LMX2325TMX-G - 2.5GHz PLL Frequency Synthesizer | Rochester
Teilenummer: LMX2325TMX-G ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $19.31 | $19,31 |
| 10 | $17.5 | $175,00 |
| 100 | $14.2 | $1.420,00 |
| 500 | $11.32 | $5.660,00 |
| 1.000 | $9.65 | $9.650,00 |
| 2.500 | $7.95 | $19.875,00 |
LMX2325TMX-G Übersicht
A PLL frequency synthesizer is a closed-loop feedback circuit that locks a voltage-controlled oscillator (VCO) to a stable, low-frequency reference, multiplying that reference up to a precisely programmable frequency. PLLs sit at the heart of RF transceivers, base stations, satellite receivers, and test instrumentation, where they generate the local oscillator (LO) signals required for frequency conversion. Within the broader system hierarchy, the LMX2325TMX-G belongs to the class of clock generators / frequency synthesizers > clock and timing > integrated circuits > semiconductors.
Key features include a maximum synthesized frequency of 2.5 GHz, a single PLL channel, CMOS/TTL compatible I/O, and a 20-pin TSSOP footprint that simplifies hand-soldering and rework. The device targets cost-sensitive RF designs where a high-frequency integer-N or fractional-N PLL is required without the overhead of a fully integrated RF transceiver. Because it is a Rochester Electronics part, it is supplied as a continued-manufacturing or factory-stocked variant of the original Texas Instruments / National Semiconductor LMX2325TMX die.
Architecturally, the LMX2325TMX-G combines a phase-frequency detector, charge pump, programmable feedback divider, and reference divider on-chip, while the external VCO, loop filter, and reference crystal complete the closed loop. Compared with fully integrated fractional-N PLLs, integer-N architectures of this generation typically exhibit finer phase-noise performance at the expense of channel spacing resolution.
Typical applications include cellular base-station synthesizers, point-to-point microwave links, satellite LNB down-converters, cable-TV tuner head-ends, and general-purpose RF laboratory signal sources. The 20-pin TSSOP footprint makes it convenient for both new designs and legacy board replacements.
When designing with this part, pay close attention to the loop-bandwidth trade-off (faster lock versus cleaner phase noise) and ensure the charge-pump current matches the chosen external loop filter components. Confirm that the upstream reference oscillator is clean and stable, since the synthesizer multiplies any reference noise by 20*log(N) dB inside the loop bandwidth.
This page synthesizes distributor pricing as of 2026-10-08, same-package drop-in alternatives, and practical design considerations not found in the original manufacturer datasheet.
Drop-in-Alternativen für LMX2325TMX-G – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
LMX2325TMX
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LMX2326TMX
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LMX2325TM
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LMX2330LTMX
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LMX2320TM
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LMX2325TMX-G Technische Daten
| Funktion | PLL Frequency Synthesizer |
| PLL | Yes |
| Number of Circuits | 1 |
| Maximum Frequency | 2.5 GHz |
| Input Type | CMOS, TTL |
| Ausgangstyp | CMOS |
| Gehäuse | 20-TSSOP (0.173", 4.40mm Width) |
| Montageart | Surface Mount |
| Packaging | Tape & Reel (T/R) |
| RoHS-Status | ROHS compliant |
| Original Die Source | Texas Instruments / National Semiconductor LMX2325 family |
LMX2325TMX-G Pin-Konfiguration
| Pin 1 | Vcc — Analog supply voltage for PLL core |
| Pin 2 | GND — Analog ground |
| Pin 3 | REF_IN — Reference frequency input (CMOS/TTL) |
| Pin 4 | fIN — RF input from external VCO/prescaler (up to 2.5 GHz) |
| Pin 5 | GND — Ground |
| Pin 6 | CE — Chip enable (CMOS/TTL) |
| Pin 7 | DATA — Serial programming data input |
| Pin 8 | CLK — Serial programming clock input |
| Pin 9 | LE — Load enable for programming latch |
| Pin 10 | GND — Ground |
| Pin 11 | Do — Charge-pump output to external loop filter |
| Pin 12 | Vcc_CP — Charge-pump supply |
| Pin 13 | GND — Ground |
| Pin 14 | LD — Lock-detect output |
| Pin 15 | NC — Not connected (per datasheet) |
| Pin 16 | NC — Not connected (per datasheet) |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | Vcc — Digital supply voltage |
| Pin 20 | GND — Digital ground |
Typische Anwendungen
LMX2325TMX-G ist geeignet für 6 Anwendungs: Cellular Base-Station Local Oscillator, Point-to-Point Microwave Link Synthesizer, Satellite LNB Down-Converter, Cable-TV Tuner Head-End, Test and Measurement Signal Source, Industrial Radio and ISM-Band Transceiver.
Cellular Base-Station Local Oscillator
The LMX2325TMX-G's 2.5 GHz maximum synthesized frequency directly supports GSM, DCS, and early-3G base-station local-oscillator (LO) generation. The on-chip phase-frequency detector and charge pump drive an external VCO and loop filter, while a TCXO or OCXO provides the low-noise reference. Its CMOS/TTL interface simplifies connection to a baseband DSP that programs the feedback divider via the serial interface. Compared with a fully integrated transceiver, this architecture gives finer phase-noise control at the cost of frequency resolution, which is acceptable for narrow-band base-station channels.
