Document
LMX2604 Triple-band VCO for GSM900/DCS1800/PCS1900
January 2004
LMX2604 Triple-band VCO for GSM900/DCS1800/PCS1900
General Description
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).
Features
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
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LMX2604
Connection Diagram
20-Pin 4x4 LLP (TM) Package
20066102
Pin Descriptions
Pin Number 1 2,4,15 3 5 11,19 12 13 16 6,7,8,9,10,14,17,18,20
Note 1: The exposed die attach pad is grounded.
Name CE GND (Note 1) MIXout BSW VDD GSMout DCSPCSout CPin NC
I/O I — O I — O O I —
Description Chip enable input pin. High=enable, Low=disable Ground pins Mixer output pin (RF output) Band switch input pin. High=DCS/PCS, Low=GSM Supply voltage pins RF output pin for VCO in GSM band RF output pin for VCO in DCS and PCS band Charge pump input pin No Connection, These pins must be left open
Ordering Information
Package 20-Pin LLP 20-Pin LLP Part Number LMX2604LQ LMX2604LQX Package Marking LMX2604LQ LMX2604LQ Media Transport 1000 Unit Tape and Reel 4500 Unit Tape and Reel NSC Drawing LQA20A LQA20A
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LMX2604
Absolute Maximum Ratings (Notes 3, 4, 5)
Parameter Supply Voltage Input Voltage Input Current (Note 2) Storage Temperature Range
Note 2: Maximum input current is for a logic pin, not the power pins.
Symbol VDD VIN IIN TSTG
Ratings -0.3 to 3.6 -0.3 to VDD+0.3 10 -65 to 150
Unit V V mA ˚C
Recommended Operating Conditions
Parameter Ambient Temperature Supply Voltage (to GND) Symbol TA VDD Condition VDD=3V Min -30 2.6 Typical 25 2.8 Max 85 3.0 Unit ˚C V
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 Parameter Frequency Range Remarks GSM Band DCS Band PCS Band KVCO Tuning Sensitivity (Note 6) Output Power Output power of MIXout pin Phase Noise (GSM Band) GSM Band DCS Band PCS Band GSM Band DCS & PCS Band GSM Band DCS & PCS Band at 100 kHz offset L(f) at 400 kHz offset at 3 MHz offset (Note 7) at 20 MHz offset (Note 7) at 100 kHz offset L(f) Phase Noise (DCS Band) at 400 kHz offset at 3 MHz offset (Note 7) at 20 MHz offset (Note 7) at 100 kHz offset L(f) Phase Noise (PCS Band) Second Harmonic Suppression at 400 kHz offset at 3 MHz offset (Note 7) at 20 MHz offset (Note 7) All Bands at .