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General DescriptionThe MAX9987 and MAX9988 LO buffers/splitters eachintegrate a passive two-way power splitter with high-isolation input and output buffer amplifiers. Thesebuffers are designed to provide the high output(+14dBm to +20dBm) necessary to drive the LO inputsof high-linearity passive mixers, while offering 40dBreverse isolation to prevent LO pulling. The MAX9987 isinternally matched for the cellular/GSM bands, and theMAX9988 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 30dBoutput-to-output port isolation, and are offered in 5mm 5mm 20-pin thin QFN packages with exposed paddle.
ApplicationsCellular/GSM/DCS/PCS/UMTS Base StationTx/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
Features♦ ±1dB Output Power Variation
♦ +14dBm to +20dBm Adjustable Output Power
♦ Two-Way Power Splitting
♦ 40dB Reverse Isolation
♦ More than 30dB Output-to-Output Isolation
♦ Low Output Noise: -170dBc/Hz at +17dBm
♦ 160mA Supply Current at +17dBm
♦ Isolated PLL Output (+3dBm)
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
________________________________________________________________ Maxim Integrated Products 1
MAX9987MAX9988
BIAS
BIASIN
RF LO
TO PLL PRESCALER
PLL BUFFER
INPUT AMP
OUTPUT AMP(2)
OUTPUT AMP(1)
RF INPUT(1)
IF OUTPUT(1)
PASSIVE TWO-WAYPOWER SPLITTER
IN(+7dBm)
OUTPLL(+3dBm)
OUT1(+17dBm)
OUT2(+17dBm)
BIASOUT
BIAS CONTROLNETWORK
RF INPUT(2)
IF OUTPUT(2)
Typical Operating Circuit and Block Diagram
Ordering Information
19-2416; Rev 2; 3/04
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.
PARTTEMP
RANGEPIN-PACKAGE
FREQUENCYRANGE
MAX9987ETP-T -40°C to 85°C 20 ThinQFN-EP*
700MHz to1100MHz
MAX9988ETP-T -40°C to 85°C 20 ThinQFN-EP*
1500MHz to2200MHz
*EP = Exposed paddle.
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.
VCC1, VCC2, VCC3, VCCREF to GND.................................................-0.3V to +6.0V
IN to GND...................................................-0.3V to (VCC + 0.3V)OUT1, OUT2,
OUTPLL to GND......................................-0.3V to (VCC + 0.3V)REF to GND ......................................................Source/Sink 5mAINBIAS, OUTBIAS, to GND..................................-0.3V to +0.75VPLLBIAS ......................................................................Sink 25mARF Input Power ...............................................................+20dBm
Continuous Power Dissipation (TA = +70°C)5mm 5mm 20-Pin Thin QFN (derate 20mW/°C above +70°C).............................................................1600mW
θJA....................................................................................50°C/WJunction Temperature ......................................................+150°COperating Temperature Range ...........................-40°C to +85°CStorage Temperature Range .............................-65°C to +150°CLead Temperature (soldering, 10s) .................................+300°C
DC ELECTRICAL CHARACTERISTICS—MAX9987(Typical Application Circuit, VCC = 4.75V to 5.25V, input and outputs terminated in 50Ω, TA = -40°C to +85°C. Typical specificationsare for VCC = 5.0V and TA = +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage VCC 4.75 5.00 5.25 V
Low power setting(see Table 1 for resistor values)
110
Nominal power setting(R1, R2, R4, and R5 not installed)
139 155 171Supply Current ICC
High power setting(see Table 1 for resistor values)
221
mA
