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onsemi NCP112P
- Part No.:
- NCP112P
- Manufacturer:
- onsemi
- Category:
- Supervisors
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
NCP112P.pdf
- Description:
- IC SUPERVISOR 4 CHANNEL 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,471
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Product details
Overview
NCP112P from onsemi is a supervisory IC designed for desktop ATX power supply monitoring, providing simultaneous overvoltage and undervoltage detection for 3.3 V, 5.0 V, and 12 V rails with ±0.2 V thresholds, 20 mA fault sink capability, and programmable delays using 100 nF capacitors. It integrates a 2.5 V precision voltage reference and supports remote on/off control in multi-output SMPS systems.
For engineers reviewing the NCP112P datasheet, pinout, applications, or equivalent options, key selection criteria include its triple-rail monitoring accuracy, adjustable UV blanking (100–500 ms), power good delay (100–500 ms), and compatibility with legacy TSM112-based designs in PDIP-14 packaging.
Technical Context
The NCP112P implements independent comparator-based OV/UVP circuits for each monitored rail (VS33/VS5/VS12), all referenced to a stable 1.28 V internal threshold with built-in hysteresis (40–130 mV). Its fault logic latches after a 100 µs delay to reject transient spikes, and the FAULT output drives external PWM controllers directly via open-collector sinking.
Timing functions-undervoltage blanking (CTUV), remote on/off (CTREMOTE), and power good assertion (CTPG)-are implemented using internal current sources charging external 100 nF capacitors, enabling linear, predictable delay tuning across temperature (−40°C to +125°C ambient).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 4.5 V to 16 V - Supports wide-input ATX auxiliary rails without external regulation. |
| 3.3 V OV Threshold | 4.0 V typical - Matches ATX spec limit of +15% for 3.3 V rail; hysteresis prevents chatter near trip point. |
| 5.0 V UV Threshold | 2.5 V typical - Detects 25% drop below nominal; ensures system reset before CPU core voltage collapse. |
| 12 V OV Hysteresis | 130 mV - Provides noise immunity against switching ripple on high-current 12 V outputs. |
| VREF Output | 2.50 V ±0.04 V @ 1 mA - Stable reference for external comparators or ADC biasing; 20 mA sourcing enables driving multiple loads. |
| FAULT Sink Current | 20 mA minimum - Directly interfaces with standard PWM enable/disable pins without level-shifting or buffering. |
| Operating Temperature | −40°C to +125°C junction - Validated for use inside thermally stressed PSU enclosures near transformers and MOSFETs. |
Pinout & Package
Package: PDIP-14 (Case 646, P suffix), Pb-free, through-hole mount. Dimensions: 19.56 mm × 6.60 mm × 4.69 mm (L × W × H).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VS33) | 3.3 V Sense Input | Monitors main 3.3 V output; triggers OV/UVP when voltage deviates beyond ±15% with hysteresis. |
| 2 (VS5) | 5.0 V Sense Input | Monitors +5 V rail; detects faults per ATX specification with 100 mV hysteresis for noise rejection. |
| 3 (VS12) | 12 V Sense Input | Monitors +12 V rail; 130 mV hysteresis accommodates high-current load transients without false trips. |
| 4 (ADJ) | Adjustable OVP Input | Additional OV monitor with 1.28 V threshold; ORed into fault logic for custom rail supervision. |
| 5 (PGI) | Power Good Input | External logic input (e.g., thermal shutdown signal); forces PGO low if asserted, overriding rail status. |
| 6 (CTUV) | UV Blanking Timing Capacitor | Configures 100–500 ms blanking window during power-up to prevent premature UV fault assertion. |
| 7 (GND) | Ground Reference | Common return for all analog comparators and digital logic; requires low-impedance PCB connection. |
| 8 (VREF) | Voltage Reference Output | 2.5 V precision source; supplies bias for external circuitry or calibration references without loading. |
| 9 (REMOTE) | Remote On/Off Control | Active-low reset input; internally pulled up to 3.4 V; initiates latch reset after fault condition clears. |
| 10 (CTREMOTE) | Remote Delay Timing Capacitor | Sets 35–60 ms on/off delay; ensures clean sequencing between motherboard and PSU control signals. |
| 11 (CTPG) | Power Good Delay Capacitor | Configures 100–500 ms PGO assertion delay; guarantees all rails stabilize before system boot proceeds. |
