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Texas Instruments LM2578AN/NOPB
- Part No.:
- LM2578AN/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2578AN/NOPB.pdf
- Description:
- IC REG BUCK BOOST 750MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,095
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Product details
Overview
LM2578AN/NOPB from Texas Instruments is a monolithic switching regulator controller IC featuring an integrated NPN output transistor, dual comparator inputs (inverting and non-inverting), internal 1.0 V reference, and on-chip oscillator. It supports buck, boost, and inverting DC-DC topologies with up to 750 mA output current, 2 V to 40 V input range, and duty cycle up to 90%. It is used in industrial power supplies requiring compact, low-component-count voltage conversion.
For engineers reviewing the LM2578AN/NOPB datasheet, LM2578AN/NOPB pinout, LM2578AN/NOPB application, or LM2578AN/NOPB equivalent, key selection considerations include its fixed 1.0 V reference accuracy, ground- or VIN-referenced current limit sensing, collector-emitter sustaining voltage of 60 V, and thermal shutdown with junction temperature limit of 150 °C.
Technical Context
The LM2578AN/NOPB implements a pulse-width modulation (PWM) control architecture with a unique dual-input comparator stage that provides independent inverting and non-inverting terminals-each internally biased to 1.0 V-enabling direct feedback without external op-amps in inverting configurations. Its oscillator frequency is set by a single external capacitor (20 kHz typical with 3900 pF) and features blanking to enforce ≤90% maximum duty cycle.
It integrates a high-current NPN output transistor with collector saturation voltage ≤0.9 V at 750 mA (pulsed), emitter saturation voltage ≤1.7 V at 80 mA, and collector-emitter sustaining voltage of 60 V. Current limiting operates cycle-by-cycle with 110 mV sense threshold referenced either to ground or VIN, and includes thermal shutdown and overcurrent protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2 V to 40 V - supports wide industrial input rails including 3.3 V, 5 V, 12 V, and 24 V systems without pre-regulation. |
| Output Current Capability | Up to 750 mA (pulsed) - enables direct drive of medium-power loads like sensors, actuators, or auxiliary rails without external pass transistors. |
| Oscillator Frequency | 20 kHz typical (CT = 3900 pF); adjustable from <1 Hz to 100 kHz - allows EMI optimization and inductor size trade-offs. |
| Reference Voltage | 1.0 V ±1% (25 °C), ±2% over −40 °C to +85 °C - ensures stable feedback threshold for precise output regulation across temperature. |
| Current Limit Threshold | 110 mV (±30 mV) - sets overcurrent trip point via external sense resistor; configurable for ground- or VIN-referenced sensing. |
| Collector Saturation Voltage | ≤0.9 V at 750 mA - minimizes conduction loss in high-duty-cycle buck applications. |
| Thermal Shutdown | Activates at TJ ≥150 °C - protects device during overload or poor heatsinking conditions. |
Pinout & Package
LM2578AN/NOPB is housed in an 8-pin plastic DIP (Dual In-line Package), package code P0008E per TI documentation. This through-hole package supports prototyping and legacy industrial PCBs with standard 0.3-inch row spacing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Feedback (Inverting Input) | Comparator inverting input terminal | Accepts regulated output voltage feedback; internally referenced to 1.0 V; used in buck and inverting configurations. |
| 2 - Ground | Power and signal reference node | Common return path for internal circuitry, current limit sense (if ground-referenced), and external components. |
| 3 - Current Limit | Overcurrent sense input | Triggers cycle-by-cycle shutdown when voltage deviates >110 mV from ground or VIN; enables flexible current sensing placement. |
| 4 - Oscillator Timing | Oscillator capacitor connection | Connects external timing capacitor (CT) to set switching frequency; internal charge/discharge currents define fOSC = 8×10⁻⁵/CT. |
| 5 - Emitter Output | NPN transistor emitter terminal | Provides low-side switch node; must not be driven >1 V below ground (0.6 V above 100 °C junction) to avoid unintended turn-on. |
| 6 - Collector Output | NPN transistor collector terminal | High-side switch node; rated for 50 V max to ground; supports boost and buck-boost topologies with external diode. |
| 7 - Non-Inverting Input | Comparator non-inverting input terminal | Accepts reference or error signal; internally biased to 1.0 V; used for remote sensing or custom control loops. |
| 8 - VIN | Main supply input | Power input for internal circuitry and output transistor base drive; operates from 2 V to 40 V; supports under-voltage lockout via external network. |
Key Features
| Feature | Design Value |
|---|---|
| Dual comparator inputs with 1.0 V reference | Eliminates need for external op-amp in inverting regulators and simplifies feedback network design for buck/boost. |
| Adjustable oscillator (1 Hz–100 kHz) | Enables EMI compliance tuning and optimal inductor sizing without changing IC; single capacitor sets frequency. |
| Ground- or VIN-referenced current limit | Supports both low-side and high-side current sensing topologies, improving layout flexibility and noise immunity. |
| Integrated thermal shutdown | Prevents permanent damage during sustained overload or inadequate thermal management in enclosed industrial enclosures. |
| 90% maximum duty cycle | Enables high step-down ratios in buck converters (e.g., 24 V → 3.3 V) without requiring external duty cycle clamping. |
Applications
| Buck Regulator | Boost Regulator |
|---|---|
Use Scenario: Stepping down 12 V or 24 V industrial bus to 5 V or 3.3 V for microcontrollers and I/O peripherals. IC Role / Device Role / Timing Role: PWM controller generating gate drive for external MOSFET or internal NPN switch; regulates output via feedback to Pin 1. Use Value: Achieves >75% efficiency at 350 mA load with minimal external parts-only inductor, diode, capacitor, and two resistors required. | Use Scenario: Generating 15 V bias rail from a 5 V USB or logic supply in portable test equipment. IC Role / Device Role / Timing Role: Controller driving external diode and inductor; uses Pin 6 (collector) as switching node and Pin 5 (emitter) as return path. Use Value: Delivers 140 mA at 15 V with 10 mV ripple using Schottky diode and 330 µH inductor-no transformer or isolated topology needed. |