DC ELECTRICAL CHARACTERISTICS—MAX9988(Typical Application Circuit, VCC = 4.75V to 5.25V, input and outputs terminated in 50Ω, TA = -40°C to +85°C. Typical specificationsare for VCC = 5.0V and TA = +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage VCC 4.75 5.00 5.25 V
Low power setting(see Table 1 for resistor values)
120
Nominal power setting(R1, R2, R4, and R5 not installed)
150 162 175Supply Current ICC
High power setting(see Table 1 for resistor values)
229
mA
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
_______________________________________________________________________________________ 3
AC ELECTRICAL CHARACTERISTICS—MAX9987(Typical Application Circuit, VCC = 4.75V to 5.25V, 50Ω environment, +4dBm < PIN < +10dBm, 700MHz < fIN < 1100MHz, TA = -40°C to +85°C, unless otherwise noted. Typical specifications are for VCC = 5.0V, PIN = +7dBm, fIN = 900MHz, and TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITSOperating Frequency f 700 1100 MHz
Low power setting, PIN = +4dBm(see Table 1 for resistor values)
14.3
Nominal power setting,+4dBm < PIN < +10dBm, 4.75V < VCC <5.25V, -40°C < TA < +85°C(R1, R2, R4, and R5 not installed)
17.3±0.8
Output Power (Main Drivers) POUTLO
High power setting, PIN = +10dBm(see Table 1 for resistor values)
19.7
dBm
Output Power (PLL Driver) POUTPLL 3.7 dBm
Input VSWR VSWRIN 1.2:1
Output VSWR VSWROUT 1.7:1
Output-Noise Power Density PNOISEVCC = 5.0V, ±100MHz offset(R1, R2, R4, and R5 not installed)
-152 dBm/Hz
OUT1 to OUT2 Isolation S23VCC = 5.0V, nominal power setting(R1, R2, R4, and R5 not installed)
45 dB
OUT2 to OUT1 Isolation S32VCC = 5.0V, nominal power setting(R1, R2, R4, and R5 not installed)
39 dB
OUT1 to RFIN Isolation S12VCC = 5.0V, nominal power setting(R1, R2, R4, and R5 not installed)
48 dB
OUT2 to RFIN Isolation S13VCC = 5.0V, nominal power setting(R1, R2, R4, and R5 not installed)
50 dB
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
4 _______________________________________________________________________________________
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Frequency f 1500 2200 MHz
Low power setting, PIN = +6dBm(see Table 1 for resistor values)
14.2
Nominal power setting,+6dBm < PIN < +12dBm, 4.75V < VCC <5.25V, -40°C < TA < +85°C(R1, R2, R4, and R5 not installed)
17.3±0.8
Output Power(Main Drivers)
POUTLO
High power setting, PIN = +12dBm(see Table 1 for resistor values)
19.5
dBm
Output Power(PLL Driver)
POUTPLL 3.6 dBm
Input VSWR VSWRIN 1.5:1
Output VSWR VSWROUT 1.4:1
Output-Noise Power Density PNOISE VCC = 5.0V, ±100MHz offset -152 dBm/Hz
OUT1 to OUT2 Isolation S23VCC = 5.0V, nominal power setting(R1, R2, R4, and R5 not installed)
33 dB
OUT2 to OUT1 Isolation S32VCC = 5.0V, nominal power setting(R1, R2, R4, and R5 not installed)
44 dB
OUT1 to RFIN Isolation S12VCC = 5.0V, nominal power setting(R1, R2, R4, and R5 not installed)
49 dB
OUT2 to RFIN Isolation S13VCC = 5.0V, nominal power setting(R1, R2, R4, and R5 not installed)
47 dB
AC ELECTRICAL CHARACTERISTICS—MAX9988(Typical Application Circuit, VCC = 4.75V to 5.25V, 50Ω environment, +6dBm < PIN < +12dBm, 1500MHz < fIN < 2200MHz, and TA = -40°C to +85°C, unless otherwise noted. Typical specifications are for VCC = 5.0V, PIN = +9dBm, fIN = 1800MHz, and TA = +25°C unless otherwise noted.) (Note 1)
Note 1: Devices are 100% DC screened and AC production tested for functionality. Data sheet typical specifications are derivedfrom the average of 30 units from a typical lot, and are tested under the conditions specified for the typical specifications.
