MC13821FCR2 - 2.4GHz ISM/GPS LNA with Bypass | NXP
N.º de pieza: MC13821FCR2 ✗ Fin de vida| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $3.85 | $3,85 |
| 10 | $3.42 | $34,20 |
| 100 | $2.95 | $295,00 |
| 500 | $2.6 | $1.300,00 |
| 1.000 | $2.3 | $2.300,00 |
MC13821FCR2 Descripción general
An LNA (low-noise amplifier) is the first active gain stage in a receiving chain, placed immediately after the antenna and front-end filter. Its primary function is to amplify weak incoming RF signals while adding as little noise as possible, setting the noise floor that downstream mixers and baseband stages must work against. LNAs belong to the broader family of RF amplifiers and, more specifically, integrated RF front-end ICs used in wireless transceivers for cellular, Wi-Fi, GPS, and ISM-band radios.
Key features of the MC13821FCR2 include a wide 1 GHz to 2.4 GHz operating range covering GPS L1, DVB-H, and 2.4 GHz ISM applications; an integrated bypass switch that allows the LNA to be switched out for reduced current draw when high gain is not required; a low 1.45 dB noise figure that preserves receiver sensitivity; and a small 12-pin QFN EP package suitable for space-constrained handheld and mobile designs. The exposed pad provides a low thermal resistance path to the PCB ground.
Technically, the device uses a single-stage cascoded bipolar/SiGe architecture optimized for low noise and high linearity. The bias reference is internally generated and stable over the operating supply range, eliminating the need for an external bias resistor. The bypass switch is implemented with on-chip FETs and is controlled by a CMOS-compatible logic input, allowing direct connection to a baseband or transceiver GPIO.
Typical applications include GPS receiver front-ends in portable navigation devices, 2.4 GHz ISM-band receivers for wireless sensor networks, DVB-H mobile TV tuners, and cellular front-end modules where the bypass function enables current savings during transmit/receive switching. The wide frequency range also makes the part attractive for software-defined radio front-ends requiring a tunable or band-switched LNA.
When designing with this part, pay attention to the input and output matching networks; the device is not internally matched to 50 ohms, so external LC networks are required for optimal noise figure and gain. Also, ensure the bypass logic pin is driven with clean CMOS levels, and route the exposed pad directly to a continuous ground plane for stable RF and thermal performance.
This page synthesizes distributor stock data, drop-in cross-reference candidates, and practical RF design notes that are not present in the manufacturer datasheet.
Alternativas directas para MC13821FCR2 — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con MC13821FCR2 (mismo factor de forma y huella) — difiere en Frequency Range, Input/Output Impedance.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MC13821
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC13820
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX2371ETC+T
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC13821FCR2 Valores máximos y características eléctricas
| Manufacturer | NXP Semiconductors (formerly Freescale) |
| Part Description | Low Noise Amplifier with Bypass Switch |
| RF Type | ISM, GPS |
| Frequency Range | 1 GHz to 2.4 GHz |
| Gain | 16.5 dB (at 2.4 GHz) |
| Noise Figure | 1.45 dB (at 2.4 GHz) |
| Supply Voltage - Operating | 2.75 V |
| Operating Supply Current | 2.8 mA |
| Encapsulado / Carcasa | 12-QFN (3x3 mm) with Exposed Pad |
| Tipo de montaje | Surface Mount |
| Bypass Switch | Yes (logic-controlled) |
| Input/Output Impedance | External matching required (not internally matched to 50 ohms) |
| Estado del ciclo de vida | Obsolete (EOL) |
| Packing | Tape & Reel (suffix R2) |
Configuración de pines de MC13821FCR2
| Pin 1 | RFIN — RF input (external matching required) |
| Pin 2 | GND — Ground |
| Pin 3 | BYPASS — Logic control for bypass mode (CMOS-compatible) |
| Pin 4 | VCC — Supply voltage (2.75 V) |
| Pin 5 | GND — Ground |
| Pin 6 | RFOUT — RF output (external matching required) |
| Pin 7 | NC — Not connected (per datasheet) |
| Pin 8 | NC — Not connected (per datasheet) |
| Pin 9 | NC — Not connected (per datasheet) |
| Pin 10 | GND — Ground |
| Pin 11 | GND — Ground |
| Pin 12 | GND — Ground / exposed pad |
Aplicaciones típicas
MC13821FCR2 es adecuado para 7 aplicacións: GPS Receiver Front-End, 2.4 GHz ISM-Band Receiver, DVB-H Mobile TV Tuner, Wireless Sensor Network Node, Cellular Front-End Module, Software-Defined Radio Front-End, Industrial IoT Gateway.
