NSC LMX2604LQX Triple-band vco for gsm900/dcs1800/pcs1900 Datasheet

LMX2604
Triple-band VCO for GSM900/DCS1800/PCS1900
General Description
Features
The LMX2604 is a fully integrated VCO (Voltage-Controlled
Oscillator) IC designed for GSM900/DCS1800/PCS1900
triple-band application. The IC is ideal for use in the transmitter modulation loop by providing extremely small form
factor and low phase noise. The IC has two VCOs, one for
GSM and a second for DCS/PCS. The IC has two separate
buffer amplifiers to drive an external high power amplifier,
one for GSM900 band and the other one for DCS1800/
PCS1900 bands. The IC also has a differential buffer amplifier to drive a mixer for the offset PLL.
The resonant circuits of the VCOs are fully integrated in the
chip to ease the application of the IC. The high quality factor
of the embedded tank circuit achieves very low phase noise
characteristics at the VCO output. The only required external
components are a couple of supply bypass capacitors and
matching components.
A control pin for controlling the oscillation frequency is
shared by the two VCOs.
The LMX2604 IC is provided in a 20-pin 4x4 LLP (Leadless
Leadframe package).
n On-chip Triple-band RF VCOs
GSM: 880 MHz to 915 MHz
DCS: 1710 MHz to 1785 MHz
PCS: 1850 MHz to 1910 MHz
n On-chip tank circuit
n Low phase noise
— -167 dBc/Hz @ 20 MHz offset in GSM band
— -163 dBc/Hz @ 20 MHz offset in DCS band
— -162 dBc/Hz @ 20 MHz offset in PCS band
n High output power
— +6 dBm in GSM mode
— +6 dBm in DCS and PCS mode
n Low current consumption
— 18 mA in GSM mode
— 15 mA in DCS and PCS mode
n +2.6 V to +3.0 V supply voltage
n 0.25 µm RF CMOS process
n Small 20-pin 4x4 LLP package
Applications
n Transmit VCO for GSM, DCS, and PCS
n Closed loop modulation systems
Functional Block Diagram
20066101
FastLock™ is a trademark of National Semiconductor Corporation.
TRI-STATE ® is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation
DS200661
www.national.com
LMX2604 Triple-band VCO for GSM900/DCS1800/PCS1900
January 2004
LMX2604
Connection Diagram
20-Pin 4x4 LLP (TM) Package
20066102
Pin Descriptions
Pin Number
Name
I/O
1
CE
I
Description
2,4,15
GND (Note 1)
—
Ground pins
3
MIXout
O
Mixer output pin (RF output)
5
BSW
I
Band switch input pin. High=DCS/PCS, Low=GSM
11,19
VDD
—
Supply voltage pins
12
GSMout
O
RF output pin for VCO in GSM band
13
DCSPCSout
O
RF output pin for VCO in DCS and PCS band
16
CPin
I
Charge pump input pin
6,7,8,9,10,14,17,18,20
NC
—
Chip enable input pin. High=enable, Low=disable
No Connection, These pins must be left open
Note 1: The exposed die attach pad is grounded.
Ordering Information
Package
Part Number
Package Marking
Media Transport
NSC Drawing
20-Pin LLP
LMX2604LQ
LMX2604LQ
1000 Unit Tape and Reel
LQA20A
20-Pin LLP
LMX2604LQX
LMX2604LQ
4500 Unit Tape and Reel
LQA20A
www.national.com
2
LMX2604
Absolute Maximum Ratings (Notes 3, 4, 5)
Parameter
Symbol
Ratings
Unit
V
Supply Voltage
VDD
-0.3 to 3.6
Input Voltage
VIN
-0.3 to VDD+0.3
V
Input Current (Note 2)
IIN
10
mA
TSTG
-65 to 150
˚C
Storage Temperature Range
Note 2: Maximum input current is for a logic pin, not the power pins.
Recommended Operating Conditions
Parameter
Ambient Temperature
Supply Voltage (to GND)
Symbol
Condition
Min
Typical
Max
Unit
TA
VDD=3V
-30
25
85
˚C
2.6
2.8
3.0
V
VDD
Note 3: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The
guaranteed specifications apply only for the test conditions listed.
Note 4: This Device is a high performance RF integrated circuit with an ESD rating < 2 kV and is ESD sensitive. Handling and assembly of this device should only
be done at ESD-free workstations.
Note 5: Stresses in excess of the absolute maximum ratings can cause permanent or latent damage to the device. These are absolute stress ratings only.
