Datasheet RF9908, RF9908PCBA Datasheet (RF Micro Devices)

RF9908

6

Typical Applications

• CDMA/FM Cellular Systems

• Supports Dual-Mode AMPS/CDMA

• Supports Dual-Mode TACS/CDMA

Product Description

The RF9908 is a complete upconverter designed for
CDMA/FM cellular applications. The IC contains a dou­ble-balanced mixer stage and an output buffer amplifier
stage. This device may also be used to directly BPSK
modulate a carrier. The mixer is a Gilbert cell with emitter
degeneration resistors to provide high IP

stage is a class-B, push-pull configuration to reduce the
overall current and still provide a good 50Ω outputmatch.
The unit operates at 3.6V and does not require any exter­nal matching components other than coupling capacitors.
This circuit is designed as part of the RFMD CDMA Chip
Set, consisting of a Transmit IF AGC Amp, this Transmit
Upconverter, a Receive LNA/Mixer, and a Receive IF
AGC Amp.

. The output

3

CDMA/FM UPCONVERTER/BPSK MODULATOR

• Commercial and Consumer Systems

• 3-Cell Battery-Operated Systems

-A-

0.008

0.004

0.018

0.014

0.196

0.189

0.050

8° MAX

0° MIN

0.034

0.016

0.157

0.150

0.244

0.229

Dimensions in mm

0.009

0.007

NOTES:

1. Shaded lead is Pin 1.

2. All dimensions are excluding

3. Lead coplanarity -

0.068

0.053

mold flash.

0.005 with respect to datum "A".

6

MIXERS

Optimum Technology Matching® Applied

Si BJT GaAs MESFETGaAs HBT
Si Bi-CMOS

IF+

IF-

GND

LO+

ü

SiGe HBT

1

2

3

4

Si CMOS

8

RF OUT

7

VCC

6

GND

5

LO-

Functional Block Diagram

Package Style: SOIC-8

Features

• Supports Dual Mode Operation

• +8dBm Input/Output Intercept Point

• Single 3.6V Power Supply

• Internally Matched Inputs and Outputs

• Buffered Output

• Double-Balanced Mixer

Ordering Information

RF9908 CDMA/FM Upconverter/BPSK Modulator
RF9908 PCBA Fully Assembled EvaluationBoard

RF Micro Devices, Inc.
7628 Thorndike Road
Greensboro,NC 27409, USA

Tel [phone]

Fax [phone]

http://www.rfmd.com

Rev A2 010720

6-57

RF9908

Absolute Maximum Ratings

Parameter Rating Unit

Supply Voltage -0.5 to 7.0 V
Input RF Power +6 dBm

Operating Ambient Temperature -40 to +85 °C
Storage Temperature -40 to +150 °C

DC

Caution! ESD sensitive device.

RF Micro Devices believes thefurnished information is correct and accurate
at the time of this printing. However, RF Micro Devices reserves the right to
make changes to its products without notice. RF Micro Devices does not
assume responsibility for the use of the described product(s).

6

Parameter

Min. Typ. Max.

Overall

RF Output Frequency Range 500 to 1500 MHz
Conversion Gain 0 dB Over temperature and frequency
Noise Figure 14 dB
Output IP3 +8 dBm
Output ACP -54 dB Referenced to a 1.23MHz in-band power.

Output ALT -75 dB Referenced to a 1.23MHz in-band power.
Output VSWR 1.5:1 50Ω

Spurious Product Rejection 30 dBc Referenced to RF output

Specification

Unit Condition

T=25°C, VCC=3.6V, RF=840MHz,
LO=970MHz, IF=130MHz

(±885kHz offset)
(±1.98MHz offset)

IF Input

IF Frequency DC to 200 MHz

MIXERS

Differential Input Impedance 265 Ω
IF to RF Output Isolation 30 dB
IF to LO Isolation 30 dB

LO Input

LO Frequency Range 300 to 1700 MHz
LO Level -6to 0 dBm
LO to RF Output Leakage -30 -20 dBm
RF to LO Isolation 30 dB
LO Input VSWR 2:1 50Ω

Power Supply

Voltage 3.6±5% V
Current Consumption 18 mA

6-58

Rev A2 010720

RF9908

Pin Function Description Interface Schematic

1IF+

Balanced IF Input Pin. This pin is internally DC biased and should be
DC blocked if connected to a device with a DC level present. For single­ended input operation, one pin is used as an input and the other IF
input is AC coupled to ground. The balanced, as well as single-ended,
input impedance is 265Ω.

BIAS

IF-IF+

2IF­3GND

4LO+

5LO­6GND
7VCC

8RFOUT

Same as pin 1, except complementary input. See pin 1.
Ground connection. Keep traces physically short and connect immedi-

ately to ground plane for best performance.
Balanced LO Input Pin. This pin is internally DC biased and should be

DC blocked if connected to a device with a DC level present. For single­ended input operation, one pin is used as an input and the other LO
input is AC coupled to ground. The ba lanced, as well single-ended,
input impedance is 50Ω.

Same as pin 4, except complementary input. See pin 4.
Same as pin 3.
Supply Voltage pin. External bypassing is required. External RF, LO,

and IF bypassing is required. The trace length between the pin a n d the
bypass capacitors should be minimized. Th e ground sideofthe bypass
capacitors should connect immediately to ground plane.

RF Output Pin. This pinis internally DCblocked. The output impedance
is 50Ω.

LO-LO+

BIAS

6

MIXERS

RF OUT

Rev A2 010720

LO+

IF-

Application Schemati c

1nF

1

1nF

2

3

100 pF

4

8

7

6

5

100 pF

100 pF

V

RF OUTIF+

CC

100 nF

6-59

6

RF9908

Evaluation Board Schema t ic

(Download Bill of Materials from www.rfmd.com.)

P1

P1-1

NC

C1

T1

2.2 nF

IF IN

J1

C3
8pF

1:4

C2

2.2 nF

C4
10 nF

Evaluation Board Layout

Board Size 1.4” x 1.4”

MIXERS

Board Thickness 0.031”, Board Material FR-4

1

VCC

2

GND

3

1

2

3

4

9908400 Rev-

8

7

6

5

50Ω Microstrip

C6
47 pFC7100 nF

50ΩMicrostrip

C5

10 nF

RF OUT

J3

P1-1

LO-

6-60

Rev A2 010720