GPS Receiver Front-End
The MC13821FCR2's 1.45 dB noise figure and 16.5 dB gain at 1.575 GHz make it well-suited as the first LNA stage in GPS L1 receiver chains. Placed between the active GPS antenna and the receiver IC's RF input, the LNA sets the overall cascade noise floor that determines time-to-first-fix and sensitivity to weak satellite signals. The integrated bypass switch allows the GPS receiver to power down the LNA during transmit bursts in coexistent cellular designs, reducing current draw while keeping the RF path intact. With 2.8 mA quiescent current at 2.75 V, the part fits portable navigation devices where low power and small 12-QFN 3x3 mm footprint are mandatory. Alternative candidates: MAX2659, BGU8006.
Recomendado
2.4 GHz ISM-Band Receiver
The MC13821FCR2 is optimized for the 2.4 GHz ISM band used by Wi-Fi, Bluetooth, Zigbee, and proprietary short-range radios. Its 16.5 dB gain at 2.4 GHz and 1.45 dB noise figure let it recover weak signals in long-range or obstructed sensor networks, while the bypass switch enables current savings when high gain is not required (e.g., in short-range or high-RSSI environments). Typical placement is between the antenna and the RF port of a transceiver IC, with LC matching networks on input and output for optimum noise match. Companion ICs in a complete front-end include a SAW filter and a TX/RX switch.
Recomendado
DVB-H Mobile TV Tuner
DVB-H (Digital Video Broadcasting - Handheld) operates in the UHF band with a 1.7 GHz first IF stage, putting the MC13821FCR2's 1 GHz to 2.4 GHz coverage in the right range to amplify the IF signal after the down-conversion mixer. The LNA's 16.5 dB gain compensates for mixer conversion loss and SAW filter insertion loss in the tuner chain, while the 1.45 dB noise figure preserves carrier-to-noise ratio required for robust DVB-H demodulation. The bypass switch supports handheld designers in trading off sensitivity for current savings during video-streaming pauses. The 12-QFN 3x3 mm package fits densely-populated tuner modules.
Recomendado
Wireless Sensor Network Node
Battery-powered WSN nodes (Zigbee, WirelessHART, 6LoWPAN, proprietary sub-GHz/2.4 GHz) require LNAs that deliver low noise figure with the ability to duty-cycle for years of battery life. The MC13821FCR2's bypass mode allows the node to switch off high gain during sleep periods, dropping current consumption while the RF chain remains bypass-ready. The 2.8 mA active current is acceptable for wake-and-listen duty cycles. The 12-QFN 3x3 mm package and exposed thermal pad support compact sensor motes with continuous ground planes for stable RF performance across industrial temperature ranges.
Recomendado
Cellular Front-End Module
In cellular handset front-end modules (FEMs), the MC13821FCR2 can serve as a low-band or diversity receive LNA where its 1 GHz to 2.4 GHz range covers the relevant cellular and PCS/AWS receive bands. The bypass switch lets the FEM drop the LNA from the path during transmit bursts, preventing receiver overload from the PA leakage. Designers integrate the IC with a duplexer, TX/RX switch, and power amplifier on a single laminate module; the part's small 12-QFN footprint suits this high-density integration. Although the part is obsolete, established FEM designs continue to source it for legacy handset platforms.
Recomendado
Software-Defined Radio Front-End
Software-defined radio (SDR) platforms benefit from wideband LNAs that cover multiple bands with external matching swaps. The MC13821FCR2's 1 GHz to 2.4 GHz window supports several SDR use cases including GPS, 2.4 GHz ISM, and parts of the cellular receive range. Designers can swap input/output LC networks to retune the LNA across bands, while the bypass switch enables rapid A/B testing of gain vs. linearity trade-offs in the lab. The exposed thermal pad and small QFN package fit SDR development boards where board real estate is shared between multiple RF chains. Note: this is an EOL part, so new SDR designs should evaluate modern active alternatives.
