19-2416; Rev 0; 4/02
+14dBm to +20dBm LO Buffers/Splitters
with ±1dB Variation
General Description
The MAX9987 and MAX9988 LO buffers/splitters each
integrate a passive two-way power splitter with high-
isolation input and output buffer amplifiers. These
buffers are designed to provide the high output
(+14dBm to +20dBm) necessary to drive the LO inputs
of high-linearity passive mixers, while offering 40dB
reverse isolation to prevent LO pulling. The MAX9987 is
internally matched for the cellular/GSM bands, and the
MAX9988 is matched for the DCS/PCS/UMTS bands.
The typical application circuit provides a nominal
+17dBm output power with ±1dB variation over supply,
temperature, and input power. With two optional resis-
tors, the output power can be precision set from
+14dBm to +20dBm. The devices offer more than 30dB
output-to-output port isolation, and are offered in 5mm
✕
5mm 20-pin QFN packages with exposed paddle.
o
±1dB Output Power Variation
o
+14dBm to +20dBm Adjustable Output Power
o
Two-Way Power Splitting
o
40dB Reverse Isolation
o
More than 30dB Output-to-Output Isolation
o
Low Output Noise: -170dBc/Hz at +17dBm
o
160mA Supply Current at +17dBm
o
ESD Protection
o
Isolated PLL Output (+3dBm)
Features
MAX9987/MAX9988
Applications
Cellular/GSM/DCS/PCS/UMTS Base Station
Tx/Rx LO Drive
Base Station Main and Diversity Channels
Coherent Receivers
ISM Wireless LAN
Wireless Local Loop
Local Multipoint Distribution Service
Point-to-Point Systems
*EP =
Exposed paddle
MAX9987EGP
MAX9988EGP
PART
Ordering Information
TEMP
RANGE
-40°C to 85°C
-40°C to 85°C
PIN-
PACKAGE
20 QFN-EP*
20 QFN-EP*
FREQUENCY
RANGE
700MHz to
1100MHz
1500MHz to
2200MHz
Typical Operating Circuit and Block Diagram
PLL BUFFER
TO PLL
PRESCALER
OUTPLL
(+3dBm)
OUTPUT AMP
(1)
OUT1
(+17dBm)
RF INPUT
(1)
MAX9987
MAX9988
IF OUTPUT
(1)
IN
(+7dBm)
RF LO
INPUT AMP
PASSIVE TWO-WAY
POWER SPLITTER
BIAS
OUTPUT AMP
(2)
BIASIN
BIASOUT
OUT2
(+17dBm)
RF INPUT
(2)
IF OUTPUT
(2)
BIAS
CONTROL
NETWORK
________________________________________________________________
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.
+14dBm to +20dBm LO Buffers/Splitters
with ±1dB Variation
MAX9987/MAX9988
ABSOLUTE MAXIMUM RATINGS
VCC1, VCC2, VCC3,
VCCREF to GND.................................................-0.3V to +6.0V
IN to GND ...................................................-0.3V to (V
CC
+ 0.3V)
OUT1, OUT2,
OUTPLL to GND ......................................-0.3V to (V
CC
+ 0.3V)
REF to GND ......................................................Source/Sink 5mA
INBIAS, OUTBIAS, to GND..................................-0.3V to +0.75V
PLLBIAS ......................................................................Sink 25mA
RF Input Power ...............................................................+20dBm
Continuous Power Dissipation (T
A
= +70°C)
5mm
✕
5mm 20-Pin QFN (derate 20mW/°C
above +70°C).............................................................1600mW
θ
JA
....................................................................................50°C/W
Junction Temperature ......................................................+150°C
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°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.