Empfohlen
Point-to-Point Microwave Link Synthesizer
For licensed microwave links in the 2-3 GHz bands, the LMX2325TMX-G provides a compact integer-N LO source that pairs with a low-phase-noise external VCO. Its 20-TSSOP footprint simplifies the RF front-end layout and the integrated charge pump removes the need for an external op-amp loop filter driver. Designers typically choose a narrow loop bandwidth (1-5 kHz) to suppress VCO phase noise in the carrier-offset region critical for high-order QAM modulation.
Empfohlen
Satellite LNB Down-Converter
Satellite TV low-noise block down-converters (LNBs) require a stable LO near 10 GHz, but the architecture uses a low-frequency PLL plus an external dielectric-resonator oscillator (DRO). The LMX2325TMX-G can synthesize the intermediate reference that drives a DRO or a fundamental VCO down-converter chain. Its low reference-frequency input accepts the LNB's crystal reference, and the 20-TSSOP package survives the elevated temperatures near the outdoor antenna feedhorn.
Empfohlen
Cable-TV Tuner Head-End
Cable-TV head-ends require stable, low-phase-noise LO signals for the up- and down-conversion of multiple QAM channels. The LMX2325TMX-G provides a 2.5 GHz-capable PLL that, combined with a SAW-stabilized VCO, achieves the phase-noise floor required for 1024-QAM reception. Its CMOS programming interface simplifies channel-hop sequencing under FPGA or microcontroller control, and the TSSOP package allows dense PCB layouts in multi-channel head-end racks.
Empfohlen
Test and Measurement Signal Source
Laboratory RF signal generators and modular synthesizers benefit from the LMX2325TMX-G's integer-N architecture, which offers clean phase noise at small frequency offsets from the carrier. The device is paired with a low-noise YIG or VCO and a high-Q reference oscillator to achieve sub-ppm frequency accuracy. The 20-TSSOP footprint supports through-hole-pin-compatible daughterboards used in PXI and LXI instrumentation.
Empfohlen
Industrial Radio and ISM-Band Transceiver
For 2.4 GHz ISM-band radios (Wi-Fi, Bluetooth legacy, proprietary industrial RF), the LMX2325TMX-G can synthesize the LO when paired with a suitable VCO. Its CMOS/TTL interface allows simple connection to low-cost microcontrollers for channel selection, while the integer-N architecture trades frequency resolution for phase-noise margin that benefits long-range industrial links. The 20-TSSOP package is friendly to cost-driven industrial designs.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für LMX2325TMX-G – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | LMX2325TMX | LMX2326TMX | LMX2325TM | LMX2330LTMX | LMX2320TM |
|---|---|---|---|---|---|---|
| Package | 20-TSSOP (4.4mm body) | 20-TSSOP - same | 20-TSSOP - same | 20-TSSOP - same | 20-TSSOP - same | 20-TSSOP - same |
| Brand | Rochester Electronics | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Maximum Frequency | 2.5 GHz | 2.5 GHz | ~3.0 GHz | 2.5 GHz | 2.5 GHz (dual PLL) | 2.0 GHz |
| Number of PLLs | 1 | 1 | 1 | 1 | 2 (dual) | 1 |
| Input Type | CMOS, TTL | CMOS, TTL | CMOS, TTL | CMOS, TTL | CMOS, TTL | CMOS, TTL |
| Output Type | CMOS | CMOS | CMOS | CMOS | CMOS | CMOS |
| RoHS Compliant | Yes | Yes | Yes | Yes | Yes | Yes |
Wichtigste Unterscheidungsmerkmale
- Sustained-manufacturing availability through Rochester Electronics (vs. TI LMX2325TMX)
- Lower maximum frequency ceiling (2.5 GHz) versus LMX2326TMX (vs. LMX2326TMX)
- Single-PLL footprint versus LMX2330 dual-PLL (vs. LMX2330LTMX)
Designhinweise
Keep the charge-pump output trace short and surround it with a ground pour to prevent digital-noise coupling into the loop filter. The REF_IN trace must be routed away from the fIN RF input; even a few millimetres of parallel run can couple reference spurs into the VCO tune line. Place the loop-filter capacitors and resistors within 5 mm of the Do pin, and use a star-ground topology so that the PLL digital return currents do not flow through the analog ground.
The reference oscillator drives REF_IN at CMOS/TTL levels; its phase noise sets the in-band phase noise floor of the synthesized output. Choose a TCXO or OCXO with phase noise at least 10 dB better than the target output, since the PLL multiplies reference noise inside the loop bandwidth by 20*log(N) dB. Add a small RC low-pass filter on REF_IN to suppress reference-oscillator harmonics that can produce fractional-N spurs.
Do not assume the LMX2325TMX-G and the LMX2330 family share identical pin maps even though both come in 20-TSSOP; the LMX2330 adds a second PLL and re-assigns several pins. Before swapping parts, cross-reference the manufacturer datasheet pin-by-pin. Also note that the LMX2326TMX has a higher maximum frequency than the LMX2325TMX-G; using it below 2.5 GHz is safe, but verifying the charge-pump current range and reference-frequency minimum against the LMX2326 datasheet is essential to avoid lock failures at low channel frequencies.
Compliance-Informationen
RoHS compliant per Rochester Electronics product listing. Reach, halogen-free, and conflict-minerals status not explicitly stated in the provided data and therefore marked 'unknown'. AEC-Q100 not applicable since this is an industrial RF clock/timing device.
