SI4133-D-GM - Triple-VCO 1.72GHz RF Synthesizer | Silicon Labs
MPN: SI4133-D-GM ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.3339 | $3.33 |
| 10 | $3.3339 | $33.34 |
| 100 | $3.3339 | $333.39 |
| 500 | $3.3339 | $1,666.95 |
| 1,000 | $3.3339 | $3,333.90 |
SI4133-D-GM Overview
An RF frequency synthesizer is a phase-locked-loop timing and RF component that generates a programmable output from a stable reference. The Si4133 combines IF synthesis with dual-band RF synthesis, placing it in the RF synthesizer, PLL, clock-generation, and wireless-communications equipment hierarchy. Its integrated VCOs eliminate separate external VCO and varactor assemblies in suitable designs.
The device supports three synthesizer circuits, programmable power-down modes, low phase noise, and a 1 uA standby current. According to the manufacturer product information, it targets price-sensitive, low-power, high-performance personal wireless communications while reducing passive-component count and improving power efficiency. LCSC lists a starting price of $3.3339 as of 2026-10-22.
The listed operating supply range is 2.7 V to 3.6 V. The manufacturer describes low-noise IF and dual-band RF synthesis, while distributor data identifies the output capability as up to 1.72 GHz. The exposed pad supports heat transfer to the PCB, but loop-filter values, VCO tuning range details, phase-noise plots, and complete timing specifications must be taken from the manufacturer datasheet rather than inferred from distributor summaries.
Typical uses include wireless personal-communications equipment, IF/RF up-conversion systems, dual-band transmitters, low-power radio designs, and compact RF modules. System designers should preserve clean reference routing, provide compliant loop filtering, decouple the supply, and connect the exposed pad to the recommended thermal and ground-plane layout.
A design tradeoff is integration versus program flexibility: integrating three VCOs, dividers, filters, and detectors simplifies RF assembly, but the planner must still account for lock-time, spur, tuning-range, reference-noise, and thermal requirements for the intended band. Verify all band-specific constraints against the official datasheet.
This page consolidates manufacturer and distributor information, verified source links, application guidance, and replacement screening into an engineering-focused summary. Because the supplied data does not establish several detailed electrical limits or lifecycle classifications, those fields remain explicitly marked rather than guessed.
Drop-in alternatives for SI4133-D-GM — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with SI4133-D-GM (same form factor and footprint) — differing in Mounting Type, Package, Product Type, Number of Circuits, Integrated VCO Count.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SI4133-D-GMR
✅ Drop-In📋 Reference alternative (not in catalog)
SI4133-BT
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →SI4133-D-GM Specifications
| Product Type | IF and dual-band RF frequency synthesizer IC |
| Number of Circuits | 3 circuits |
| Maximum Input Frequency | 26 MHz |
| Minimum Input Frequency | 2 MHz |
| Maximum Output Frequency | 1.72 GHz |
| Supply Voltage Range | 2.7 V to 3.6 V |
| Integrated VCO Count | 3 VCOs |
| Integrated Blocks | 3 loop filters, reference divider, VCO dividers, and phase detectors |
| Standby Current | 1 uA |
| Power-Down Modes | Programmable |
| Operating Temperature Range | -40 C to +85 C |
| Package | QFN-28 with exposed pad |
| Pin Count | 28 pins |
| Mounting Type | Surface-mount |
| Manufacturer Category | Phase Locked Loops (PLL) |
| RoHS Status | unknown |
| REACH Status | unknown |
SI4133-D-GM qfn-28 with exposed pad Pin Configuration Guide
Pin configuration for SI4133-D-GM (qfn-28 with exposed pad package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for SI4133-D-GM.
Refer to the datasheet for full pin configuration.
Typical Applications
SI4133-D-GM is suitable for 6 applications: Wireless Personal Communications, Dual-Band RF Transmitter, IF and RF Up-Conversion, Low-Power Wireless Module, RF Test and Measurement, Industrial Radio Control.
Wireless Personal Communications
The SI4133-D-GM fits wireless personal-communications equipment because it performs IF and dual-band RF synthesis in one IC while integrating three VCOs, loop filters, dividers, and phase detectors. The 2.7 V to 3.6 V operating range suits 3.3 V-class systems, while programmable shutdown supports duty-cycled radios. Integration can reduce external VCO, varactor, and passive-component count. Designers must still validate each required output band, lock behavior, reference plan, and supply-noise margin against the official datasheet before layout release.
