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Allegro MicroSystems CTD418-50AC
- Part No.:
- CTD418-50AC
- Manufacturer:
- Allegro MicroSystems
- Category:
- Sensor Evaluation Boards
- Package:
- Datasheet:
-
CTD418-50AC.pdf
- Description:
- EVAL BOARD FOR CT418
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
CTD418-50AC from Allegro MicroSystems is a high-bandwidth, ultra-low-noise contact current sensor using XtremeSense™ TMR technology for precise DC/AC current measurement in isolated power systems. It supports ±50 A current range with 40 mV/A sensitivity, ≤±3.0% full-scale total output error, and 1 MHz bandwidth - enabling real-time motor control and solar inverter protection.
For engineers reviewing the CTD418-50AC datasheet, CTD418-50AC pinout, CTD418-50AC application, or CTD418-50AC equivalent, this page delivers verified specifications, SOIC-8 terminal mapping, isolation-rated design context, and validated alternative parts for industrial and automotive current sensing.
Technical Context
The CTD418-50AC integrates a current-carrying conductor (CCC) rated for ±65 A peak, with factory-calibrated analog output referenced to 2.50 V quiescent voltage for bipolar operation. Its TMR-based sensing core achieves <13.5 mARMS noise at 100 kHz and –54 dB common-mode field immunity.
It features an open-drain FLT pin activated within 250 ns on overcurrent detection (OCD threshold = ±55 A), plus UVLO (2.45–2.50 V) and 100 µs power-on stabilization - all operating across –40°C to +125°C with AEC-Q100 Grade 1 qualification and UL/IEC 62368-1 reinforced isolation (2.5 kVRMS).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Current Range | ±50 A - supports bidirectional AC/DC current monitoring in motor drives and inverters without external shunt or amplifier. |
| Sensitivity | 40 mV/A - enables direct interface with 12-bit ADCs (e.g., 2 V full-scale span yields ~50 LSB/A resolution). |
| Total Output Error | ≤±3.0% FS - guaranteed over –40°C to +125°C, including lifetime drift, ensuring stable calibration in harsh environments. |
| Bandwidth | 1 MHz - captures fast transients (e.g., IGBT switching edges) with <300 ns response time for real-time fault detection. |
| Isolation Rating | 2.5 kVRMS dielectric withstand - certified to UL 1577 and IEC 62368-1, enabling safe integration into 400 VAC mains-connected systems. |
| Supply Voltage | 4.75–5.50 V - compatible with standard 5 V industrial rails and tolerant of ±5% regulation variation. |
| Noise Density | 14.0 mARMS @ 100 kHz - low enough to resolve sub-amp load changes in telecom PSUs and UPS systems. |
Pinout & Package
CTD418-50AC is housed in an industry-standard 8-lead SOIC package (4.89 mm × 6.00 mm × 1.62 mm), green and RoHS-compliant, with creepage/clearance ≥4 mm and internal isolation barrier ≥110 µm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 | IP+ | Primary conductor input (high-side current path); carries up to ±65 A; must be routed with low-inductance PCB traces. |
| 3, 4 | IP− | Primary conductor return (low-side current path); completes CCC loop; symmetric layout required for field cancellation. |
| 5 | GND | Analog ground reference for signal chain; separate from power ground to maintain isolation integrity. |
| 6 | FLT | Open-drain fault output (active-low); asserts within 250 ns on OCD or UVLO; requires external 10 kΩ pull-up to VCC. |
| 7 | OUT | Analog voltage output (0.5–4.5 V); linearly proportional to sensed current; 100 pF max capacitive load supported. |
| 8 | VCC | 5 V supply input; bypassed internally and externally (1 µF ceramic); powers TMR sensor and analog front-end. |
Key Features
| Feature | Design Value |
|---|---|
| XtremeSense™ TMR sensing | Enables <13.5 mARMS noise and –54 dB common-mode rejection - critical for accurate current measurement near high-dv/dt switching nodes. |
| Integrated CCC with 1 mΩ resistance | Eliminates external shunt losses and thermal drift; supports continuous 50 A RMS with minimal self-heating (<1.5°C rise). |
| Reinforced isolation (2.5 kVRMS) | Meets safety requirements for Class I equipment in solar inverters and EV chargers without additional isolation components. |
| Factory-trimmed sensitivity & offset | Reduces system-level calibration effort; ±2 mV offset error at 25°C enables single-point zero-current adjustment in production test. |
| OCD with hysteresis (±10%) | Prevents chatter during transient overloads; FLT pin asserts at ±55 A and clears at ±45 A - suitable for IGBT short-circuit protection. |
Applications
| Solar Inverter DC Link Monitoring | Industrial Motor Drive Phase Current Sensing |
|---|---|
Use Scenario: Real-time bidirectional current measurement on DC bus of string inverters handling up to 10 kW. IC Role / Device Role / Timing Role: Isolated analog current sensor providing 1 MHz bandwidth feedback to DSP for MPPT and anti-islanding control. Use Value: Enables <300 ns fault detection and ±50 A range coverage without external amplification or isolation barriers. |
Use Scenario: High-accuracy phase current sampling in 3-phase PMSM drives for field-oriented control (FOC). IC Role / Device Role / Timing Role: Bipolar current sensor with 2.5 V quiescent output feeding ADC inputs synchronized to PWM carrier. Use Value: Delivers ≤±3.0% FS error across –40°C to +125°C, eliminating temperature-dependent gain recalibration. |
| Telecom PSU Overcurrent Protection | EV Onboard Charger Input Monitoring |
Use Scenario: Primary-side current monitoring in 3 kW telecom rectifiers with fast transient response requirements. IC Role / Device Role / Timing Role: Fault-aware current sensor triggering shutdown via FLT pin within 250 ns of overcurrent event. Use Value: Integrates OCD, UVLO, and isolation in one SOIC-8 package - reducing BOM count vs. shunt+isolator+comparator solution. |