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
_______________________________________________________________________________________ 5
SUPPLY CURRENT vs. OUTPUT POWEROUTMAIN
MAX
9987
toc0
1
OUTPUT POWER (dBm)
SUPP
LY C
URRE
NT (m
A)
20151050-5-10
145
150
155
160
165
170
180
140-15
175
TA = -40°C
TA = +25°C AND +85°C
OUTPUT POWER vs. INPUT POWEROUT1
MAX9987 toc02
INPUT POWER (dBm)
OUTP
UT P
OWER
(dBm
)
92 3-3-4
11
12
13
14
15
16
17
18
19
20
10-5 1087-2 -1 0 1 4 5 6
TA = +85°C
TA = +25°C
TA = -40°C
OUTPUT POWER vs. INPUT POWEROUT2
MAX9987 toc03
INPUT POWER (dBm)
OUTP
UT P
OWER
(dBm
)
92 3-3-4
11
12
13
14
15
16
17
18
19
20
10-5 1087-2 -1 0 1 4 5 6
TA = +85°C
TA = +25°C
TA = -40°C
OUTPUT POWER vs. INPUT POWER, OUTPLL
MAX
9987
toc0
4
INPUT POWER (dBm)
OUTP
UT P
OWER
(dBm
)
862 4-2 0-4
-4
-3
-2
-1
0
1
2
3
4
5
-5-6 10
TA = +85°C
TA = +25°C
TA = -40°C
OUTPUT POWER vs. FREQUENCY, OUT1
MAX
9987
toc0
5
OPERATING FREQUENCY (MHz)
OUTP
UT P
OWER
(dB
m)
1200800700600
15
16
17
18
20
14500
19
900 1000 1100
TA = +85°C
TA = +25°C TA = -40°C
OUTPUT POWER vs. FREQUENCY, OUT2
MAX
9987
toc0
6
OPERATING FREQUENCY (MHz)
OUTP
UT P
OWER
(dBm
)
1200800700600
15
16
17
18
20
14500
19
900 1000 1100
TA = +85°C
TA = +25°C TA = -40°C
OUTPUT POWER vs. FREQUENCY, PLL
MAX
9987
toc0
7
OPERATING FREQUENCY (MHz)
OUTP
UT P
OWER
(dBm
)
1200800700600
1
2
3
4
6
0500
5
900 1000 1100
TA = +85°CTA = +25°C
TA = -40°C
OUTPUT POWER AND SUPPLY CURRENTvs. TEMPERATURE
MAX9987 toc08
AMBIENT TEMPERATURE (°C)
OUTP
UT P
OWER
(dBm
)
806020 400-20
16.2
16.4
16.6
16.8
17.0
17.2
17.4
17.6
17.8
18.0
16.0-40
ICC
160.2
160.4
160.6
160.8
161.0
161.2
161.4
161.6
161.8
162.0
160.0
SUPP
LY C
URRE
NT (m
A)
POUT
OUTPUT POWER vs. SUPPLY VOLTAGEMAX9987 toc09
SUPPLY VOLTAGE (V)
OUT1
, OUT
2 OU
TPUT
POW
ER (
dBm
)
5.54.94.84.74.6
14.5
15.0
15.5
16.0
16.5
17.0
18.0
14.04.5
17.5 OUT2
5.0 5.1 5.2 5.3 5.4
2.5
3.0
3.5
4.0
4.5
5.0
6.0
2.0
5.5
OUT1
OUTPLL
PLL
OUTP
UT P
OWER
(dB
m)
Typical Operating Characteristics(VCC = 5.0V, nominal bias, fIN = 900MHz, PIN = +7dBm, TA = +25°C, unless otherwise noted.) (Shaded regions are outside the guaranteed operating range, and are provided for reference only.)
MAX9987
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)(VCC = 5.0V, nominal bias, fIN = 900MHz, PIN = +7dBm, TA = +25°C, unless otherwise noted.) (Shaded regions are outside theguaranteed operating range, and are provided for reference only.)
