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onsemi NCP1445T
- Part No.:
- NCP1445T
- Manufacturer:
- onsemi
- Package:
- TO-220-7
- Datasheet:
-
NCP1445T.pdf
- Description:
- IC REG BST FLYBCK ADJ 4A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:1,496
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Product details
Overview
NCP1445T from onsemi is a 560 kHz, negative-feedback synchronous boost regulator IC with integrated 4.0 A NPN power switch, operating from 2.7 V to 30 V input and regulating negative output voltages referenced to −2.475 V at the NFB pin. It features current-mode control, thermal shutdown with 25°C hysteresis, frequency foldback under overload, and external synchronization capability up to 1000 kHz - used in portable battery-powered negative rail generation.
For engineers reviewing the NCP1445T datasheet, pinout, applications, or equivalent options, key selection considerations include its 560 kHz switching frequency for compact magnetics, −2.475 V NFB reference tolerance (±0.075 V), 82–92% max duty cycle, 0.68 V typical switch saturation voltage at 4 A, and TO-220-7 T-suffix package thermal performance (θJA = 1.45°C/W on cold plate).
Technical Context
The NCP1445T implements current-mode control using an internal ramp derived from switch current, combined with oscillator-generated slope compensation to prevent subharmonic oscillation above 50% duty cycle. Its dual error amplifier architecture includes a transconductance-based negative feedback path (NFB) with 115–225 mho gain and −2.475 V reference.
Switching is governed by a trimmed 560 kHz oscillator, with frequency foldback triggered when NFB exceeds −0.65 V (e.g., during startup or short-circuit), reducing frequency to 60–160 kHz. The SS pin supports TTL-level sync up to 1000 kHz and logic-low shutdown with ≤60 µA quiescent current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 560 kHz nominal; enables use of <10 µH inductors and <100 nF timing capacitors in compact boost designs. |
| NFB Reference Voltage | −2.475 V ±0.075 V; sets regulated negative output voltage via external resistor divider (e.g., −5 V, −12 V, −15 V rails). |
| Integrated Switch Current | 4.0 A guaranteed; eliminates need for external MOSFET driver and discrete switch in medium-power boost converters. |
| Input Voltage Range | 2.7 V to 30 V; supports single-cell Li-ion (3.0–4.2 V), multi-cell alkaline/NiMH (4.5–12 V), and industrial 24 V bus inputs. |
| Thermal Shutdown | 150–210°C trip range with 25°C hysteresis; protects device during sustained overload without external thermal monitoring. |
| Shutdown Current | ≤60 µA at VCC ≤30 V; enables ultra-low-power standby in battery-backed systems. |
| Max Duty Cycle | 82–92%; constrains minimum input-to-output voltage ratio in boost mode (e.g., limits VIN/|VOUT| ≥ 0.15). |
Pinout & Package
Package: TO-220-7 (Case 821P), thermally enhanced metal-tab package with θJA = 1.45°C/W on cold plate; tab internally connected to GND for heat dissipation and low-inductance grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1. VC | Loop compensation & current limit control | Output of negative error amplifier; RC network here sets loop stability and adjusts current limit threshold via clamp voltage (0.3–1.9 V). |
| 2. TEST | Internal test interface | Must be left floating or grounded; applying 2–6 V disables oscillator while keeping switch active - not for normal operation. |
| 3. NFB | Negative feedback input | Senses scaled negative output voltage; 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 thermal pad; low-impedance path critical for EMI and thermal performance. |
| 5. VSW | Switch collector node | Connects to inductor/diode junction in boost; withstands 40 V; requires short trace to minimize ringing and radiated emissions. |
| 6. SS | Sync/shutdown control | TTL-compatible input: high or open = normal operation; low = shutdown (≤60 µA); rising edge synchronizes to external clock ≤1000 kHz. |
| 7. VCC | Power supply input | 2.7–30 V bias rail; requires local 33 µF low-ESR capacitor to GND for stable startup and transient response. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 4.0 A NPN switch | Eliminates external transistor and gate driver, reducing BOM count and PCB area in space-constrained boost supplies. |
| Current-mode control with slope compensation | Enables stable operation at >50% duty cycle without external compensation components; improves line/load transient response. |
| Frequency foldback under overload | Reduces switching frequency to 60–160 kHz during short-circuit or startup, limiting peak inductor current and component stress. |
| Negative output regulation capability | Directly regulates negative voltages (e.g., −5 V, −12 V) using standard resistor dividers - no inverting op-amp or charge pump required. |
| Thermal shutdown with hysteresis | Auto-recovery after cooling avoids latch-up failure; 25°C hysteresis prevents thermal cycling near trip point. |
Applications
| Portable Negative Rail Generation | Battery-Powered Instrumentation |
|---|---|
|
Use Scenario: Generating −5 V or −12 V from a single 3.7 V Li-ion cell in handheld test equipment. IC Role / Device Role / Timing Role: Primary DC-DC controller regulating negative output via NFB pin; 560 kHz switching enables miniature 4.7 µH shielded inductor. Use Value: Replaces discrete inverting buck-boost + op-amp solution, cutting component count by 6 and board area by 40%. |
Use Scenario: Providing isolated analog front-end bias rails in portable gas analyzers powered by 4×AA batteries (4.5–6.0 V). IC Role / Device Role / Timing Role: Negative voltage source for op-amp dual supplies; uses frequency foldback to survive sensor short-circuit events. Use Value: Maintains −15 V output regulation during 100 ms load dump, preventing ADC reference shift and data corruption. |
| Distributed Power for Industrial Sensors | Embedded System Auxiliary Supply |
|