Use Scenario: Input AC current sensing in 11 kW OBCs with reinforced isolation for functional safety compliance (ISO 26262 ASIL-B). IC Role / Device Role / Timing Role: Reinforced-isolated current sensor meeting UL 62368-1 working voltage (280 VRMS) for basic + reinforced insulation. Use Value: Eliminates need for external isolation amplifiers while maintaining 2.5 kVRMS surge withstand per IEC 61000-4-5. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar contact current sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ACS724LLCTR-50AB-T | Based on Hall-effect; 100 kHz bandwidth; ±1.5% typical error; no integrated OCD pin. | Lacks FLT output and 1 MHz bandwidth - unsuitable for fast-switching IGBT protection or high-fidelity FOC. | Select when cost sensitivity outweighs bandwidth and integrated fault signaling needs. |
| TMC157A-LA | Based on TMR; ±50 A range; 40 mV/A; but only 200 kHz bandwidth and no UL-certified isolation. | Requires external isolation for mains-connected systems; not qualified for automotive or safety-critical use. | Choose for non-isolated, space-constrained embedded applications where certification is not required. |
Compared with ACS724LLCTR-50AB-T and TMC157A-LA, CTD418-50AC uniquely combines UL-certified 2.5 kVRMS isolation, 1 MHz bandwidth, integrated OCD with FLT pin, and AEC-Q100 Grade 1 qualification - making it the only option qualified for automotive-grade OBCs and safety-certified solar inverters.
Availability
CTD418-50AC is available at Aetrix Electronics and suitable for solar inverters, industrial motor drives, and EV onboard chargers requiring stable component supply with long-term lifecycle support and traceable sourcing.
Supply support for CTD418-50AC 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
Allegro MicroSystems is a U.S.-based semiconductor company specializing in magnetic sensing and power ICs, with decades of leadership in current sensing and motion control solutions.
The CT418 product line was designed specifically for high-accuracy, isolated current measurement in safety-critical power conversion systems - targeting solar, EV, industrial automation, and telecom infrastructure markets.
FAQ
What is the primary current range supported by CTD418-50AC?
CTD418-50AC supports a ±50 A bidirectional current range, with factory-calibrated sensitivity of 40 mV/A and guaranteed total output error ≤±3.0% full-scale across –40°C to +125°C. This range is optimized for motor phase current sensing and DC-link monitoring in 5–10 kW power converters.
Does CTD418-50AC require external filtering components?
Yes - CTD418-50AC requires a 1.0 µF X5R ceramic bypass capacitor (CBYP) between VCC and GND, and a 1.0 nF filter capacitor (CFLT) from FLT to GND if the fault pin is used. These values are specified in the datasheet to ensure stable operation and noise immunity.
How is isolation performance validated for CTD418-50AC?
CTD418-50AC is 100% production-tested for 1 second at 2.5 kVRMS per UL 62368-1 (edition 2) and UL 1577. It achieves reinforced isolation with 280 VRMS working voltage, 4 mm creepage/clearance, and 110 µm internal DTI - fully documented in its isolation ratings table.
Can CTD418-50AC replace shunt-based current sensing in existing designs?
Yes - CTD418-50AC replaces shunt resistors, isolation amplifiers, and external comparators in many applications. Its integrated CCC eliminates power loss and thermal drift, while the FLT pin and analog output simplify interface design versus discrete solutions requiring signal conditioning.
What is the quiescent output voltage (VOQ) of CTD418-50AC?
The quiescent output voltage (VOQ) of CTD418-50AC is 2.495–2.505 V at TA = 25°C and IP = 0 A, centered at 2.500 V to support symmetric ±50 A measurement. This rail-to-rail compatible output spans 0.5–4.5 V, enabling direct connection to most 5 V ADCs without level-shifting.
CTD418-50AC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- XtremeSense™ Crocus Technology
- Packaging:
- Box
- Product Status:
- Active
- Sensor Type:
- Current Sensor
- Sensing Range:
- ±50A
- Interface:
- Analog
- Sensitivity:
- 40mV/A
- Voltage - Supply:
- 4.75V ~ 5.5V
- Embedded:
- No
- Contents:
- Board(s)
- Utilized IC / Part:
- CT418
CTD418-50AC FAQ
1.How can I place an order for CTD418-50AC through Aetrix?
Please submit a Request for Quotation (RFQ) for CTD418-50AC on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for CTD418-50AC reliable?
The price and inventory of CTD418-50AC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CTD418-50AC is usually 5 days.
3.What payment methods are accepted for CTD418-50AC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CTD418-50AC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CTD418-50AC?
CTD418-50AC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CTD418-50AC order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for CTD418-50AC?
For technical support, including CTD418-50AC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CTD418-50AC requirements.
6.How does Aetrix verify that CTD418-50AC is sourced from the original manufacturer or authorized distributors?
All CTD418-50AC products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that CTD418-50AC meets industry standards.
7.What is the process for return or replacement of CTD418-50AC?
All CTD418-50AC units undergo pre-shipment inspection (PSI). If there is an issue with CTD418-50AC, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The CTD418-50AC part is unused and in its original packaging.
Return procedure for CTD418-50AC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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