ATR4251-EK - AM/FM Antenna Amplifier Eval Kit | Microchip/Atmel
MPN: ATR4251-EK β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $186.45 | $186.45 |
| 10 | $186.45 | $1,864.50 |
| 100 | $186.45 | $18,645.00 |
| 500 | $186.45 | $93,225.00 |
| 1,000 | $186.45 | $186,450.00 |
ATR4251-EK Overview
An antenna amplifier evaluation kit is a hardware development board that allows RF and automotive audio engineers to benchmark an antenna amplifier IC before committing to a custom PCB design. In the car radio signal chain, the antenna amplifier sits between the passive antenna element (windshield or roof antenna) and the tuner front-end, boosting weak AM and FM signals while maintaining low noise and high linearity. Evaluation kits like the ATR4251-EK belong to the broader hierarchy of RF development tools, evaluation boards, and development kits.
The kit showcases the ATR4251's headline features: high dynamic range for both AM and FM reception, integrated automatic gain control (AGC) for AM and FM, a high third-order intercept point (IP3) with adjustable FM amplifier settings, adjustable cable impedance matching, and high second- and third-order intercept points for the AM path. These characteristics minimize intermodulation distortion in strong-signal environments such as dense urban traffic.
Technically, the underlying ATR4251 integrates the low-noise amplifier, AGC loops, and biasing in a single BiCMOS2S die, reducing external component count versus discrete antenna amplifier solutions. The AGC automatically reduces gain under strong input signals, preventing overload of downstream tuner stages, while the low noise figure preserves sensitivity for weak-station reception at the edge of coverage.
Typical evaluation scenarios include car radio tuner front-end prototyping, windshield and roof active-antenna module design, benchmarking against competing antenna amplifier ICs, and educational RF lab work on AGC behavior.
A key design consideration when evaluating this kit is supply and interface compatibility with the target tuner module, as cable impedance matching is adjustable and must be configured to match the measurement or vehicle harness.
This page synthesizes distributor pricing, datasheet-derived specifications, application guidance, and sourcing notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATR4251-EK β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
No drop-in alternatives available for this product.
Request AlternativesATR4251-EK Specifications (manufacturer-published)
| Product Type | Antenna Amplifier Evaluation Kit |
| Associated IC | ATR4251 |
| IC Technology | BiCMOS2S |
| IC Function | Low-noise, high-dynamic-range AM/FM antenna amplifier with integrated AGC |
| Reception Bands | AM and FM |
| AGC | Integrated, AM and FM |
| Target Application | Automotive car radio, windshield and roof antennas |
| FM Linearity | High third-order intercept point (IP3), adjustable |
| AM Linearity | High second- and third-order intercept points |
| Impedance Matching | Adjustable to various cable impedances |
| RoHS Status | RoHS Non-Compliant |
| Lead Free Status | Contains Lead |
ATR4251-EK Interfaces & Connectors
No manufacturer-published interface list is available for ATR4251-EK. Refer to the manufacturer documentation for connector and header details.
Refer to the manufacturer documentation for the full expansion header pinout and connector pin numbering.
Typical Applications
ATR4251-EK is suitable for 6 applications: Car Radio Tuner Front-End Evaluation, Windshield Antenna Module Development, Roof (Shark-Fin) Antenna Module Design, RF Laboratory Benchmarking and Comparison, Educational RF and AGC Laboratory Work, Legacy Car Radio Service and Retrofits.
Car Radio Tuner Front-End Evaluation
The ATR4251-EK is purpose-built for evaluating AM/FM reception in automotive car radio tuner front-ends. According to the ATR4251 datasheet, the underlying IC is designed in particular for car applications, providing high dynamic range, integrated AM and FM AGC, and high second- and third-order intercept points that suppress intermodulation when the vehicle passes strong broadcast transmitters. On the evaluation board, engineers connect the antenna source and tuner measurement equipment, then characterize noise, gain, and AGC step behavior across both bands. Because the FM amplifier intercept point is adjustable and cable-impedance matching is configurable, the kit allows the front-end to be tuned to the exact harness geometry of the target vehicle platform. This quantified flexibility - adjustable IP3 and impedance matching - is the primary reason to validate a car radio design on the ATR4251-EK before layout.
Recommended
Windshield Antenna Module Development
Windshield-printed antennas present unusual impedance and low signal levels, making a low-noise amplifier with adjustable matching essential. The ATR4251 addresses this directly: the datasheet states the device is suitable for windshield antennas, and its impedance matching is adjustable to various cable impedances, accommodating the atypical feed impedance of printed glass antennas. Engineers use the ATR4251-EK to insert the amplifier between a simulated or real windshield feed and the tuner, measuring how the integrated AGC maintains linearity under strong FM signals common in urban driving. The high second- and third-order intercept points for AM minimize cross-modulation from adjacent strong stations. Validating the matching network values on the evaluation kit reduces redesign cycles when the circuit moves to the production antenna module PCB.