Use Scenario: Local −10 V generation for piezoelectric sensor bias in factory-floor vibration monitors (24 V input bus). IC Role / Device Role / Timing Role: Standalone boost controller with SS pin synchronized to system clock to reduce EMI in dense PCB layouts. Use Value: Achieves <15 mVpp output ripple at 100 mA load using 22 µF ceramic output cap - meets IEC 61000-4-3 immunity requirements. |
Use Scenario: Secondary negative rail for FPGA I/O bank termination in edge AI gateways (12 V main rail). IC Role / Device Role / Timing Role: Regulator for configurable I/O voltage (−1.2 V to −3.3 V) via precision resistor divider on NFB pin. Use Value: Delivers 300 mA at −2.5 V with <0.5% line regulation across 10–14 V input range - ensures signal integrity in high-speed interfaces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative-output boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM27762 | Charge-pump topology; 200 mA max output; no inductor required; fixed −5 V output. | Limited to low-current, low-noise applications; unsuitable for >200 mA or adjustable negative rails. | Select NCP1445T for >300 mA loads, adjustable outputs, or higher efficiency (>85% at 500 mA) in inductor-based designs. |
| TPS60403 | Charge-pump; 60 mA output; −5 V fixed; 1 MHz switching; integrated LDO post-regulator. | Designed for ultra-low-noise analog rails; cannot support >60 mA or non-standard negative voltages. | Choose NCP1445T when output current >100 mA, input voltage >6 V, or custom negative voltage (e.g., −7.5 V) is required. |
Compared with LM27762 and TPS60403, the NCP1445T delivers 4× higher output current, supports fully adjustable negative outputs via resistor divider, and achieves superior efficiency in medium-power applications - but requires an external inductor and diode.
Availability
NCP1445T is available at Aetrix Electronics and suitable for portable computing, battery-powered instrumentation, distributed industrial sensing, and embedded auxiliary power supply applications requiring stable component supply and long-term production continuity.
Supply support for NCP1445T 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 is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The NCP1445T belongs to onsemi's NCP144x family of high-current boost regulators, designed specifically for compact, high-efficiency DC-DC conversion in space- and power-constrained portable and industrial systems.
FAQ
What is the function of the TEST pin on the NCP1445T?
The TEST pin on the NCP1445T connects to internal test logic and must be left floating or tied to GND during normal operation. Applying a voltage between 2.0 V and 6.0 V disables the internal oscillator while allowing the power switch to remain active - this mode is reserved for factory testing only and must not be used in end-product circuits.
Can the NCP1445T regulate positive output voltages?
No, the NCP1445T is specifically configured for negative output regulation via its NFB pin, which is internally referenced to −2.475 V. For positive-output boost applications, use the pin-compatible NCP1444T (560 kHz, FB pin). The NCP1445T's error amplifier architecture, feedback threshold, and internal biasing are optimized exclusively for negative rail generation.
What is the maximum allowable voltage on the VSW pin of the NCP1445T?
The VSW pin of the NCP1445T has an absolute maximum rating of 40 V. In boost topology, peak VSW voltage equals the regulated negative output magnitude plus diode forward voltage (e.g., 15 V + 0.5 V = 15.5 V for −15 V output with Schottky diode). Exceeding 40 V risks permanent damage; external clamping (e.g., TVS diode to GND) is recommended in flyback or high-VOUT designs.
How does frequency foldback protect the NCP1445T during overload?
When the NFB pin voltage rises above −0.65 V - indicating output overvoltage, short-circuit, or startup surge - the NCP1445T reduces switching frequency from 560 kHz to 60–160 kHz. This extends off-time, lowers average inductor current, and limits power dissipation in both the internal switch and external components without requiring external current-limit circuitry.
Is the NCP1445T RoHS-compliant and lead-free?
Yes, the NCP1445T is manufactured in Pb-free (lead-free) packaging per onsemi's compliance program. The "T" suffix denotes TO-220-7 package with lead-free finish; full RoHS documentation, including substance declarations and soldering profiles, is available in onsemi's Soldering and Mounting Techniques Reference Manual (SOLDERRM/D).
NCP1445T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-7
- Packaging:
- Bag
- 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:
- 560kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-7
NCP1445T FAQ
1.How can I place an order for NCP1445T through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP1445T 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 NCP1445T reliable?
The price and inventory of NCP1445T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP1445T is usually 5 days.
3.What payment methods are accepted for NCP1445T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP1445T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP1445T?
NCP1445T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP1445T 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 NCP1445T?
For technical support, including NCP1445T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP1445T requirements.
6.How does Aetrix verify that NCP1445T is sourced from the original manufacturer or authorized distributors?
All NCP1445T 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 NCP1445T meets industry standards.
7.What is the process for return or replacement of NCP1445T?
All NCP1445T units undergo pre-shipment inspection (PSI). If there is an issue with NCP1445T, 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 NCP1445T part is unused and in its original packaging.
Return procedure for NCP1445T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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