| Inverting Regulator | Motor Speed Control |
Use Scenario: Creating −15 V rail from +5 V input for RS-232 transceivers or op-amp biasing in instrumentation. IC Role / Device Role / Timing Role: Configured with feedback to Pin 7 (non-inverting) and output inversion via Pin 5–6 topology; regulates negative output magnitude. Use Value: Provides 300 mA at −15 V with 44 mV load regulation-avoids dual-output ICs or discrete inverter stages. | Use Scenario: Controlling speed of small DC motors (e.g., fans, pumps) in HVAC or factory automation panels. IC Role / Device Role / Timing Role: PWM generator modulating average motor voltage; uses Pin 6 (collector) to drive motor high-side via external NPN/PNP pair. Use Value: Enables smooth 0–100% speed control with built-in current limiting to protect motor windings during stall conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2577-ADJ | Fixed-frequency (52 kHz) PWM controller with internal 3.75 V reference; requires external NPN transistor; no dual comparator inputs. | Designed for fixed-output boost/buck-boost only; lacks inverting regulator support and flexible feedback architecture. | Select when needing higher efficiency at fixed frequency and external transistor isolation is preferred. |
| UC3843N | Current-mode PWM controller with 1 A peak output drive; 1 V reference; requires external oscillator components; no integrated current limit sense threshold. | Used in flyback and forward converters; supports higher power levels but demands more external circuitry for basic DC-DC functions. | Select when designing isolated topologies or requiring precise current-mode control with external MOSFET drivers. |
Compared with LM2578AN/NOPB, LM2577-ADJ offers higher integration for boost-only designs but lacks inverting capability and dual-input flexibility, while UC3843N provides superior current-mode stability for transformer-based designs but increases BOM count and layout complexity for simple non-isolated regulators.
Availability
LM2578AN/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, motor control interfaces, instrumentation bias generation, and embedded DC-DC conversion requiring stable component supply and long-term manufacturability.
Supply support for LM2578AN/NOPB 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of experience in industrial-grade power ICs.
The LM2578A product line was designed specifically for cost-sensitive, medium-power non-isolated DC-DC conversion in industrial, automotive, and consumer applications where simplicity, reliability, and wide input range are critical.
FAQ
What is the maximum input voltage rating for LM2578AN/NOPB?
The LM2578AN/NOPB has an absolute maximum total supply voltage rating of 50 V, with recommended operating input voltage from 2 V to 40 V. Exceeding 40 V during normal operation risks exceeding internal transistor breakdown limits and may trigger premature thermal shutdown. The 50 V absolute maximum is a stress rating only and not intended for continuous use.
Does LM2578AN/NOPB support inverting regulator configurations?
Yes, LM2578AN/NOPB explicitly supports inverting regulator topologies, as confirmed in TI's SNVS767E datasheet Figure 33 and Application Note "Inverting Regulator." Its dual comparator inputs (Pins 1 and 7) and internal 1.0 V reference allow direct feedback of the negative output without external polarity reversal circuitry, enabling efficient −5 V or −15 V generation from positive inputs.
What is the purpose of Pin 3 (Current Limit) on LM2578AN/NOPB?
Pin 3 is the current limit sense input that triggers cycle-by-cycle shutdown when its voltage deviates by more than 110 mV from either ground or VIN. This enables flexible overcurrent protection: grounding the sense resistor yields ground-referenced sensing, while connecting it to VIN enables high-side sensing. The 110 mV threshold remains constant across temperature with ±30 mV tolerance.
Can LM2578AN/NOPB operate with an input voltage below 2 V?
No, LM2578AN/NOPB is not specified to operate below 2 V. The datasheet defines 2 V as the minimum operating input voltage, and performance-including reference accuracy, oscillator stability, and output transistor drive-is not guaranteed below this level. Attempting sub-2 V operation may result in erratic switching, failure to start, or undefined comparator behavior.
What package type does LM2578AN/NOPB use, and is it RoHS compliant?
LM2578AN/NOPB uses an 8-pin plastic DIP (dual in-line package), package code P0008E. The "/NOPB" suffix indicates lead-free (RoHS-compliant) finish per TI's packaging nomenclature. It meets JEDEC J-STD-020 moisture sensitivity level 1 and is rated for through-hole reflow or wave soldering per IPC-J-STD-001.
LM2578AN/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost
- Output Type:
- -
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- -
- Voltage - Output (Max):
- -
- Current - Output:
- 750mA (Switch)
- Frequency - Switching:
- 20kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LM2578AN/NOPB FAQ
1.How can I place an order for LM2578AN/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2578AN/NOPB 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 LM2578AN/NOPB reliable?
The price and inventory of LM2578AN/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2578AN/NOPB is usually 5 days.
3.What payment methods are accepted for LM2578AN/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2578AN/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2578AN/NOPB?
LM2578AN/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2578AN/NOPB 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 LM2578AN/NOPB?
For technical support, including LM2578AN/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2578AN/NOPB requirements.
6.How does Aetrix verify that LM2578AN/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2578AN/NOPB 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 LM2578AN/NOPB meets industry standards.
7.What is the process for return or replacement of LM2578AN/NOPB?
All LM2578AN/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2578AN/NOPB, 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 LM2578AN/NOPB part is unused and in its original packaging.
Return procedure for LM2578AN/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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