideration
for a CSP. CSPs are attached through direct solder contact to the user’s PC board, foregoing the inherent stress
relief of a packaged-product lead frame. Solder joint contact integrity must be considered. Testing done to characterize the CSP reliability performance shows that it is
capable of performing reliably through environmental
stresses. Users should also be aware that, as with any
interconnect system there are electro-migration-based
current limits that, in this case, apply to the maximum
allowable current in the bumps. Reliability is a function of
this current, the duty cycle, lifetime, and bump temperature. See the Absolute Maximum Ratings section of the
data sheet for any specific limitations, listed under
Continuous Operating Lifetime. Results of environmental
stress tests and additional usage data and recommendations are detailed in the UCSP application note, which
can be found on Maxim’s website at www.maxim-ic.com.
_______________________________________________________________________________________
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
TOP VIEW
OPTIONAL BIAS CURRENT
THROTTLEBACK CONTROL
DAC
RTB1
RTB2
MAX2251
PIN A1
INDICATOR
VCC
R4
11k
BIAS2
GND
GND
GND
A1
A2
A3
A4
L2
7.15nH
POWER
DETECTOR
W = 85
L = 315
GND
B1
C9
4700pF
C7
0.01µF
B2
PD_OUT
B3
B4
OUT
OUT
BIAS1
GND
VCC
GND
C1
C2
C3
C4
C14
4.7pF
C13
220pF
RFOUT
C12
10pF
W = 12
L = 125
FERRITE
BEAD
R3
47.5k
VCC
C10
0.01µF
C11
100pF
LOGIC AND
BIAS
VCC
IN
D1
D2
C6
100pF
MODE
D3
D4
W=3
L = 76
W = 35
L = 187
VCC
C5
100pF
C4
0.01µF
SHDN
C3
9pF
RFIN
L1
4.7nH
W = 18
L = 80
W = 18
L = 150
SHUTDOWN
LOGIC INPUT
MODE SELECT
INPUT
ALL TRANSMISSION LINE UNITS ARE IN MILS.
_______________________________________________________________________________________
9
MAX2251
Typical Operating Circuit
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
16L,UCSP.EPS
MAX2251
+2.8V, Single-Supply,
Cellular-Band Linear Power Amplifier
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2003 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.