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LMX2370 Dataheets PDF



Part Number LMX2370
Manufacturers National Semiconductor
Logo National Semiconductor
Description Dual Frequency Synthesizer
Datasheet LMX2370 DatasheetLMX2370 Datasheet (PDF)

LMX2370/LMX2371/LMX2372 PLLatinum Dual Frequency Synthesizer for RF Personal Communications PRELIMINARY March 1999 LMX2370/LMX2371/LMX2372 PLLatinum™ Dual Frequency Synthesizer for RF Personal Communications LMX2370 LMX2371 LMX2372 2.5 GHz/1.2 GHz 2.0 GHz/1.2 GHz 1.2 GHz/1.2 GHz The LMX237X are available in a 24-pad chip scale (CSP) or a 20-pin TSSOP surface mount plastic package. Features n n n n n 2.7V–5.5V operation Ultra low current consumption Low phase detector noise floor Low voltage M.

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LMX2370/LMX2371/LMX2372 PLLatinum Dual Frequency Synthesizer for RF Personal Communications PRELIMINARY March 1999 LMX2370/LMX2371/LMX2372 PLLatinum™ Dual Frequency Synthesizer for RF Personal Communications LMX2370 LMX2371 LMX2372 2.5 GHz/1.2 GHz 2.0 GHz/1.2 GHz 1.2 GHz/1.2 GHz The LMX237X are available in a 24-pad chip scale (CSP) or a 20-pin TSSOP surface mount plastic package. Features n n n n n 2.7V–5.5V operation Ultra low current consumption Low phase detector noise floor Low voltage MICROWIRE™ interface (1.8V up to VCC) Low prescaler values 32/33 @ fIN ≤ 2.5 GHz 16/17 @ fIN ≤ 1.2 GHz 8/9 @ fIN ≤ 550 MHz Selectable charge pump current levels Selectable FastLock™ mode Enhanced ESD protection Small 24 pad chip scale package (3.5 x 4.5 x 1.0 mm) General Description The LMX237X family of monolithic, integrated dual frequency synthesizers, including prescalers, is designed to be used as a first and second local oscillator for dual mode or dual conversion transceivers. It is fabricated using National’s 0.5u ABiCV silicon BiCMOS process. The LMX237X contains two dual modulus prescalers. A 32/33 or a 16/17 prescaler can be selected for the 2.5 GHz and 2.0 GHz RF synthesizers with the 16/17 prescaler rated for input frequencies below 1.2 GHz. A 16/17 or an 8/9 prescaler can be selected for the 1.2 GHz RF synthesizers with the 8/9 prescaler rated for input frequencies below 550 MHz. Using a digital phase locked loop technique, the LMX237X can generate very stable, low noise control signals for UHF and VHF voltage controlled oscillators (VCO’s). Serial data is transferred into the LMX237X via a 1.8V three wire interface (Data, Enable, Clock) compatible with low voltage baseband processors. Supply voltage can range from 2.7V to 5.5V. The LMX237X family features very low current consumption typically: LMX2370 - 6.0 mA @ 3V, LMX2371 - 5.0 mA @ 3V, LMX2372 - 4.0 mA @ 3V. n n n n Applications n n n n Portable wireless communications (PCS/PCN, cordless) Dual mode cellular telephone systems Spread spectrum communication systems (CDMA) Cable TV tuners (CATV) Functional Block Diagram DS101026-1 FastLock™, PLLatinum™ and MICROWIRE™ are trademarks of National Semiconductor Corporation. TRI-STATE ® is a registered trademark of National Semiconductor Corporation. © 1999 National Semiconductor Corporation DS101026 www.national.com Connection Diagrams TSSOP 20-Pin Package CSP 24-Pin Package DS101026-2 Top View Order Number LMX2370TM, LMX2370TMX, LMX2371TM, LMX2371TMX, LMX2372TM or LMX2372TMX See NS Package Number MTC20 DS101026-3 Top View Order Number LMX2370SLBX, LMX2371SLBX or LMX2372SLBX See NS Package Number SLB24A Pin Descriptions Pin No. 24-Pin CSP 24 20-Pin TSSOP 1 Pin Name VCC1 I/O — Description Power supply voltage input for RF analog and RF digital circuits. Input may range from 2.7V to 5.5V. VCC1 must equal VCC2. Bypass capacitors should be placed as close as possible to this pin and be connected directly to the ground plane. Power supply for Main charge pump. Must be ≥ VCC. Internal Main charge pump output. For connection to a loop filter for driving the input of an external VCO. Ground for Main digital circuitry. Main prescaler input. Small signal input from the VCO. Main prescaler complementary input. For single ended operation, a bypass capacitor should be placed as close as possible to this pin and be connected directly to the ground plane. Ground for Main analog circuitry. Oscillator input. The input has a VCC/2 input threshold and can be driven from an external CMOS or TTL logic gate. Ground for Aux digital, MICROWIRE, FoLD, and oscillator circuits. Multiplexed output of the Main/Aux programmable or reference dividers, Main/Auxiliary lock detect signals and Fastlock mode. CMOS output (see Programmable Modes in the Datasheet). High impedance CMOS Clock input. Data for the various counters is clocked in on the rising edge, into the 22-bit shift register. Binary serial data input. Data entered MSB first. The last two bits are the control bits. High impedance CMOS input. Load enable. High impedance CMOS input. When LE goes HIGH, data stored in the shift registers is loaded into one of the 4 appropriate latches (control bit dependent). 2 3 4 5 6 2 3 4 5 6 Vp1 CPo1 GND fIN1 fIN1b — O — I I 7 8 10 11 7 8 9 10 GND OSCin GND Fo/LD — I — O 12 14 15 11 12 13 Clock Data LE I I I www.national.com 2 Pin Descriptions Pin No. 24-Pin CSP 16 20-Pin TSSOP 14 (Continued) Pin Name Vµc I/O — Description Power supply for MICROWIRE circuitry. Must be ≤ VCC. Typically connected to same supply level as µprocessor or baseband controller to enable programming at low voltages. Ground for Aux analog circuitry. Auxiliary prescaler input. Small signal input from the VCO. Ground for Aux digital, MICROWIRE, FoLD, and oscillator. Aux internal charge pump output. For connection to a loop filter for driving the input of an external VCO. Power supply for Aux charge pump. Must be ≥ VCC. Power supply voltage in.


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