Functional operation of the device is only implied at these or any other conditions in excess of those given in the operation sections of the data sheet. Exposure to
absolute maximum ratings for extended periods can adversely affect device reliability
Electrical Characteristics
AC Characteristics (VDD=2.8V, TA=25˚C; unless otherwise noted)
Symbol
f
KVCO
Pout
PMIXout
L(f)
L(f)
L(f)
Parameter
Frequency Range
Tuning Sensitivity
(Note 6)
Output Power
Output power of
MIXout pin
Phase Noise
(GSM Band)
Phase Noise
(DCS Band)
Phase Noise
(PCS Band)
Second Harmonic
Suppression
Remarks
Min
Max
Units
GSM Band
880
Typ
915
MHz
DCS Band
1710
1785
PCS Band
1850
1910
GSM Band
10
15
20
DCS Band
15
20
25
PCS Band
20
25
30
GSM Band
4
6
8
DCS & PCS Band
4
6
8
GSM Band
-5.5
-3.5
-1.5
DCS & PCS Band
-4.5
-2.5
-0.5
at 100 kHz offset
-120
at 400 kHz offset
-136
at 3 MHz offset (Note 7)
-152
at 20 MHz offset (Note 7)
-167
at 100 kHz offset
-112
at 400 kHz offset
-130
at 3 MHz offset (Note 7)
-146
at 20 MHz offset (Note 7)
-163
at 100 kHz offset
-110
at 400 kHz offset
-129
at 3 MHz offset (Note 7)
-145
at 20 MHz offset (Note 7)
-162
All Bands at RF output port.
-20
-128
-124
-124
-15
MHz
MHz/V
dBm
dBm
dBc/Hz
dBc/Hz
dBc/Hz
dBc
Note 6: Tuning Sensitivty is measured after coarse lock. Minimum and maximum limits are supported by characterization.
Note 7: Supported by characterization
3
www.national.com
LMX2604
Electrical Characteristics
(Continued)
DC Characteristics (VDD=2.8V, TA=25˚C; unless otherwise noted)
Symbol
Parameter
Max
Units
0.8VDD
VDD+0.3
V
Logical Input Low
Voltage
-0.3
0.2VDD
V
IIH
Logical Input High
Current
-2.5
2.5
µA
IIL
Logical Input Low
Current
-2.5
2.5
µA
VIH
Logical Input High
Voltage
VIL
Condition
Min
Typ
Input Capacitance
5
IDD,GSM
Supply Current
(Note 8)
18
21
mA
IDD,DCS/PCS
Supply Current
(Note 8)
15
18
mA
2.5
µA
Istd
Standby Current
Note 8: The current consumption in VCO and driver amplifier is all included
Note 9: For CE, BSW, and CPin pins
www.national.com
4
pF
LMX2604
Typical Performance Characteristics : Phase Noise
Typical phase noise characteristics in GSM band
20066161
Typical phase noise characteristics in DCS band
20066162
5
www.national.com
LMX2604
Typical Performance Characteristics : Phase Noise
(Continued)
Typical phase noise characteristics in PCS band
20066163
www.national.com
6
LMX2604
Typical Performance Characteristic : GSMout Impedance
GSMout
20066130
GSMout
Frequency (MHz)
Real (Ohms)
Imaginary (Ohms)
Absolute (Ohms)
800
126
-72
146
850
126
-74
146
900
126
-75
146
950
126
-77
147
1000
125
-80
149
7
www.national.com
LMX2604
Typical Performance Characteristic : MIXout Impedance, GSM
MIXout, GSM
20066131
MIXout, GSM
Frequency (MHz)
Real (Ohms)
Imaginary (Ohms)
Absolute (Ohms)
800
141
-256
292
850
133
-249
282
900
126
-243
274
950
120
-237
266
1000
115
-232
259
www.national.com
8
LMX2604
Typical Performance Characteristic : DCSPCSout Impedance
DCSPCSout
20066132
DCSPCSout
Frequency (MHz)
Real (Ohms)
Imaginary (Ohms)
Absolute (Ohms)
1600
80
-54
96
1650
78
-53
94
1700
77
-51
93
1750
76
-50
91
1800
73
-49
88
1850
71
-48
85
1900
68
-48
83
1950
64
-48
80
2000
57
-51
77
9
www.national.com
LMX2604
Typical Performance Characteristic : MIXout Impedance, DCS/PCS
MIXout, DCS/PCS
20066133
MIXout, DCSPCS
Frequency (MHz)
Real (Ohms)
Imaginary (Ohms)
Absolute (Ohms)
1600
66
-164
177
1650
65
-162
175
1700
64
-160
172
1750
66
-157
171
1800
64
-157
169
1850
63
-153
166
1900
62
-150
162
1950
61
-146
159
2000
59
-143
155
www.national.com
10
FREQUENCY SELECTION AND POWER DOWN
CONTROL
PRODUCT DESCRIPTION
The BSW pin selects the operating frequency band. The
table below shows the appropriate settings with the CE pin.
