STMicroelectronics BALF-SPI2-01D3

Overview

BALF-SPI2-01D3 from STMicroelectronics is an ultra-miniature flip-chip balun filter integrating matching network and harmonic suppression, specifically conjugate-matched to the ST S2-LP RF transceiver for 860–930 MHz operation. It delivers 2.0 dB typical RX insertion loss, <1.6 dB amplitude imbalance, <9° phase imbalance, 50 Ω antenna port impedance, and 45 dB attenuation at 2fo - enabling compact sub-GHz IoT node front-ends.

For engineers reviewing the BALF-SPI2-01D3 datasheet, BALF-SPI2-01D3 pinout, BALF-SPI2-01D3 application, or BALF-SPI2-01D3 equivalent, key selection criteria include its 6-bump flip-chip footprint (2.10 × 1.55 mm), 620 µm max profile after reflow, ECOPACK®2 compliance, and verified integration with ST S2-LP evaluation boards.

Technical Context

This device implements a monolithic IPD (Integrated Passive Device) structure on non-conductive glass substrate, enabling precise impedance transformation between the differential RX port of the S2-LP and single-ended antenna path while simultaneously filtering harmonics up to 7fo. Its architecture integrates both balun functionality and bandpass filtering in one passive component.

The 6-bump flip-chip configuration places TX, RXP, RXN, ANT, and two GND terminals in fixed spatial layout optimized for minimal parasitic coupling. Matching is fixed and not tunable - designed exclusively for nominal 50 Ω antenna interface and S2-LP's differential 100 Ω RX input / 50 Ω TX output.

Key Specifications

Pinout & Package

Package: Flip-Chip 6 bumps (2.10 × 1.55 × 0.63 mm), ECOPACK®2-compliant, glass substrate IPD technology.

Key Features

Applications

Availability

BALF-SPI2-01D3 is available at Aetrix Electronics and suitable for smart utility meters, wireless sensor nodes, and asset trackers requiring stable component supply, high-volume tape-and-reel delivery, and long-term lifecycle assurance.

Supply support for BALF-SPI2-01D3 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader delivering intelligent power, sensing, connectivity, and microcontroller solutions for automotive, industrial, and consumer markets.

BALF-SPI2-01D3 belongs to ST's IPD balun filter product line - engineered to replace discrete matching networks in sub-GHz RF designs, targeting space-constrained IoT endpoints with strict regulatory compliance needs.

FAQ

What is the recommended PCB land pattern for BALF-SPI2-01D3?

The datasheet specifies a 220 µm copper pad diameter with 320 µm solder mask opening and 220 µm stencil aperture for 3-mil stencils. Clearance of 250 µm around pads is required for optimal sensitivity. A 1000 µm trace length between S2-LP QFN center and balun IPD center is mandatory to maintain impedance integrity.

Can BALF-SPI2-01D3 be used with RFICs other than ST S2-LP?

No - its impedance matching is fixed and optimized exclusively for the S2-LP's differential RX (100 Ω) and single-ended TX (50 Ω) ports. Using it with other transceivers results in >10 dB return loss degradation and harmonic filter misalignment, violating spectral masks.

What reflow profile should be used for this flip-chip device?

ST specifies a peak temperature of 240–245 °C for 60 seconds (max 90 s), ramp-up rate ≤3 °C/s, and cooling rate ≤6 °C/s. Air convection must be minimized to prevent component shift. The 0.9 °C/s preheat slope ensures uniform thermal distribution across the glass substrate.

Is external ESD protection needed despite the 2000 V HBM rating?

No - the 2000 V HBM rating is sufficient for standard SMT handling and field operation in Class 1B environments. ST validates this rating per JESD22-A114-C with all I/O tested individually while others are grounded, making external TVS diodes unnecessary in typical IoT deployments.