Recomendado
Industrial IoT Gateway
Industrial IoT gateways aggregate sensor data over multiple wireless protocols, often requiring sensitive receivers for weak signals at the edge of coverage. The MC13821FCR2's 1.45 dB noise figure extends link margin in harsh industrial environments with metal obstructions and EMI. The bypass switch supports gateways that toggle between high-sensitivity listening (LNA on) and low-power idle (LNA bypassed) when no active session is in progress. The 12-QFN 3x3 mm exposed-pad package simplifies thermal management in sealed industrial enclosures. Designers should note the obsolete lifecycle and qualify second-source alternatives for long-lifecycle industrial deployments.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MC13821FCR2 — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MC13821 | MC13820 | MAX2371ETC+T |
|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | Analog Devices (formerly Maxim) |
| Package | 12-QFN (3x3 mm) | 12-QFN (3x3 mm) - same | 12-QFN (3x3 mm) - same | 12-TQFN - similar footprint, verify pin-out |
| Frequency Range | 1 GHz to 2.4 GHz | 1 GHz to 2.4 GHz | Lower band optimized (within family) | 2.4 GHz ISM |
| Bypass Switch | Yes (logic-controlled) | Yes | Yes | Yes |
| Lifecycle Status | Obsolete (EOL) | Obsolete (EOL) | Obsolete (EOL) | Active (per ADI portfolio) |
Diferenciadores clave
- Integrated bypass switch saves BOM and PCB area (frente a Discrete LNA + external SPDT switch)
- Wide 1 GHz to 2.4 GHz coverage spans GPS and ISM bands (frente a MAX2371ETC+T (2.4 GHz ISM only))
- 12-QFN 3x3 mm exposed-pad package supports compact designs (frente a Larger QFN or SOIC-packaged alternatives)
Notas de diseño
The MC13821FCR2 requires external input and output matching networks; the device is NOT internally matched to 50 ohms. Place series L/shunt C (or similar topology) networks within 2-3 mm of the RFIN and RFOUT pins to achieve the 1.45 dB noise figure and 16.5 dB gain specified at 2.4 GHz. Use high-Q 0402 inductors and C0G/NP0 ceramic capacitors for stable RF performance; the Q of the input matching network dominates overall noise figure. Keep all RF traces short and reference them to a continuous ground plane.
The 12-QFN 3x3 mm package has an exposed thermal pad that MUST be soldered directly to a continuous ground plane for both thermal dissipation and RF grounding. Use an array of thermal vias under the pad to the inner ground layer; recommended via pattern is a 3x3 grid of 0.3 mm drilled vias with 0.6 mm pitch. Inadequate thermal pad soldering can raise junction temperature and degrade gain/noise-figure stability over operating life, especially in sealed enclosures with limited airflow.
Do not drive the BYPASS logic pin with a signal that exceeds VCC; CMOS-level logic must be referenced to the same 2.75 V rail as the supply, and logic-low/high thresholds from the datasheet must be observed. Also, do not assume the part is internally 50-ohm matched - omitting input/output matching will cause severe gain loss and noise figure degradation. Estimated: at 2.75 V x 2.8 mA, quiescent power dissipation is approximately 7.7 mW, which is well within the QFN package's thermal limits and does not require additional heatsinking beyond the ground-plane stitching above.
Route the BYPASS control line away from RF traces to avoid capacitive coupling that can modulate the LNA's gain state. If the BYPASS pin is toggled at high speed (e.g., during TDD transmit/receive switching), place a small RC filter on the control line to slow the edge and prevent spurious emissions. Use a dedicated ground pour under the BYPASS trace to minimize digital-to-RF crosstalk in dense PCB layouts. When cascading the LNA with a downstream mixer, ensure inter-stage filtering isolates the LO leakage from the LNA's input.
Información de cumplimiento
Compliance status not explicitly stated in the verified web data. As a legacy Freescale/NXP part, RoHS compliance is likely but should be confirmed via the manufacturer datasheet before use in RoHS-restricted applications. Not AEC-Q100 qualified; not suitable for automotive safety-critical applications without further qualification.
