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onsemi MC34166TVG
- Part No.:
- MC34166TVG
- Manufacturer:
- onsemi
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
MC34166TVG.pdf
- Description:
- IC REG BUCK BST ADJ 3.3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,358
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Product details
Overview
MC34166TVG from onsemi is a fixed-frequency voltage-mode switching regulator IC designed for step-down, voltage-inverting, and cost-effective step-up DC-DC converter applications. It integrates a 72 kHz oscillator, 5.05 V ±2% reference, latching PWM, high-gain error amplifier, and 3.0 A output switch, operating from 7.5 V to 40 V input with cycle-by-cycle current limiting and thermal shutdown. It delivers regulated 5.05 V output without external resistor divider in basic configurations.
For engineers reviewing the MC34166TVG datasheet, pinout, applications, or equivalent options, this page provides verified technical context, real-world design values, package-specific layout guidance, and validated alternative options for automotive, industrial, and embedded power supply designs requiring stable 3 A switching regulation.
Technical Context
The MC34166TVG implements voltage-mode control using an internal 72 kHz oscillator with 95% max duty cycle, where the error amplifier output modulates PWM conduction via comparison against the oscillator ramp. Its 5.05 V reference is internally connected to the non-inverting input of the error amplifier and not brought out to a pin.
Cycle-by-cycle current limiting monitors switch current via an internal trimmed sense resistor and comparator, resetting the PWM latch at ≥3.3 A (typical 4.3 A) peak. Undervoltage lockout activates at 5.9 V (±0.4 V hysteresis), and thermal shutdown triggers at ~170°C, disabling the output switch until junction temperature falls below recovery threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 72 kHz nominal; enables predictable EMI filtering and compact magnetics sizing in step-down/inverting topologies. |
| Reference Voltage | 5.05 V ±2% at +25°C; sets base output voltage without external feedback divider in standard 5 V applications. |
| Output Switch Current | 3.0 A continuous; supports up to 3 A load in TO-220 package with heatsink, limited by thermal resistance (θJA = 65°C/W). |
| Input Voltage Range | 7.5 V to 40 V; accommodates 12 V automotive systems and industrial 24 V rails with margin for transients. |
| Duty Cycle Range | 0% to 95%; allows wide output voltage adjustment in step-down (VOUT < VIN) and inverting (VOUT < 0) modes. |
| Standby Supply Current | 36 µA at 12 V; achieved by clamping Pin 5 (Compensation) below 0.15 V, enabling low-power sleep mode. |
| Current Limit Threshold | 4.3 A typical; protects switch during overload or short-circuit events with cycle-by-cycle response. |
Pinout & Package
MC34166TVG uses a 5-lead TO-220 vertical-mount package (Case 314B), with the metal tab electrically connected to Pin 3 (Ground). The package is Pb-free and moisture sensitivity level (MSL) 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Ground (GND) | Power ground reference for internal circuits; must be low-impedance connection to minimize noise coupling into error amp. |
| Pin 2 | Switch Output (SW) | Collector of internal NPN power transistor; connects to inductor in step-down or to emitter in inverting configuration. |
| Pin 3 | Ground / Heatsink Tab | Common ground and thermal path; tab is electrically tied to Pin 3 and must be mounted to heatsink with thermal interface material. |
| Pin 4 | Supply Input (VCC) | Primary power input (7.5–40 V); powers internal circuitry and bias networks; requires local 330 µF bypass capacitor. |
| Pin 5 | Compensation (Comp) | Error amplifier output; used for loop compensation (RF/CF) and standby mode control (clamp <0.15 V). |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 72 kHz oscillator with on-chip timing | Eliminates external timing components; ensures consistent switching frequency across temperature and supply variations. |
| 5.05 V precision reference (±2%) | Enables accurate 5 V output without external resistors; compensates for typical 1% cable drop in end equipment. |
| 95% maximum duty cycle | Supports high step-down ratios (e.g., 24 V → 5 V) and efficient voltage inversion with minimal dead time loss. |
| Cycle-by-cycle current limiting | Provides immediate overcurrent protection per switching cycle, preventing thermal runaway during fault conditions. |
| Undervoltage lockout with hysteresis | Ensures clean startup above 5.9 V and prevents oscillation near threshold via 0.9 V hysteresis band. |
Applications
| Automotive Body Control Module | Industrial PLC I/O Power Supply |
|---|---|
Use Scenario: Regulating 12 V battery input to stable 5 V for microcontroller, CAN transceiver, and sensor interfaces in under-hood modules. IC Role / Device Role / Timing Role: Primary step-down switching controller driving external inductor and Schottky diode; manages transient load steps up to 3 A. Use Value: Delivers 82.8% efficiency at 3 A/12 V input, with built-in UVLO preventing brownout resets and thermal shutdown avoiding damage during prolonged overloads. | Use Scenario: Generating isolated ±12 V and +5 V rails from 24 V DC bus in programmable logic controller backplanes. IC Role / Device Role / Timing Role: Core voltage-inverting regulator (Figure 23) producing −12 V/1.0 A, paired with step-down stages for auxiliary outputs. Use Value: Achieves ±0.017% load regulation on −12 V rail and 81.2% efficiency, with internal 5.05 V reference ensuring accuracy across −40°C to +70°C ambient range. |
| Consumer Audio Power Stage | Off-Line AC-DC Preconverter |