SUPPLY CURRENT vs. SUPPLY VOLTAGEM
AX99
87 to
c10
SUPPLY VOLTAGE (V)
SUPP
LY C
URRE
NT (
mA)
5.54.94.84.74.6
145
150
155
160
170
1404.5
165
5.0 5.1 5.2 5.3 5.4
PLL NOT BIASED
PLL BIASED
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX
9987
toc1
1
FREQUENCY (GHz)
GAIN
(dB)
1.00.90.80.70.6
14
15
16
17
18
19
130.5 1.1
VCC = 5.0V TA = +25°CPIN = -15dBmNOMINAL BIAS
OUT1
OUT2
INPUT RETURN LOSS vs. FREQUENCY
MAX
9987
toc1
2
FREQUENCY (GHz)
RETU
RN L
OSS
(dB)
1.11.00.90.80.70.6
-35
-30
-25
-20
-15
-10
0
-400.5
-5VCC = 5.0V TA = +25°CPIN = +7dBm
OUTPUT RETURN LOSS vs. FREQUENCY
MAX
9987
toc1
3
FREQUENCY (GHz)
RETU
RN L
OSS
(dB)
1.11.00.90.80.70.6
-18
-16
-14
-12
-10
-8
-4
-200.5
-6
VCC = 5.0V TA = +25°CPIN = +7dBm
-2
0
OUT2
OUT1
PLL
IN ISOLATION vs. FREQUENCYM
AX99
87 to
c14
FREQUENCY (GHz)
ISOL
ATIO
N (d
B)
1.11.00.90.80.70.6
-65
-60
-55
-50
-45
-40
-30
-700.5
-35
VCC = 5.0V TA = +25°CPIN = +7dBm
-25
-20
OUT2 TO IN
PLL TO IN
OUT1 TO IN
OUT1 AND OUT2 ISOLATION vs. FREQUENCY
MAX
9987
toc1
5
FREQUENCY (GHz)
ISOL
ATIO
N (d
B)
1.11.00.90.80.70.6
-65
-60
-55
-50
-45
-40
-30
-700.5
-35
VCC = 5.0V TA = +25°CPIN = +7dBm
-25
-20
OUT1 TO OUT2
OUT2 TO OUT1
PLL ISOLATION vs. FREQUENCY
MAX
9987
toc1
6
FREQUENCY (GHz)
ISOL
ATIO
N (d
B)
1.11.00.90.80.70.6
-65
-60
-55
-50
-45
-40
-30
-700.5
-35
VCC = 5.0V TA = +25°CPIN = +7dBm
-25
-20
OUT2 TO PLL
OUT1 TO PLL
PLL TO OUT_
OUTPUT NOISE POWERvs. INPUT POWER
MAX
9987
toc1
7
INPUT POWER (dBm)
NOIS
E PO
WER
(dBm
/Hz)
98765
-155
-150
-145
-140
-1604 10
±100MHz OFFSET
MAX9987
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
_______________________________________________________________________________________ 7
140
150
145
160
155
175
170
165
180
-15 -5-10 0 5 10 15 20
SUPPLY CURRENT vs. OUTPUT POWERM
AX99
88 to
c01
OUTPUT POWER (dBm)
SUPP
LY C
URRE
NT (m
A)
TA = +25°C
TA = +85°C
TA = -40°C
OUTPUT POWER vs. INPUT POWER, OUT1
MAX
9988
toc0
2INPUT POWER (dBm)
OUTP
UT P
OWER
(dBm
)
875 6-2 -1 0 1 2 3 4-4 -3
11
12
13
14
15
16
17
18
19
20
10-5 9 10
TA = -40°C
TA = +85°C
TA = +25°C
OUTPUT POWER vs. INPUT POWER, OUT2
MAX
9988
toc0
3
INPUT POWER (dBm)
OUTP
UT P
OWER
(dBm
)
875 6-2 -1 0 1 2 3 4-4 -3
11
12
13
14
15
16
17
18
19
20
10-5 9 10
TA = -40°C
TA = +25°C
TA = +85°C
-5
-3
-4
-1
-2
1
0
2
4
3
5
-6 -2 0-4 2 4 6 8 10
OUTPUT POWER vs. INPUT POWER, OUTPLL
MAX
9988
toc0
4
INPUT POWER (dBm)
OUTP
UT P
OWER
(dBm
)
TA = +25°C AND +85°C
TA = -40°C
10
13
12
11
15
14
19
18
17
16
20
1500 1600 1700 1800 1900 2000 2100 2200
OUTPUT POWER vs. FREQUENCY, OUT1
MAX
9988
toc0
5
OPERATING FREQUENCY (MHz)
OUTP
UT P
OWER
(dBm
)
TA = +85°CTA = +25°C
TA = -40°C
10
13
12
11
15
14
19
18
17
16
20
1500 1600 1700 1800 1900 2000 2100 2200
OUTPUT POWER vs. FREQUENCY, OUT2
MAX
9988
toc0
6
OPERATING FREQUENCY (MHz)
OUTP
UT P
OWER
(dBm
)
TA = +85°CTA = +25°C
TA = -40°C
0
2
1
4
3
5
6
1500 1800 19001600 1700 2000 2100 2200
OUTPUT POWER vs. FREQUENCY, OUTPLL
MAX
9988
toc0
7
OPERATING FREQUENCY (MHz)
OUTP
UT P