DC ELECTRICAL CHARACTERISTICS—MAX9987
(Typical Application Circuit, V
CC
= 4.75V to 5.25V, input and outputs terminated in 50Ω, T
A
= -40°C to +85°C. Typical specifications
are for V
CC
= 5.0V and T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage
SYMBOL
V
CC
Low power setting
(see Table 1 for resistor values)
Supply Current
I
CC
Nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
High power setting
(see Table 1 for resistor values)
139
CONDITIONS
MIN
4.75
TYP
5.00
110
155
221
171
mA
MAX
5.25
UNITS
V
DC ELECTRICAL CHARACTERISTICS—MAX9988
(Typical Application Circuit, V
CC
= 4.75V to 5.25V, input and outputs terminated in 50Ω, T
A
= -40°C to +85°C. Typical specifications
are for V
CC
= 5.0V and T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage
SYMBOL
V
CC
Low power setting
(see Table 1 for resistor values)
Supply Current
I
CC
Nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
High power setting
(see Table 1 for resistor values)
150
CONDITIONS
MIN
4.75
TYP
5.00
120
162
229
175
mA
MAX
5.25
UNITS
V
2
_______________________________________________________________________________________
+14dBm to +20dBm LO Buffers/Splitters
with ±1dB Variation
AC ELECTRICAL CHARACTERISTICS—MAX9987
(Typical Application Circuit, V
CC
= 4.75V to 5.25V, 50Ω environment, +4dBm < P
IN
< +10dBm, 700MHz < f
IN
< 1100MHz,
T
A
= -40°C to +85°C, unless otherwise noted. Typical specifications are for V
CC
= 5.0V, P
IN
= +7dBm, f
IN
= 900MHz, and
T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Operating Frequency
SYMBOL
f
CONDITIONS
Low power setting, P
IN
= +4dBm
(see Table 1 for resistor values)
Nominal power setting,
+4dBm < P
IN
< +10dBm, 4.75V < V
CC
<
5.25V, -40°C < T
A
< +85°C
(R
1
, R
2
, R
4
, and R
5
not installed)
High power setting, P
IN
= +10dBm
(see Table 1 for resistor values)
Output Power (PLL Driver)
Input VSWR
Output VSWR
Output-Noise Power Density
OUT1 to OUT2 Isolation
OUT2 to OUT1 Isolation
OUT1 to RFIN Isolation
OUT2 to RFIN Isolation
P
OUTPLL
VSWR
IN
VSWR
OUT
P
NOISE
S23
S32
S12
S13
V
CC
= 5.0V, ±100MHz offset
(R
1
, R
2
, R
4
, and R
5
not installed)
V
CC
= 5.0V, nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
V
CC
= 5.0V, nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
V
CC
= 5.0V, nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
V
CC
= 5.0V, nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
MIN
700
TYP
MAX
1100
UNITS
MHz
MAX9987/MAX9988
14.3
Output Power (Main Drivers)
P
OUTLO
17.3
±0.8
dBm
19.7
3.7
1.2:1
1.7:1
-152
45
39
48
50
dBm/Hz
dB
dB
dB
dB
dBm
_______________________________________________________________________________________
3
+14dBm to +20dBm LO Buffers/Splitters
with ±1dB Variation
MAX9987/MAX9988
AC ELECTRICAL CHARACTERISTICS—MAX9988
(Typical Application Circuit, V
CC
= 4.75V to 5.25V, 50Ω environment, +6dBm < P
IN
< +12dBm, 1500MHz < f
IN
< 2200MHz, and
T
A
= -40°C to +85°C, unless otherwise noted. Typical specifications are for V
CC
= 5.0V, P
IN
= +9dBm, f
IN
= 1800MHz, and
T
A
= +25°C unless otherwise noted.) (Note 1)
PARAMETER
Operating Frequency
SYMBOL
f
Low power setting, P
IN
= +6dBm
(see Table 1 for resistor values)
Output Power
(Main Drivers)
Nominal power setting,
+6dBm < P
IN
< +12dBm, 4.75V < V
CC
<
5.25V, -40°C < T
A
< +85°C
(R
1
, R
2
, R
4
, and R
5
not installed)
High power setting, P
IN
= +12dBm
(see Table 1 for resistor values)
Output Power
(PLL Driver)
Input VSWR
Output VSWR
Output-Noise Power Density
OUT1 to OUT2 Isolation
OUT2 to OUT1 Isolation
OUT1 to RFIN Isolation
OUT2 to RFIN Isolation
P
OUTPLL
VSWR
IN
VSWR
OUT
P
NOISE
S23
S32
S12
S13
V
CC
= 5.0V, ±100MHz offset
V
CC
= 5.0V, nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
V
CC
= 5.0V, nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
V
CC
= 5.0V, nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
V
CC
= 5.0V, nominal power setting
(R
1
, R
2
, R
4
, and R
5
not installed)
CONDITIONS
MIN
1500
14.2
TYP
MAX
2200
UNITS
MHz
P
OUTLO
17.3
±0.8
dBm
19.5
3.6
1.5:1
1.4:1
-152
33
44
49
47
dBm/Hz
dB
dB
dB
dB
dBm
Note 1:
Devices are 100% DC screened and AC production tested for functionality. Data sheet typical specifications are derived
from the average of 30 units from a typical lot, and are tested under the conditions specified for the typical specifications.