| 12 (PGO) | Power Good Output | Open-collector active-high signal; indicates all monitored rails are within spec and PGI is valid. |
| 13 (FAULT) | Fault Output | Open-collector active-high signal; asserts when any OV/UVP condition or ADJ fault occurs. |
| 14 (VCC) | Power Supply Input | Accepts 4.5–16 V; powers internal comparators, reference, and logic; decoupling capacitor required. |
Key Features
| Feature | Design Value |
|---|---|
| Triple-rail OV/UVP detection | Simultaneous monitoring of 3.3 V, 5.0 V, and 12 V outputs with rail-specific thresholds and hysteresis per ATX compliance. |
| Programmable timing with 100 nF caps | Eliminates need for precision timing resistors; reduces BOM cost and layout complexity while ensuring repeatable delays. |
| 2.5 V precision reference (20 mA) | Enables accurate external voltage scaling or ADC reference without external regulators or buffers. |
| Remote on/off with internal pull-up | 3.4 V internal pull-up on REMOTE pin simplifies motherboard interface; no external resistor needed for default high state. |
| 100 µs fault delay filtering | Rejects sub-100 µs voltage spikes common in switch-mode operation, preventing nuisance shutdowns during transient events. |
Applications
| Desktop ATX Power Supply Monitoring | Industrial Multi-Rail SMPS Supervision |
|---|---|
|
Use Scenario: Real-time monitoring of 3.3 V, 5.0 V, and 12 V outputs in ATX-compliant PC power supplies during startup, load transients, and fault conditions. IC Role / Device Role / Timing Role: Central supervisory controller that asserts FAULT to disable PWM and pulls PGO low until all rails stabilize within ±5% tolerance. Use Value: Ensures motherboard receives reliable power-good signaling and prevents boot under out-of-spec conditions, meeting ATX 2.31 requirements. |
Use Scenario: Supervising isolated DC-DC converter outputs in industrial PLC power modules where multiple regulated rails feed I/O, logic, and analog sections. IC Role / Device Role / Timing Role: Fault coordinator that combines rail status, thermal input (via PGI), and remote reset to manage system-level power sequencing and safety interlocks. Use Value: Enables deterministic power-up order and graceful shutdown on overvoltage, reducing field failure rates in harsh EMI environments. |
| Legacy TSM112 Replacement | Embedded System Power Sequencing |
|
Use Scenario: Drop-in upgrade path for existing designs using TSM112, leveraging identical pinout and enhanced hysteresis for improved noise immunity. IC Role / Device Role / Timing Role: Pin-compatible supervisory IC delivering tighter OV/UVP thresholds (±0.2 V vs ±0.25 V) and extended temperature range (−40°C to +125°C). Use Value: Extends product lifecycle without PCB redesign; reduces qualification effort while improving reliability in high-temperature deployments. |
Use Scenario: Coordinating power delivery to FPGA, memory, and peripheral ICs in compact embedded systems requiring staggered rail activation. IC Role / Device Role / Timing Role: Timing sequencer using CTUV, CTPG, and CTREMOTE to enforce precise delay intervals between 12 V → 5 V → 3.3 V ramp-up. Use Value: Prevents back-powering and latch-up in mixed-voltage SoCs by enforcing strict voltage monotonicity during startup. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisory IC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL331IDR | Single comparator only; no integrated triple-rail monitoring, no PGO/FAULT logic, no timing capacitors. | Requires external components to replicate NCP112P functionality; not suitable for ATX-compliant power-good generation. | Select only for custom supervisory designs where full integration is unnecessary and board space allows discrete implementation. |
| MAX6816EPA+ | Quad debounced switch input; lacks voltage monitoring, reference output, or power-good delay capability. | Designed for mechanical switch conditioning-not for analog rail supervision or SMPS control loop integration. | Not functionally comparable; avoid for power supply monitoring applications requiring rail-specific OV/UVP detection. |
Compared with TL331IDR and MAX6816EPA+, the NCP112P delivers complete, single-chip ATX power supply supervision-including triple-rail monitoring, programmable delays, 2.5 V reference, and fault coordination-eliminating design complexity and validation risk in desktop and industrial SMPS systems.