OWER
(dBm
)
TA = +85°C
TA = +25°C
TA = -40°C
15.0
16.416.216.015.815.615.415.2
16.816.6
17.217.0
17.4
17.817.6
18.0
OUTPUT POWER AND SUPPLY CURRENTvs. TEMPERATURE
MAX9988 toc08
AMBIENT TEMPERATURE (°C)
OUTP
UT P
OWER
(dBm
)
-40 0 20-20 40 60 80160
174172170168166164162
178176
182180
184
188186
190
SUPP
LY C
URRE
NT (m
A)
ICC
POUT
14.0
15.0
14.5
15.5
17.0
17.5
16.5
16.0
18.0
4.5 4.7 4.8 4.9 5.04.6 5.1 5.2 5.3 5.4 5.5
OUTPUT POWER vs. SUPPLY VOLTAGEMAX9988 toc09
SUPPLY VOLTAGE (V)
OUT1
, OUT
2 OU
TPUT
POW
ER (d
Bm)
2.0
3.0
2.5
3.5
5.0
5.5
4.5
4.0
6.0PL
L OU
TPUT
POW
ER (d
Bm)
OUT2
OUT1
OUTPLL
_______________________________________________________________________________________ 7
Typical Operating Characteristics (continued)(VCC = 5.0V, nominal bias, fIN = 1800MHz, PIN = +7dBm, TA = +25°C, unless otherwise noted.) (Shaded regions are outside theguaranteed operating range, and are provided for reference only.)
MAX9988
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
8 _______________________________________________________________________________________
150
165
160
155
170
175
180
4.5 4.94.84.6 4.7 5.0 5.1 5.2 5.3 5.4 5.5
SUPPLY CURRENTvs. SUPPLY VOLTAGE
MAX
9988
toc1
0
SUPPLY VOLTAGE (V)
SUPP
LY C
URRE
NT (m
A)
PLL BIASED
PLL NOT BIASED
10
12
11
14
13
17
16
15
18
1.5 1.71.6 1.8 1.9 2.0 2.1 2.2
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX
9988
toc1
1
FREQUENCY (GHz)
GAIN
(dB)
VCC = 5.0VTA = +25°CPIN = -15dBmNORMAL BIASOUT2
OUT1
-20
-16
-18
-12
-14
-8
-10
-6
1.5 1.7 1.81.6 1.9 2.0 2.1 2.2
INPUT RETURN LOSS vs. FREQUENCY
MAX
0998
8 to
c12
FREQUENCY (GHz)
RETU
RN L
OSS
(dB)
VCC = 5.0VTA = +25°CPIN = +7dBm
-40
-30
-35
-20
-25
-5
-10
-15
0
1.5 1.71.6 1.8 1.9 2.0 2.1 2.2
OUTPUT RETURN LOSS vs. FREQUENCY
MAX
9988
toc1
3
FREQUENCY (GHz)
RETU
RN L
OSS
(dB)
VCC = 5.0VTA = +25°CPIN = +7dBm
OUT2
OUT1
OUTPLL
-65
-50
-55
-60
-40
-45
-20
-25
-30
-35
-15
1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2
OUT TO IN ISOLATION vs. FREQUENCY
MAX
9988
toc1
4
FREQUENCY (GHz)
ISOL
ATIO
N (d
B)
VCC = 5.0VTA = +25°CPIN = +7dBm
OUT1 TO IN
OUT2 TO IN
PLL TO IN
-65
-50
-55
-60
-40
-45
-20
-25
-30
-35
-15
1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2
OUT TO OUT ISOLATION vs. FREQUENCY
MAX
9988
toc1
5FREQUENCY (GHz)
ISOL
ATIO
N (d
B)
VCC = 5.0VTA = +25°CPIN = +7dBm
OUT1 TO OUT2
OUT2 TO OUT1
-50
-35
-40
-45
-25
-30
-5
-10
-15
-20
0
1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2
PLL ISOLATION vs. FREQUENCY
MAX
9988
toc1
6
FREQUENCY (GHz)
ISOL
ATIO
N (d
B)
VCC = 5.0VTA = +25°CPIN = +7dBm
OUT2 TO PLL
PLL TO OUT_
OUT1 TO PLL
-140
-145
-150
-155
-1604 75 6 8 9 10
OUTPUT NOISE vs. INPUT POWER
MAX
9988
toc1
7
INPUT POWER (dBm)
OUTP
UT N
OISE
(dBm
/Hz)
±100MHz OFFSET
Typical Operating Characteristics (continued)(VCC = 5.0V, nominal bias, fIN = 1800MHz, PIN = +7dBm, TA = +25°C, unless otherwise noted.) (Shaded regions are outside theguaranteed operating range, and are provided for reference only.)
