MAXIM MAX9987, MAX9988 Technical data

General Description

The MAX9987 and MAX9988 LO buffers/splitters each
integrate a passive two-way power splitter with high­isolation 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 resis­tors, 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 thin QFN packages with exposed paddle.

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

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)

MAX9987/MAX9988

+14dBm to +20dBm LO Buffers/Splitters

with ±1dB Variation

________________________________________________________________ Maxim Integrated Products 1

MAX9987
MAX9988

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-WAY

POWER SPLITTER

IN

(+7dBm)

OUTPLL

(+3dBm)

OUT1
(+17dBm)

OUT2
(+17dBm)

BIASOUT

BIAS
CONTROL
NETWORK

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.

PART

TEMP

RANGE

PIN-

FREQUENCY

RANGE

MAX9987ETP-T

20 Thin

700MHz to

1100MHz

MAX9988ETP-T

20 Thin

1500MHz to

2200MHz

*EP = Exposed paddle.

PACKAGE

-40°C to 85°C

-40°C to 85°C

QFN-EP*

QFN-EP*

MAX9987/MAX9988

+14dBm to +20dBm LO Buffers/Splitters
with ±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 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.

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 Thin QFN (derate 20mW/°C

above +70°C).............................................................1600mW

θJA....................................................................................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

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 specifications
are for V

CC

= 5.0V and TA= +25°C.) (Note 1)

PARAMETER

CONDITIONS

UNITS

Supply Voltage V

CC

V

Low power setting
(see Table 1 for resistor values)

Nominal power setting
(R

1

, R2, R4, and R5 not installed)

171Supply Current I

CC

High power setting
(see Table 1 for resistor values)

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 specifications
are for V

CC

= 5.0V and TA= +25°C.) (Note 1)

PARAMETER

CONDITIONS

UNITS

Supply Voltage V

CC

V

Low power setting
(see Table 1 for resistor values)

Nominal power setting
(R

1

, R2, R4, and R5 not installed)

175Supply Current I

CC

High power setting
(see Table 1 for resistor values)

mA

SYMBOL

MIN TYP MAX

4.75 5.00 5.25

110

SYMBOL

139 155

221

MIN TYP MAX

4.75 5.00 5.25

120

150 162

229

MAX9987/MAX9988

+14dBm to +20dBm LO Buffers/Splitters

with ±1dB Variation

_______________________________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS—MAX9987

(Typical Application Circuit, VCC= 4.75V to 5.25V, 50Ω environment, +4dBm < PIN< +10dBm, 700MHz < fIN< 1100MHz,
T

A

= -40°C to +85°C, unless otherwise noted. Typical specifications are for VCC= 5.0V, PIN= +7dBm, fIN= 900MHz, and

T

A

= +25°C, unless otherwise noted.) (Note 1)

PARAMETER

CONDITIONS

UNITS

Operating Frequency f

MHz

Low power setting, PIN = +4dBm
(see Table 1 for resistor values)

Nominal power setting,
+4dBm < P

IN

< +10dBm, 4.75V < VCC <

5.25V, -40°C < T

A

< +85°C

(R

1

, R2, R4, and R5 not installed)

17.3

Output Power (Main Drivers) P

OUTLO

High power setting, PIN = +10dBm
(see Table 1 for resistor values)

dBm

Output Power (PLL Driver)

3.7

dBm

Input VSWR VSWR

IN

Output VSWR

Output-Noise Power Density P

NOISE

V

CC

= 5.0V, ±100MHz offset

(R

1

, R2, R4, and R5 not installed)

dBm/Hz

OUT1 to OUT2 Isolation S23

V

CC

= 5.0V, nominal power setting

(R

1

, R2, R4, and R5 not installed)

45 dB

OUT2 to OUT1 Isolation S32

V

CC

= 5.0V, nominal power setting

(R

1

, R2, R4, and R5 not installed)

39 dB

OUT1 to RFIN Isolation S12

V

CC

= 5.0V, nominal power setting

(R

1

, R2, R4, and R5 not installed)

48 dB

OUT2 to RFIN Isolation S13

V

CC

= 5.0V, nominal power setting

(R

1

, R2, R4, and R5 not installed)

50 dB

SYMBOL

P

OUTPLL

VSWR

OUT

MIN TYP MAX

700 1100

14.3

±0.8

19.7

1.2:1

1.7:1

-152

MAX9987/MAX9988

+14dBm to +20dBm LO Buffers/Splitters
with ±1dB Variation

4 _______________________________________________________________________________________

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Operating Frequency f

MHz

Low power setting, PIN = +6dBm
(see Table 1 for resistor values)

Nominal power setting,
+6dBm < P

IN

< +12dBm, 4.75V < VCC <

5.25V, -40°C < T

A

< +85°C

(R

1

, R2, R4, and R5 not installed)

17.3

Output Power
(Main Drivers)

High power setting, PIN = +12dBm
(see Table 1 for resistor values)

dBm

Output Power
(PLL Driver)

3.6

dBm

Input VSWR
Output VSWR
Output-Noise Power Density

VCC = 5.0V, ±100MHz offset

dBm/Hz

OUT1 to OUT2 Isolation S23

V

CC

= 5.0V, nominal power setting

(R

1

, R2, R4, and R5 not installed)

33 dB

OUT2 to OUT1 Isolation S32

V

CC

= 5.0V, nominal power setting

(R

1

, R2, R4, and R5 not installed)

44 dB

OUT1 to RFIN Isolation S12

V

CC

= 5.0V, nominal power setting

(R

1

, R2, R4, and R5 not installed)

49 dB

OUT2 to RFIN Isolation S13

V

CC

= 5.0V, nominal power setting

(R

1

, 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
T

A

= -40°C to +85°C, unless otherwise noted. Typical specifications are for VCC= 5.0V, PIN= +9dBm, fIN= 1800MHz, and

T

A

= +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 derived

from the average of 30 units from a typical lot, and are tested under the conditions specified for the typical specifications.

1500 2200

14.2

P

OUTLO

P

OUTPLL

VSWR

VSWR

P

NOISE

OUT

IN

±0.8

19.5

1.5:1

1.4:1

-152