Use Scenario: Providing clean, low-noise 5 V supply for digital signal processors and DACs in portable audio amplifiers. IC Role / Device Role / Timing Role: Step-down regulator with soft-start (via Pin 5 current source) minimizing inrush; configured with low-ESR output capacitor for <10 mVpp ripple. Use Value: Meets 10 mVpp ripple spec at full 3 A load, and line regulation of ±0.05% across 8–36 V input, critical for analog audio fidelity. | Use Scenario: High-efficiency 24 V pre-regulator stage fed from rectified AC line via flyback transformer in multi-output SMPS. IC Role / Device Role / Timing Role: Post-regulator controlling secondary-side output after transformer isolation; operates in self-oscillating 50 kHz preconverter architecture (Figure 28). Use Value: Enables 90% system efficiency and independent regulation of three outputs (5 V/2 A, 12 V/300 mA, −12 V/100 mA) with total 83.3% efficiency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC33166TVG | Wider operating temperature range (−40°C to +85°C vs. 0°C to +70°C); identical electrical specs and pinout. | Suitable for extended-temperature industrial or automotive underhood use where MC34166TVG's 0°C lower limit is insufficient. | Select MC33166TVG when ambient operation below 0°C is required; otherwise MC34166TVG offers same performance at lower cost. |
| LM2576T-5.0 | Fixed 5 V output, 3 A switch, 52 kHz frequency; includes internal diode, different compensation scheme, and no inverting capability. | Limited to step-down only; lacks voltage-inverting topology support and adjustable duty cycle beyond fixed 5 V. | Choose LM2576T-5.0 for simpler 5 V step-down designs where inverting or wide-duty flexibility is unnecessary. |
Compared with MC33166TVG, MC34166TVG trades extended temperature range for cost and availability in commercial-grade applications; compared with LM2576T-5.0, it offers topology flexibility (step-down/inverting/step-up) and higher oscillator frequency but requires external diode and more complex compensation.
Availability
MC34166TVG is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power supplies, consumer audio DC-DC conversion, and off-line preconverter designs requiring stable component supply and long-term manufacturability.
Supply support for MC34166TVG 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 manufacturer specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and IoT applications.
The MC34166TVG belongs to onsemi's legacy monolithic switching regulator product line, engineered for robust, low-component-count DC-DC conversion in cost-sensitive and thermally constrained environments.
FAQ
What is the maximum output current capability of the MC34166TVG?
The MC34166TVG features an internal 3.0 A output switch, supporting up to 3 A continuous load in step-down or inverting configurations when properly heatsinked. Actual achievable current depends on PCB copper area, ambient temperature, and thermal resistance - with θJA = 65°C/W, sustained 3 A operation requires careful thermal design. Peak switch current limit is typically 4.3 A.
Can the MC34166TVG be used in voltage-inverting applications?
Yes, the MC34166TVG is explicitly designed for voltage-inverting configurations, as confirmed in its datasheet title and Figure 23. It achieves negative output by re-referencing the IC ground pin to the negative output rail, allowing stable −12 V/1.0 A generation with 81.2% efficiency and ±0.017% load regulation.
What is the purpose of Pin 5 (Compensation) on the MC34166TVG?
Pin 5 serves dual functions: it is the error amplifier output used for loop compensation (via RF/CF network), and it enables low-power standby mode when clamped below 0.15 V - reducing supply current to 36 µA. This pin also supports soft-start via its internal 100 µA pull-up current source charging an external capacitor.
Does the MC34166TVG require external components for basic 5 V regulation?
No - the MC34166TVG provides a 5.05 V ±2% internal reference and can deliver regulated 5 V output without any external feedback resistors in standard step-down configurations (Figure 19). External components (inductor, diode, input/output capacitors, compensation network) remain necessary for power conversion functionality.
What protection features does the MC34166TVG include?
The MC34166TVG integrates cycle-by-cycle current limiting, undervoltage lockout (5.9 V startup with 0.9 V hysteresis), internal thermal shutdown (~170°C), and low-power standby mode. These features collectively prevent damage from overloads, input brownouts, overheating, and idle-state power waste - all without requiring external protection circuitry.
MC34166TVG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-5 Formed Leads
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 7.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 5.05V
- Voltage - Output (Max):
- 40V (Switch)
- Current - Output:
- 3.3A (Switch)
- Frequency - Switching:
- 72kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
MC34166TVG FAQ
1.How can I place an order for MC34166TVG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC34166TVG 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 MC34166TVG reliable?
The price and inventory of MC34166TVG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC34166TVG is usually 5 days.
3.What payment methods are accepted for MC34166TVG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC34166TVG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC34166TVG?
MC34166TVG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC34166TVG 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 MC34166TVG?
For technical support, including MC34166TVG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC34166TVG requirements.
6.How does Aetrix verify that MC34166TVG is sourced from the original manufacturer or authorized distributors?
All MC34166TVG 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 MC34166TVG meets industry standards.
7.What is the process for return or replacement of MC34166TVG?
All MC34166TVG units undergo pre-shipment inspection (PSI). If there is an issue with MC34166TVG, 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 MC34166TVG part is unused and in its original packaging.
Return procedure for MC34166TVG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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