MAX9988
MA
X9
98
7/M
AX
99
88
+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
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Detailed DescriptionThe MAX9987/MAX9988 LO amplifiers/splitters eachconsist of a single input amplifier, a two-way passivepower splitter, two separate output amplifiers, as well asa third buffer amplifier to drive the LO’s PLL. The biascurrents for the amplifiers are adjustable through off-chipresistors. This allows the output level to be precision setanywhere from +14dBm to +20dBm. The PLL output ispreset to +3dBm (about 900mVP-P into 50Ω).
Power levels are typically ±1dB over the full supply, inputpower, frequency, and temperature range. Precisionpower control is achieved by internal control circuitry.Maintaining tight power control keeps the system engi-neer from over specifying the LO drive in order to guar-antee a linearity specification in the base-station mixer.
More than 40dB isolation between the LO outputs andthe input prevents VCO pulling, and the 30dB output-to-output isolation reduces branch-to-branch coupling.
The MAX9987 is specified from 700MHz to 1100MHz,and the MAX9988 is specified from 1500MHz to2200MHz. Both are offered in compact 5mm 5mm 20-pin QFN packages with exposed paddle.
Input AmplifierA single low-noise input amplifier before the passivesplitter provides gain and isolation. The compressedoutput power for this stage is controlled by the bias set-ting resistors R1 or R4 (see Typical Application Circuit).These resistors are not required for the nominal +17dBmoutput; see Table 1 for bias resistor values to obtain+14dBm to +20dBm output power.
The input is internally matched to 50Ω, and typicalVSWR is no more than 2:1 over all operating conditions.Since the input is internally biased, provide a DC blockat the input pin.
PLL Amplifier and OutputA small amount of power is tapped off from the inputamplifier’s output, and fed to a high-isolation buffer todrive the PLL output at +3dBm. If the PLL output is notrequired, it can be disabled by removing R3; disablingthe PLL output saves 12mA supply current.
Passive Two-Way SplitterThe input amplifier drives an integrated power splitter.All impedance matching between stages is on-chip, sono external tuning components are required.
Pin Description
PIN NAME FUNCTION
1, 4, 8, 9, 13,17, 18, EP
GND Ground
2 IN Input. Internally matched 50Ω RF input. AC couple to this pin.
3 VCCREFSupply. Supply connection for on-chip voltage and current references. See Applications Informationfor information on decoupling.
5 REFVoltage Reference Output. Output for on-chip 1.5V bandgap voltage reference. SeeApplications Information section for information on decoupling.
6 BIASINBias Connection for Input Buffer. Set compressed power point for input amplifier with a resistor toREF or GND. For +17dBm output power, no external biasing resistors are required. See ApplicationsInformation section for information.
7 BIASOUTBias Connection for Output Amplifiers. Set compressed power point for OUT1 and OUT2 with aresistor to REF or ground. For +17dBm output power, no external biasing resistors are required. SeeApplications Information section for information.
10 OUT2 Output 2. Internally matched 50Ω RF output. AC couple to this pin.
11, 12 VCC3 Supply. Supply connection for OUT2.
14, 15 VCC2 Supply. Supply connection for OUT1.
16 OUT1 Output 1. Internally matched 50Ω RF output. AC couple to this pin.
19 VCC1 Supply. Supply connection for input amplifier.
20 OUTPLL Output PLL. Output for driving optional external PLL.
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+14dBm to +20dBm LO Buffers/Splitterswith ±1dB Variation
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Driver Amplifiers and OutputsEach of the output amplifiers are similar to the inputamplifier, except they are biased higher to provide moreoutput power. For example, with an input power of+10dBm, the MAX9987 can deliver +20dBm at both out-puts. The bias is adjustable; see Table 1 for details.