Recommended
Roof (Shark-Fin) Antenna Module Design
Roof-mounted shark-fin antenna modules integrate the active amplifier close to the antenna element, then drive a long coaxial cable to the head unit. The ATR4251's adjustable cable-impedance matching lets designers optimize the amplifier output network for the specific coax length and characteristic impedance of the module, while the low-noise, high-dynamic-range amplifier preserves weak-station reception. Using the ATR4251-EK, engineers emulate this configuration in the lab: the amplifier is configured for the target cable impedance, and AGC action is verified against strong-signal tests, since roof antennas are exposed to high field strengths near transmitters. The integrated AM/FM AGC in the BiCMOS2S die eliminates the discrete AGC circuitry that would otherwise add cost and board area inside the compact shark-fin enclosure.
Recommended
RF Laboratory Benchmarking and Comparison
The ATR4251-EK serves as a reference platform for benchmarking AM/FM antenna amplifier candidates. Its published feature set - high dynamic range, integrated dual-band AGC, adjustable FM third-order intercept point, and high AM intercept points - provides a measurable baseline against which competitor amplifier ICs can be compared on identical test fixtures. Engineers can sweep input level to characterize AGC transfer, measure IP3 under two-tone excitation, and record noise-limited sensitivity for weak-signal reception. The 21-page ATR4251 datasheet supplies the nominal operating conditions needed to standardize these measurements. Using a vendor evaluation board rather than a custom fixture removes layout variability from the comparison, giving procurement and design teams defensible data for second-source or redesign decisions in automotive audio platforms.
Recommended
Educational RF and AGC Laboratory Work
Because the ATR4251-EK exposes an integrated AGC loop on both AM and FM paths, it is well suited to teaching automatic gain control behavior in RF receivers. Students can drive the board from a signal generator, sweep input amplitude across several decades, and observe how the integrated AGC compresses gain to keep the output within the tuner's linear range - a practical demonstration of concepts like dynamic range, intercept point, and blocking. The adjustable FM amplifier intercept point provides a hands-on parameter to explore the linearity-versus-gain trade-off, while the adjustable impedance matching exercises basic impedance-transformer design. The BiCMOS2S integration also illustrates how modern mixed-signal processes combine low-noise RF amplification and control functions on a single die for automotive-grade designs.
Recommended
Legacy Car Radio Service and Retrofits
For service organizations maintaining legacy Atmel-based car radio platforms, the ATR4251-EK doubles as a diagnostic fixture to verify whether reception faults originate in the antenna amplifier stage or the tuner. Because the kit reproduces the datasheet reference circuit with the ATR4251 and its AGC, a technician can substitute the kit for the suspect on-board amplifier and compare sensitivity and intermodulation performance. Note that the kit is listed as RoHS non-compliant and containing lead, so it is appropriate for bench service of existing equipment rather than incorporation into newly manufactured units destined for RoHS-regulated markets. Its adjustable impedance matching also lets one bench fixture serve multiple vehicle harness types.
Recommended
Recommended Products Summary
Engineering reference data for ATR4251-EK β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product |
|---|---|
| Package | Evaluation board (kit) - not an IC package |
| Brand | Atmel (Microchip Technology) |
| Product Type | Antenna Amplifier Eval Kit |
| Associated IC | ATR4251 (BiCMOS2S) |
| Reception Bands | AM and FM |
| Integrated AGC | Yes (AM and FM) |
| Unit Price (qty 1, as of 2026-09-19) | US $186.45 |
| RoHS Status | Non-Compliant (contains lead) |
Key Differentiators
- Dual-band integrated AGC in one IC (vs Discrete AGC antenna amplifier solutions)
- Adjustable cable-impedance matching (vs Fixed-impedance antenna amplifier designs)
- High linearity for strong-signal environments (vs Lower-dynamic-range amplifiers)
Design Notes
The ATR4251-EK is an evaluation tool, not a production component: distributor data (DigChip) lists it as RoHS non-compliant and containing lead. Do not incorporate the board into end products shipped to RoHS-regulated markets. Use it strictly for laboratory characterization of the ATR4251 IC, then design the IC itself into the production PCB with a compliant bill of materials.
When transferring the evaluation circuit to a production design, reproduce the RF layout geometry - short, controlled-impedance runs from the antenna feed to the amplifier input and from the output to the tuner - and set the adjustable cable-impedance matching network to the actual coax characteristics of the vehicle harness. Verify the transferred matching values with a network analyzer, since the datasheet application values assume the evaluation board layout.
Exploit the AGC and intercept-point adjustability during characterization: sweep input level across the full AM and FM dynamic range to map AGC gain reduction, and measure two-tone IP3 at each adjustable FM setting. This produces the linearity-versus-gain data needed to finalize the amplifier configuration before committing to the production tuner front-end, and quantifies headroom against strong-signal blocking in urban environments.
Compliance Information
Per DigChip distributor specification data: Lead Free Status: Contains Lead; RoHS Status: RoHS Non-Compliant. Applies to the evaluation kit as listed.