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SPF5189Z RF Low Noise Amplifier — SOT-89, 50MHz–4GHz, 2.4dB NF, LNA (2-Pack)
SPF5189Z RF Low Noise Amplifier SOT-89, 50MHz–4GHz, 2.4dB NF, LNA (2-Pack)
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SPF5189Z RF Low Noise Amplifier — SOT-89, 50MHz–4GHz, 2.4dB NF, 19dB Gain (2-Pack)
The SPF5189Z is a wideband RF low noise amplifier (LNA) IC in a SOT-89 SMD package, covering 50MHz to 4GHz with 19dB typical gain and 2.4dB noise figure. Designed for receive-path signal amplification, it is widely used in SDR (software-defined radio) front-ends, WiFi range extension, GPS signal amplification, and 2.4GHz/5.8GHz RF circuit design. The single-supply 3–5V operation and 50Ω matched input/output make it easy to integrate into RF signal chains.
Key Specifications
| Parameter | Value |
|---|---|
| Package | SOT-89 (SMD) |
| Frequency Range | 50MHz – 4GHz |
| Gain | 19dB typ. (at 900MHz) |
| Noise Figure (NF) | 2.4dB typ. (at 900MHz) |
| Output IP3 (OIP3) | +27dBm typ. |
| P1dB (output) | +18dBm typ. |
| Supply Voltage | 3V – 5V |
| Supply Current | ~60mA (at 5V) |
| Input/Output Impedance | 50Ω |
| Quantity | 2 pieces |
SPF5189Z vs SKY65111 vs BGA2803 — LNA Comparison
| Feature | SPF5189Z | SKY65111 | BGA2803 |
|---|---|---|---|
| Frequency | 50MHz–4GHz | 0.1–6GHz | 0.05–6GHz |
| Gain | 19dB | 20dB | 20dB |
| Noise Figure | 2.4dB | 1.0dB | 0.7dB |
| Supply | 3–5V | 3–5V | 3.3V |
| Best for | SDR, WiFi, general LNA | Low-noise receive chain | Ultra-low noise, GPS |
Why Choose SPF5189Z?
- 50MHz–4GHz wideband — covers FM (88–108MHz), GSM (900MHz), WiFi (2.4GHz), and 5.8GHz bands
- 19dB gain — significant signal amplification for weak signal reception
- 2.4dB noise figure — low noise for receive-path amplification without degrading SNR
- 3–5V supply — compatible with 3.3V and 5V systems
- 50Ω matched — direct integration into standard 50Ω RF signal chains
Compatible With / Common Use Cases
- SDR (RTL-SDR) front-end: Boost weak signals before RTL2832U dongle for improved sensitivity on HF/VHF/UHF bands
- WiFi range extension: 2.4GHz receive-path LNA for ESP8266/ESP32 external antenna systems
- GPS signal amplification: 1575MHz GPS L1 band signal amplification for weak signal environments
- Ham radio receive: 144MHz (2m) or 432MHz (70cm) band LNA for weak signal reception
- RF module testing: Wideband amplifier for RF lab measurements and signal chain testing
Frequently Asked Questions
Q: How do I bias SPF5189Z for operation?
A: SPF5189Z requires a DC bias on the RF input/output through bias tees (RF choke + DC block capacitor). Connect VCC (3–5V) through a 100nH RF choke to the output port. Add 100pF DC block capacitors on input and output for AC coupling. The IC is internally matched to 50Ω — no external matching network needed for 50Ω systems. Refer to the SPF5189Z datasheet application circuit for the complete bias network.
Q: Can SPF5189Z be used as a transmit amplifier?
A: SPF5189Z is designed as a receive LNA (low noise amplifier), not a power amplifier. Its P1dB of +18dBm limits transmit power to ~60mW. For transmit amplification, use a dedicated PA (power amplifier) IC such as SKY65135, RFX2401C, or SE2431L. Using an LNA in transmit mode may damage the IC if input power exceeds the P1dB compression point.
Q: What PCB layout considerations are needed for SPF5189Z?
A: Use a 50Ω microstrip transmission line (width depends on PCB substrate — ~2.9mm on FR4 at 1.6mm thickness). Keep RF traces short and direct. Place decoupling capacitors (100pF + 10nF) close to the VCC pin. Use a solid ground plane under the RF traces. Avoid routing digital signals near RF traces to prevent interference.
Package Contents
- 2× SPF5189Z RF Low Noise Amplifier IC (SOT-89)
