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onsemi NCP1443T
- Part No.:
- NCP1443T
- Manufacturer:
- onsemi
- Package:
- TO-220-7
- Datasheet:
-
NCP1443T.pdf
- Description:
- IC REG BST FLYBCK ADJ 4A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:3,227
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Product details
Overview
NCP1443T from onsemi is a 280 kHz fixed-frequency, current-mode boost regulator IC with integrated 4.0 A NPN power switch, negative feedback input (NFB), and −2.475 V internal reference-designed for inverting and negative-output DC-DC conversion in battery-powered systems. It operates from 2.7 V to 30 V input, delivers up to 4.0 A switch current, and features thermal shutdown with hysteresis, frequency foldback under overload, and external synchronization capability.
For engineers reviewing the NCP1443T datasheet, pinout, applications, or equivalent options, key selection considerations include its −2.475 V NFB reference voltage, 280 kHz base switching frequency, TO-220–7 (T suffix) package with exposed metal pad for thermal dissipation, and compatibility with inverting, SEPIC, and flyback topologies requiring negative regulation.
Technical Context
The NCP1443T implements current-mode control using a slope-compensated PWM architecture, where the oscillator-derived ramp is summed with the sensed switch current to stabilize operation above 50% duty cycle. Its transconductance error amplifier (115–225 mho) drives the VC pin for loop compensation and current limit setting.
It supports dual operating modes: nominal 280 kHz switching (with 90–96% max duty cycle) and reduced-frequency mode (30–120 kHz) triggered when NFB exceeds −0.65 V-enabling safe startup and short-circuit protection. The SS pin provides TTL-compatible sync up to 500 kHz and logic-low shutdown with ≤60 µA quiescent current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 280 kHz nominal; drops to 30–120 kHz during NFB overvoltage-reduces stress during overload or short circuit. |
| NFB Reference Voltage | −2.475 V (typ); sets regulated negative output voltage via external resistor divider at NFB pin. |
| Integrated Switch Current Limit | 4.0 A guaranteed minimum; clamped by internal emitter resistors and VC-controlled transconductance amplifier. |
| Input Voltage Range | 2.7 V to 30 V; supports wide-range battery inputs (e.g., 3-cell Li-ion, 12 V automotive rail). |
| Thermal Shutdown Threshold | 150–210 °C with 25 °C hysteresis; prevents latch-up and enables self-recovery after cooling. |
| Shutdown Current | ≤60 µA at VCC ≤30 V; enables ultra-low-power standby in portable systems. |
| Max VSW Rating | 40 V; allows use in boost topologies with up to ~39.5 V output (accounting for diode VF). |
Pinout & Package
Package: TO-220–7 (T suffix), Case 821P, with exposed metal pad thermally and electrically connected to GND pin (Pin 4) for enhanced heat dissipation and low-impedance grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1. VC | Loop compensation & current limit control | Output of transconductance error amplifier; RC network here sets bandwidth and limits peak switch current. |
| 2. TEST | Internal test logic interface | Must be left floating or grounded; voltage between 2.0–6.0 V disables oscillator and holds switch ON. |
| 3. NFB | Negative feedback input | Senses regulated negative output; referenced to −2.475 V; triggers frequency foldback if > −0.65 V. |
| 4. GND | Power and signal ground | Common return for controller, switch emitter, and exposed metal pad-critical for thermal and EMI performance. |
| 5. VSW | Switch collector node | High-current (up to 4.0 A) open-collector output; connects to inductor/diode in boost or transformer primary in flyback. |
| 6. SS | Sync input / shutdown control | TTL-compatible; low = shutdown (≤60 µA); rising edge synchronizes oscillator up to 500 kHz. |
| 7. VCC | Power supply input | Accepts 2.7–30 V; requires local bypass capacitor to GND for stable bias and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Negative-output regulation support | Integrated −2.475 V reference and NFB pin enable direct sensing and regulation of negative voltages without external op-amps. |
| Frequency foldback under fault | Automatically reduces switching frequency to 20% of nominal when NFB > −0.65 V-limits energy per cycle during overload or short circuit. |
| Thermal shutdown with hysteresis | Triggers at 150–210 °C and resets only after ≥25 °C cooldown-prevents thermal cycling and ensures reliable recovery. |
| External synchronization | SS pin accepts TTL pulses up to 500 kHz, enabling multi-rail power supply phase alignment and EMI reduction. |
| Current-mode control with slope compensation | Eliminates subharmonic oscillation above 50% duty cycle while providing inherent cycle-by-cycle current limiting. |
Applications
| Inverting Power Supply | Negative Bias Generator |
|---|---|
Use Scenario: Generating −5 V or −12 V from a single 5 V or 12 V rail in analog instrumentation or op-amp circuits. IC Role / Device Role / Timing Role: Primary controller in inverting buck-boost topology; regulates negative output via NFB pin and sets switching timing via internal 280 kHz oscillator. Use Value: Eliminates need for isolated DC-DC or charge-pump ICs-reduces BOM count and improves efficiency over capacitive inverters at >100 mA loads. |
Use Scenario: Providing clean, adjustable negative bias for LCD contrast control, RF front-end biasing, or sensor signal conditioning. IC Role / Device Role / Timing Role: Negative-output boost regulator; uses NFB feedback and VC compensation to maintain tight regulation despite load transients. Use Value: Delivers stable −2.5 V to −15 V outputs with <±1% line/load regulation-enables precision analog subsystems without external LDO post-regulation. |
| Portable Computer Power Rail | Battery-Powered Test Equipment |