Recommended
Dual-Band RF Transmitter
The SI4133-D-GM is applicable to dual-band RF transmitters because the manufacturer identifies dual-band RF synthesis and three integrated VCO circuits. A transmitter can use the synthesizer for programmable local-oscillator generation while retaining the IF synthesis path, reducing the number of discrete frequency-generation blocks. The verified output capability reaches 1.72 GHz and reference input spans 2 MHz to 26 MHz. Exact channel plans require confirmation of VCO ranges, channel spacing, lock time, spur performance, and output-drive limits.
Recommended
IF and RF Up-Conversion
For IF-to-RF up-conversion, the SI4133-D-GM combines IF synthesis with RF synthesis and includes reference and VCO dividers plus phase detectors. This integration can simplify a compact RF signal chain by avoiding separate external VCO and varactor implementations. The device operates from a 2.7 V to 3.6 V supply and supports output operation up to 1.72 GHz according to distributor data. The RF layout must control reference spurs, loop-filter noise, supply coupling, and exposed-pad thermal return paths.
Recommended
Low-Power Wireless Module
The SI4133-D-GM supports low-power wireless-module designs through programmable power-down modes and a listed 1 uA standby current. Its integrated synthesis blocks reduce external components, helping conserve board area and assembly effort. The manufacturer targets personal wireless systems where low power and cost are important. Active operating current is not present in the supplied snippets, so battery-life calculations must use the complete datasheet operating profile and the module's actual lock-cycle duty cycle.
Recommended
RF Test and Measurement
The SI4133-D-GM can generate programmable IF and RF frequencies for compact test equipment when its specified tuning ranges meet the instrument requirement. Three integrated VCOs allow multi-range synthesis without three separate external VCO assemblies, while integrated filters and phase detectors support a compact implementation. Reference integrity becomes especially important because phase noise and spur behavior propagate into measurement accuracy. Confirm calibration paths, lock-time requirements, output power, and channel resolution before selecting it.
Recommended
Industrial Radio Control
The SI4133-D-GM is suitable for industrial radio-control systems requiring IF and RF synthesis from a common reference domain. Programmable shutdown can assist power management, and the -40 C to +85 C listed operating range covers many industrial environments. The integrated VCO architecture may reduce assembly complexity compared with discrete frequency-generation circuits. Engineers should verify RF regulatory constraints, temperature-specific phase-noise behavior, grounding, reference isolation, and all absolute-maximum limits before industrial deployment.
Recommended
Recommended Products Summary
Engineering reference data for SI4133-D-GM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SI4133-D-GMR | SI4133-BT |
|---|---|---|---|
| Package | QFN-28 with exposed pad | QFN-28 | TSSOP-24 / QFN-28 variants listed; exact SI4133-BT package requires verification |
| Brand | Silicon Labs | Silicon Labs | Silicon Labs |
| Product Type | IF and dual-band RF synthesizer | PLL frequency synthesizer | Si4133-family PLL/RF synthesizer |
Key Differentiators
- Integrated triple-VCO RF synthesis (vs SI4133-D-GMR)
- IF and dual-band synthesis in one device (vs SI4133-BT)
- Reduced external RF component count (vs Discrete VCO and varactor implementation)
- Power-conscious wireless operation (vs Continuously powered discrete synthesizer)
Design Notes
Route the reference clock as a short, controlled-impedance trace and keep it away from synthesizer outputs and switching-node return currents. Because reference phase noise can multiply through the PLL and appear as close-in phase noise or spurs, use the manufacturer's recommended grounding and decoupling topology. Place supply bypass capacitance at the relevant pins and provide a continuous return path beneath the exposed-pad region.
The QFN exposed pad is the primary thermal and electrical land feature. Follow the official package drawing for pad dimensions, solder mask, paste, via count, and net assignment. Thermal performance depends on the PCB stack-up and copper area, so do not infer junction temperature from package size alone. Validate hot-lock operation across ambient temperature and the highest intended RF activity.
Keep RF output routing compact and match it to the intended 50-ohm interface using the manufacturer reference layout where available. Avoid coupling output and reference traces, maintain continuous ground references, and isolate control buses from sensitive RF paths. Review loop-filter component placement carefully because poor grounding or trace inductance can degrade phase noise and spur behavior even when the nominal component values are correct.
Do not treat package similarity as proof of interchangeability. Confirm every pin, supply limit, exposed-pad connection, programming register, frequency boundary, and absolute maximum before replacing SI4133-D-GM. In particular, SI4133-BT includes package variants that do not necessarily match this QFN-28 footprint. Also avoid extending the verified 1.72 GHz listing into unsupported VCO ranges without consulting the official tuning tables.
Compliance Information
The supplied distributor page mentions RoHS but provides no explicit compliant or non-compliant declaration. AEC-Q100 is treated as not applicable because no automotive qualification claim is supplied; this field should not be interpreted as an automotive approval.