The LMX2604 IC has two VCOs, which are configured as an
LC resonant oscillator. The active components and tank
elements are all integrated on the IC. The oscillator core and
the tank circuit are designed to be immune to external noise
such as supply and load variation. The IC is easy-to-use and
occupies extremely small area in the board.
Two output amplifiers are also integrated to deliver high
output power of +6 dBm in GSM/DCS/PCS applications. The
amplifiers isolate the oscillator cores from the external load,
and drive the external 50 ohm load. The output driver is
designed to have low noise floor and to reduce pulling by
load variation. An additional amplifier to drive the mixer in the
transmit PLL is also provided. Only an attenuator composed
of a few passive elements is necessary to meet the power
level of the mixer input of the transmit PLL.
CE
BSW
Output
Low
Low
X
Low
High
X
High
Low
Low Band (GSM)
High
High
High Band (DCS/PCS)
In real implementation, the component values of the tank
circuit vary from the nominal value. The IC has built-in circuit
to track the variation and compensate that kind of the variation during normal operation. This self-correction algorithm
does not require any external control signal and elements.
The figure below shows an application circuit of the
LMX2604. The LMX2604 is developed for the use in a GSM
handset as part of the transmitter PLL. To complete the
offset PLL in the transmit path, several passive elements for
the external loop filter should be also provided. The charge
pump output port of the external transceiver IC is fed to the
CPin pin.
The locking process of the LMX2604 is composed of two
stages. First, the internal control circuitry of the LMX2604
controls the fast frequency acquisition behavior of the
LMX2604. After the frequency acquisition, the whole loop
enters in its normal operating mode.
The frequency of the oscillator is controlled by the CPin pin,
which is internally connected to the varactor. This control pin
is connected to the loop filter of the modulation loop in the
transmit path. Any additional noise on this tuning input is
directly translated into FM noise, which can degrade the
phase noise characteristics of the oscillator. Typically, the
loop filter of the PLL provides an appropriately low impedance source at its output and thus proper additional filtering
stage is often required to reduce the high frequency noise
and spurious signals.
Application Circuit of LMX2604
20066172
11
www.national.com
LMX2604
Functional Description
LMX2604
Functional Description
frequency such that the final tuning voltage on the CPin line
of the VCO is approximately Vdd/2. Benefits of this system is
the maximum required charge pump voltage is reduced as
large frequency ranges may be tuned with a small tuning
voltage. This makes the digitally tuned VCO different from
conventional analog VCOs.
(Continued)
FREQUENCY ACQUISITION
On the rising edge of CE the VCO goes through a frequency
acquisition mode which coarse locks the PLL to the approximate final frequency. This portion of the lock digitally sets the
Frequency Acquisition Timing Diagram
20066122
www.national.com
12
LMX2604
Physical Dimensions
inches (millimeters) unless otherwise noted
20066107
20-Pin LLP (Leadless Leadframe package) Package
Order Number LMX2604LQX for 4500 Unit Reel
Order Number LMX2604LQ for 1000 Unit Reel
NS Package Number LQA20
13
www.national.com
LMX2604 Triple-band VCO for GSM900/DCS1800/PCS1900
Notes
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
BANNED SUBSTANCE COMPLIANCE
National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products
Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification
(CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2.
National Semiconductor
Americas Customer
Support Center
Email: [email protected]
Tel: 1-800-272-9959
www.national.com
National Semiconductor
Europe Customer Support Center
Fax: +49 (0) 180-530 85 86
Email: [email protected]
Deutsch Tel: +49 (0) 69 9508 6208
English Tel: +44 (0) 870 24 0 2171
Français Tel: +33 (0) 1 41 91 8790
National Semiconductor
Asia Pacific Customer
Support Center
Email: [email protected]
National Semiconductor
Japan Customer Support Center
Fax: 81-3-5639-7507
Email: [email protected]
Tel: 81-3-5639-7560
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
Similar pages