4
_______________________________________________________________________________________
+14dBm to +20dBm LO Buffers/Splitters
with ±1dB Variation
Typical Operating Characteristics
(V
CC
= 5.0V, nominal bias, f
IN
= 900MHz, P
IN
= +7dBm, T
A
= +25°C, unless otherwise noted.) (Shaded regions are outside the
guaranteed operating range, and are provided for reference only.)
MAX9987/MAX9988
MAX9987
SUPPLY CURRENT vs. OUTPUT POWER
OUTMAIN
MAX9987 toc01
OUTPUT POWER vs. INPUT POWER
OUT1
20
19
18
OUTPUT POWER (dBm)
17
16
15
14
13
12
11
10
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
OUTPUT POWER (dBm)
MAX9987 toc02
OUTPUT POWER vs. INPUT POWER
OUT2
20
19
18
17
16
15
14
13
12
11
10
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
MAX9987 toc03
180
175
SUPPLY CURRENT (mA)
170
165
160
155
T
A
= -40°C
150
145
140
-15
-10
-5
0
5
10
15
T
A
= +25°C AND +85°C
20
OUTPUT POWER (dBm)
-5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
INPUT POWER (dBm)
-5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
INPUT POWER (dBm)
OUTPUT POWER vs. INPUT POWER, OUTPLL
MAX9987 toc04
OUTPUT POWER vs. FREQUENCY, OUT1
MAX9987 toc05
OUTPUT POWER vs. FREQUENCY, OUT2
MAX9987 toc06
5
4
3
OUTPUT POWER (dBm)
2
1
0
-1
-2
-3
-4
-5
-6
-4
-2
0
2
4
6
8
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
20
19
OUTPUT POWER (dBm)
T
A
= +25°C
18
17
16
15
14
T
A
= +85°C
20
19
OUTPUT POWER (dBm)
18
17
T
A
= +85°C
16
15
14
T
A
= -40°C
T
A
= +25°C
T
A
= -40°C
10
500
600
700
800
900 1000 1100 1200
500
600
700
800
900 1000 1100 1200
INPUT POWER (dBm)
OPERATING FREQUENCY (MHz)
OPERATING FREQUENCY (MHz)
OUTPUT POWER vs. FREQUENCY, PLL
MAX9987 toc07
OUTPUT POWER AND SUPPLY CURRENT
vs. TEMPERATURE
18.0
17.8
17.6
OUTPUT POWER (dBm)
17.4
17.2
17.0
16.8
16.6
16.4
16.2
P
OUT
I
CC
MAX9987 toc08
OUTPUT POWER vs. SUPPLY VOLTAGE
162.0
OUT1, OUT2 OUTPUT POWER (dBm)
161.8
SUPPLY CURRENT (mA)
161.6
161.4
161.2
161.0
160.8
160.6
160.4
160.2
160.0
18.0
17.5
17.0
16.5
16.0
15.5
15.0
14.5
14.0
4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
SUPPLY VOLTAGE (V)
OUTPLL
OUT2
OUT1
MAX9987 toc09
6
5
OUTPUT POWER (dBm)
4
3
2
1
0
500
600
700
800
T
A
= -40°C
T
A
= +25°C T = +85°C
A
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
PLL OUTPUT POWER (dBm)
900 1000 1100 1200
16.0
-40
-20
0
20
40
60
80
AMBIENT TEMPERATURE (°C)
OPERATING FREQUENCY (MHz)
_______________________________________________________________________________________
5
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