Skyworks Solutions Inc. SKY12348-350LF

Overview

SKY12348-350LF from Skyworks Solutions is a GaAs pHEMT four-bit digital RF attenuator with 1 dB LSB, operating from 0.1 to 3.0 GHz, delivering 15 dB attenuation range, <1.4 dB typical insertion loss at 2.1 GHz, and +45 dBm IIP3. It serves as a precision signal-level control device in cellular infrastructure RF front-ends.

For engineers reviewing the SKY12348-350LF datasheet, SKY12348-350LF pinout, SKY12348-350LF application, or SKY12348-350LF equivalent, key selection criteria include broadband attenuation accuracy across 0.1–3.0 GHz, low DC power consumption (75 µA supply current), QFN-16 package compatibility, and high linearity for LTE/WiMAX base station transceivers.

Technical Context

The SKY12348-350LF implements a four-bit parallel-controlled GaAs pHEMT switch matrix with discrete 1/2/4/8 dB attenuation bits, enabling 16 linearly spaced states up to 15 dB. Control logic uses TTL-compatible DC voltage levels (0–0.8 V low, 3.3–VDD high) applied to V1–V4 pins.

RF signal path operates bidirectionally between RF1 and RF2 pins with matched 50 Ω impedance; four RFGND pins (4–5–6–8) require external AC-coupling capacitors to set low-frequency cutoff. The device achieves <±0.5 dB attenuation error at 2.1 GHz across all 16 states and maintains >15 dB input return loss over full bandwidth.

Key Specifications

Pinout & Package

SKY12348-350LF is housed in a 3 × 3 mm, 16-pin Quad Flat No-Lead (QFN) package with exposed thermal pad (MSL1, 260 °C reflow compatible). Pin 1 is marked by dot indicator; top-side markings include "Skyworks", part number, lot code, and date code (YYWW).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital RF attenuator applications.

Compared with QM11024 and HMC624LP4E, the SKY12348-350LF uniquely supports 5 V operation with TTL-compatible control, fits in compact 3×3 mm QFN, and delivers best-in-class IIP3 (+45 dBm) for high-linearity infrastructure use - making it optimal for LTE/WiMAX macro and small-cell designs requiring low-power, wideband precision attenuation.

Availability

SKY12348-350LF is available at Aetrix Electronics and suitable for cellular infrastructure, WiMAX radio modules, and active antenna calibration requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant manufacturing.

Supply support for SKY12348-350LF 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

Skyworks Solutions is a global leader in high-performance analog semiconductors for wireless communications, delivering RF front-end solutions for mobile, infrastructure, and aerospace markets.

The SKY12348-350LF belongs to Skyworks' broadband digital attenuator product line, engineered specifically for high-linearity, low-power RF gain control in 3G/4G/5G infrastructure equipment including macrocells, small cells, and active antennas.

FAQ

What is the absolute maximum RF input power rating for the SKY12348-350LF?

The SKY12348-350LF has an absolute maximum RF input power rating of +30 dBm, as specified in Table 2 of its datasheet. Exceeding this level risks permanent damage. For reliable continuous-wave operation, design margins should maintain peak input power ≤+27 dBm, especially at elevated temperatures or under high-duty-cycle modulated signals. The SKY12348-350LF's +45 dBm IIP3 and +30 dBm P0.1dB ensure headroom for LTE and WiMAX OFDM waveforms with 10 dB PAR.

Does the SKY12348-350LF support bidirectional RF signal flow between RF1 and RF2?

Yes, the SKY12348-350LF supports fully bidirectional RF operation between RF1 and RF2 pins, with symmetric insertion loss (<1.4 dB typ), return loss (>15 dB), and attenuation accuracy across 0.1–3.0 GHz. This enables flexible placement in transceiver architectures - for example, as a transmit-path attenuator before the PA or as a receive-path attenuator after the LNA - without redesigning matching networks. The SKY12348-350LF's internal GaAs pHEMT topology ensures matched performance regardless of signal direction.

What capacitor values are recommended for the RFGND pins on the SKY12348-350LF?

The datasheet specifies that external capacitors must connect RFGND1–RFGND4 (pins 4, 5, 6, 8) to ground to establish the low-frequency cutoff. While exact values depend on target lower band edge, 100 pF is used on the official evaluation board (Figure 9) for operation down to ~700 MHz. For 0.1 GHz operation, ≥1 nF X7R ceramic capacitors are recommended. All capacitors must be placed within 2 mm of respective pins and rated for RF use (low ESL/ESR) to preserve broadband return loss and attenuation flatness. The SKY12348-350LF's performance is validated with these configurations.

Is the SKY12348-350LF pin-compatible with other Skyworks digital attenuators like the SKY12345 series?

No, the SKY12348-350LF is not pin-compatible with the SKY12345 series. Its 16-pin QFN layout (Figure 2) assigns VDD to pin 1, RF1 to pin 2, and V1–V4 to pins 13–16 - whereas SKY12345-360LF uses a different pinout with VDD at pin 16 and control pins distributed elsewhere. PCB layout, decoupling, and grounding schemes differ significantly. Migration requires full schematic and layout revision. The SKY12348-350LF's unique pin mapping is optimized for low-inductance RF routing and thermal dissipation in its 3×3 mm footprint.

What is the guaranteed attenuation accuracy of the SKY12348-350LF across temperature and frequency?

The SKY12348-350LF guarantees attenuation accuracy within ±1.0 dB across its full 0.1–3.0 GHz range and over the –40 °C to +85 °C operating temperature range, as confirmed in Table 3 (e.g., 15 dB max attenuation shows 14.8–15.5 dB typical at 0.7/2.1/2.7 GHz). At 25 °C, step error remains ≤±0.4 dB (Figure 7), and worst-case total error across all 16 states is <±0.8 dB at 2.1 GHz. This accuracy is maintained without external calibration, making the SKY12348-350LF suitable for factory-trimmed and field-adaptive RF systems.