Use Scenario: Generating auxiliary negative rails (e.g., −3.3 V) for USB PHY, audio codec, or display driver ICs in laptops and tablets. IC Role / Device Role / Timing Role: High-efficiency boost-inverting regulator; leverages wide 2.7–30 V input range to operate across depleted Li-ion battery (3.0–4.2 V/cell). Use Value: Achieves >85% efficiency at 1 A output with minimal external components-extends runtime and reduces thermal load in space-constrained enclosures. |
Use Scenario: Powering handheld multimeters, portable oscilloscopes, or field-deployable sensors requiring dual ±12 V rails from 4×AA batteries. IC Role / Device Role / Timing Role: Core switching controller in dual-output inverting/boost configuration; uses SS pin for synchronized dual-channel operation. Use Value: Supports cold-start down to 2.2 V input and maintains regulation through full battery discharge-enables uninterrupted measurement accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative-output switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM27762 | Charge-pump inverter (no inductor); 200 mA max output; fixed −5 V or adjustable via resistor. | Limited to low-current, low-noise applications; unsuitable for >250 mA or high-efficiency requirements. | Choose LM27762 only for ultra-compact, low-noise, sub-200 mA negative rails where inductor-free design is mandatory. |
| NCP1445T | Same pinout and package; 560 kHz switching frequency; identical NFB architecture and −2.475 V reference. | Enables smaller magnetics and lower output ripple but increases switching losses at high current. | Select NCP1445T when board space is constrained and higher frequency permits smaller inductors/capacitors-verify thermal margin at full 4 A load. |
Compared with LM27762 and NCP1445T, the NCP1443T offers optimal balance of high-current capability (4.0 A), thermal robustness (TO-220–7), and 280 kHz operation-making it ideal for medium-power inverting supplies where efficiency, cost, and thermal management outweigh ultra-small size or highest switching frequency.
Availability
NCP1443T is available at Aetrix Electronics and suitable for battery-powered systems, portable computing power rails, and industrial inverting DC-DC converters requiring stable component supply across long production lifecycles.
Supply support for NCP1443T 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, delivering power management, analog, and sensing solutions for automotive, industrial, and cloud infrastructure markets.
The NCP1443T belongs to onsemi's NCP144x family of high-current, wide-input switching regulators-designed specifically for flexible, high-efficiency DC-DC conversion in portable, battery-backed, and distributed power applications.
FAQ
What is the function of the NFB pin on the NCP1443T?
The NFB (Negative Feedback) pin on the NCP1443T senses the regulated negative output voltage and compares it to an internal −2.475 V reference. When the voltage at NFB rises above −0.65 V-indicating overvoltage-the NCP1443T automatically reduces switching frequency to 20% of nominal for protection. This pin replaces the need for external error amplifiers in negative-output designs.
Can the NCP1443T be used in a standard boost configuration to generate positive voltage?
No-the NCP1443T is not designed for positive-output boost operation. It lacks a positive FB pin and internal 1.276 V reference; its feedback architecture is exclusively optimized for negative-output topologies (inverting, flyback, SEPIC). For positive boost, use NCP1442T or NCP1444T instead.
What is the maximum allowable voltage on the VSW pin of the NCP1443T?
The VSW pin of the NCP1443T has an absolute maximum rating of 40 V. In boost topology, this limits the achievable output to approximately VOUT(MAX) ≈ 39.5 V (accounting for Schottky diode forward voltage). Exceeding 40 V risks permanent damage-even transient spikes must be clamped with TVS or RCD snubbers.
How does the VC pin affect current limiting in the NCP1443T?
The VC pin on the NCP1443T sets the peak switch current limit via internal transconductance amplification. Its voltage determines the clamp threshold: VC = ISW × 0.015 Ω × 5.0 V/V. Connecting an external shunt from VC to GND lowers the effective clamp voltage-and thus reduces the current limit below the nominal 4.0 A.
Is the NCP1443T RoHS-compliant and lead-free?
Yes-the NCP1443T is offered in Pb-free (lead-free) packaging per onsemi's compliance program. The "T" suffix denotes TO-220–7 package with lead-free finish, qualified to JEDEC J-STD-020 moisture sensitivity level (MSL) 3 and compatible with standard reflow soldering profiles up to 230 °C peak.
NCP1443T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-7
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Boost, Flyback, Forward Converter, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- -
- Voltage - Output (Max):
- -
- Current - Output:
- 4A (Switch)
- Frequency - Switching:
- 280kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-7
NCP1443T FAQ
1.How can I place an order for NCP1443T through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP1443T 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 NCP1443T reliable?
The price and inventory of NCP1443T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP1443T is usually 5 days.
3.What payment methods are accepted for NCP1443T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP1443T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP1443T?
NCP1443T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP1443T 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 NCP1443T?
For technical support, including NCP1443T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP1443T requirements.
6.How does Aetrix verify that NCP1443T is sourced from the original manufacturer or authorized distributors?
All NCP1443T 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 NCP1443T meets industry standards.
7.What is the process for return or replacement of NCP1443T?
All NCP1443T units undergo pre-shipment inspection (PSI). If there is an issue with NCP1443T, 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 NCP1443T part is unused and in its original packaging.
Return procedure for NCP1443T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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