Both RF outputs are internally matched to 50Ω, with a typical VSWR limit of 2:1. Provide DC blocking capacitorsat the outputs.
Applications InformationInput and Output Matching
All input and output matching is accomplished on-chip;no external matching circuitry is required. Use a DCblock of about 47pF (lowband) or 22pF (highband) at theinput and the outputs. Because these parts are internallybroadband matched, adjusting external component values can optimize performance for a particular band.
Input Drive LevelIn the case of the MAX9987, the typical required inputdrive level is +7dBm for +17dBm output, or +10dBm for+20dBm output. The MAX9988 uses slightly higherinput levels (see Table 1). The typical VCO cannot pro-vide sufficient drive by itself; the typical application fol-lows the VCO with attenuation (about +3dB), and thenwith a low-noise gain block. This allows the VCO todrive the MAX9987/MAX9988 input at the required levelwithout being load-pulled.
Output Drive LevelThe output drive of the MAX9987/MAX9988 is nominally+17dBm ±1dB. This is the typical application, with noexternal bias-setting resistors at INBIAS and OUTBIAS.Output power can be set from +14dBm to +20dBm byusing the bias-setting resistor values listed in Table 1.
Layout ConsiderationsA properly designed PC board is an essential part ofany RF/microwave circuit. Keep RF signal lines as shortas possible to reduce losses, radiation, and induc-tance. For best performance, route the ground pintraces directly to the exposed pad underneath thepackage. This pad must be connected to the groundplane of the board by using multiple vias under thedevice to provide the best RF/thermal conduction path.Solder the exposed pad on the bottom of the devicepackage to a PC board exposed pad.
Chip InformationTRANSISTOR COUNT: 89
PROCESS: BiCMOS
Table 1. External Resistor Values for +14dBm to +20dBm Output Power
NOMINALOUTPUT POWER
(dBm)R1 (Ω) R2 (Ω) R4 (Ω) R5 (Ω)
MAX9987INPUT DRIVE
(dBm)
MAX9988INPUT DRIVE
(dBm)
+20 1.35k 2.0k Open Open 10 ±3 12 ±3
+19 2.2k 3.0k Open Open 9 ±3 11 ±3
+18 5.0k 6.0k Open Open 8 ±3 10 ±3
+17 Open Open Open Open 7 ±3 9 ±3
+16 Open Open 1.8k 3.0k 6 ±3 8 ±3
+15 Open Open 0.9k 1.1k 5 ±3 7 ±3
+14 Open Open 0.6k 0.6k 4 ±3 6 ±3
Table 2. Component Values for TypicalApplication Circuit
COMPONENT VALUE
DESIGNATION MAX9987(LOWBAND)
MAX9988(HIGHBAND)
C1, C6 100nF 100nF
C3 100pF 100nF
C2, C4, C5, C7, C8,C9, C12, C13, C14
47pF 22pF
C10, C11 5pF 10pF
R1, R2, R4, R5 See Table 1 See Table 1
R3 100Ω 100Ω
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MAX9987MAX9988
1
2
3
4
5
6 7 8 9 10
20 19 18 17 16
15
14
13
12
11BIAS
R4* R5*
GND
BIAS
OUT
BIAS
IN
GND
GND
VCC1
OUTP
LL
GND
OUT2
OUT1
R2*
C8
C13
C10
VCC3
VCC3
VCC2
VCC2
GND
GND
IN
VCCREF
GND
REF
C9
5.0V
C1
R3100Ω
C2
C6 C7
C14
C5
OUT TO PLL(+3dBm)
INPUT FROM LO
5.0V
5.0V
5.0V
TO OUTPUT 2
TO OUTPUT 1
R1*
C11 C12
C3 C4
5.0V
* FOR THESE VALUES, SEE TABLE 1. FOR CAPACITOR VALUES, SEE TABLE 2.
EXPOSED PAD
Typical Application Circuit/Pin Configuration
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Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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.)
32L
QFN
.EP
S