Availability
NCP112P is available at Aetrix Electronics and suitable for desktop PC power supplies, industrial multi-rail SMPS units, and embedded system power sequencing requiring stable component supply, long-term lifecycle support, and Pb-free compliance.
Supply support for NCP112P 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 silicon solutions for automotive, industrial, cloud, medical, and edge applications.
The NCP112P belongs to onsemi's power management supervisory IC product line, engineered specifically for robust, standards-compliant monitoring of multi-output switch-mode power supplies in computing and industrial equipment.
FAQ
What is the primary function of the NCP112P in a power supply system?
The NCP112P serves as a dedicated supervisory IC that continuously monitors the 3.3 V, 5.0 V, and 12 V outputs of an ATX-compliant switch-mode power supply. It asserts the FAULT signal to disable the main PWM controller upon detecting overvoltage or undervoltage conditions and generates a delayed PGO signal only when all rails remain within specification for the programmed time window. This ensures safe, compliant power delivery to downstream systems.
Does the NCP112P require external components to operate, and which ones are mandatory?
Yes, the NCP112P requires three external 100 nF ceramic timing capacitors (CTUV, CTREMOTE, CTPG) to set undervoltage blanking, remote on/off, and power good delays. It also needs a 0.1 µF VCC bypass capacitor and optional pull-down resistors on VS33/VS5/VS12 for rail sensing. No external resistors are needed for threshold setting-the NCP112P uses internal 1.28 V references for all comparators.
How does the NCP112P handle noise on monitored power rails?
The NCP112P incorporates built-in hysteresis on all sense inputs (VS33, VS5, VS12, ADJ, PGI): 40–130 mV for OV and 100 mV for UV detection. It also includes a 100 µs fault delay to filter short-duration spikes. These features collectively suppress false triggering caused by switching noise, load transients, or EMI-ensuring reliable operation without external RC filtering.
Can the NCP112P be used outside of ATX desktop power supplies?
Yes, the NCP112P is applicable in any multi-output SMPS requiring coordinated rail supervision, such as industrial PLC power modules, telecom rectifiers, or test equipment supplies. Its −40°C to +125°C operating range, programmable delays, and 2.5 V reference make it suitable for non-ATX systems-but users must validate timing and threshold settings against their specific rail tolerances and sequencing requirements.
What is the role of the PGI (Power Good Input) pin on the NCP112P?
The PGI pin on the NCP112P provides an additional logic-level input-typically connected to a thermal sensor or secondary fault indicator-that overrides the PGO output. When PGI falls below 1.28 V, PGO is forced low regardless of rail status, ensuring the system halts boot or initiates shutdown even if all voltages are nominal but another critical condition (e.g., overtemperature) exists. This extends supervision beyond voltage alone.
NCP112P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 4
- Voltage - Threshold:
- 3.3V, 5V, 12V, Adj
- Output:
- Open Drain or Open Collector
- Reset:
- Active High
- Reset Timeout:
- Adjustable/Selectable
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-PDIP
NCP112P FAQ
1.How can I place an order for NCP112P through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP112P 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 NCP112P reliable?
The price and inventory of NCP112P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP112P is usually 5 days.
3.What payment methods are accepted for NCP112P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP112P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP112P?
NCP112P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP112P 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 NCP112P?
For technical support, including NCP112P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP112P requirements.
6.How does Aetrix verify that NCP112P is sourced from the original manufacturer or authorized distributors?
All NCP112P 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 NCP112P meets industry standards.
7.What is the process for return or replacement of NCP112P?
All NCP112P units undergo pre-shipment inspection (PSI). If there is an issue with NCP112P, 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 NCP112P part is unused and in its original packaging.
Return procedure for NCP112P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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