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onsemi MC33166TVG
- Part No.:
- MC33166TVG
- Manufacturer:
- onsemi
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
MC33166TVG.pdf
- Description:
- IC REG BUCK BST ADJ 3.3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,398
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Product details
Overview
MC33166TVG from onsemi is a fixed-frequency, voltage-mode switching regulator IC designed for step-down and voltage-inverting DC-DC converter topologies. It integrates a 72 kHz oscillator, 5.05 V ±2% reference, high-gain error amplifier, latching PWM comparator, and 3.0 A output switch - enabling compact, low-component-count power supplies operating from 7.5 V to 40 V input in industrial and automotive environments.
For engineers reviewing the MC33166TVG datasheet, pinout, applications, or equivalent options, this page delivers verified technical context, real-world design parameters, thermal and protection behavior, and validated alternative options - all grounded in the official onsemi Rev. 9 datasheet (August 2024) and ordering documentation.
Technical Context
The MC33166TVG implements voltage-mode control with an internal 5.05 V reference applied to the non-inverting input of the error amplifier. Its oscillator generates a fixed 72 kHz ramp (62–79 kHz over temperature), driving a latching PWM that supports 0–95% duty cycle and cycle-by-cycle current limiting at 3.3–6.0 A peak switch current.
Protection includes undervoltage lockout with 5.9 V startup threshold and 0.9 V hysteresis, thermal shutdown at ~170°C junction, and standby mode reducing supply current to 36 µA when compensation pin voltage drops below 0.15 V - all implemented without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 72 kHz nominal (62–79 kHz over −40°C to +85°C); sets minimum inductor size and EMI profile. |
| Reference Voltage | 5.05 V ±2% at 25°C; enables stable 5.0 V output without external divider in basic step-down designs. |
| Switch Current Capability | 3.0 A continuous output switch; supports up to 4.3 A typical current limit threshold for transient overload protection. |
| Input Voltage Range | 7.5 V to 40 V; accommodates 12 V/24 V automotive and industrial rails with headroom for transients. |
| Operating Temperature | −40°C to +85°C ambient; qualified for extended industrial and automotive under-hood applications. |
| Standby Supply Current | 36 µA at 12 V; enables low-power sleep modes via compensation pin clamping below 0.15 V. |
| UVLO Threshold | 5.9 V startup with 0.9 V hysteresis; prevents erratic operation during brown-out or cold-cranking conditions. |
Pinout & Package
MC33166TVG is housed in a Pb-free 5-lead TO-220 package (Case 314B), with the metal tab thermally and electrically connected to Pin 3 (Ground). The vertical-mount leadform supports heatsinking directly to chassis or PCB copper.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Compensation | Output of error amplifier; connects to RC network for loop stability; <0.15 V enables 36 µA standby mode. |
| Pin 2 | Switch Output | Collector of internal NPN power transistor; drives external inductor in step-down/inverting configurations. |
| Pin 3 | Ground | Power and signal ground reference; tied internally to heatsink tab for thermal conduction and EMI control. |
| Pin 4 | VCC | Positive supply input (7.5–40 V); powers internal circuitry and provides bias for oscillator and reference. |
| Pin 5 | Feedback | Inverting input of error amplifier; compares output voltage (via resistor divider) against 5.05 V reference. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 5.05 V reference | ±2% accuracy at 25°C enables precise output regulation without trimming; compensates for 1% cable drop in 5 V systems. |
| Fixed 72 kHz oscillator | On-chip timing eliminates external capacitor; ensures consistent switching frequency across temperature and supply variations. |
| Cycle-by-cycle current limiting | Monitors switch current every cycle and disables conduction immediately upon exceeding 3.3–6.0 A threshold - preventing MOSFET or inductor saturation damage. |
| Undervoltage lockout with hysteresis | Starts operation only above 5.9 V and holds until VCC falls to 5.0 V, eliminating chattering during power-up or battery sag. |
| Thermal shutdown | Activates at ~170°C junction temperature to force latch reset - safeguarding device during sustained overload or inadequate heatsinking. |
| Low-power standby mode | Reduces ICC to 36 µA by clamping Pin 1 voltage; supports system-level energy management without disabling upstream regulators. |
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 interface circuits in door modules or lighting controllers. IC Role / Device Role / Timing Role: Primary step-down switching regulator providing isolated, ripple-controlled 5 V rail with UVLO immunity to cold-cranking dips. Use Value: Eliminates need for external current-sense resistor and timing capacitor; achieves >82% efficiency at 3 A load per onsemi Figure 19 test data. |
Use Scenario: Generating −12 V auxiliary rail from 24 V DC bus to power op-amps, analog front-ends, and isolated RS-485 transceivers in programmable logic controllers. IC Role / Device Role / Timing Role: Voltage-inverting regulator configured per Figure 23, using internal reference and feedback architecture to regulate negative output without external reference. Use Value: Delivers 1.0 A at −12 V with 81.2% efficiency and ±0.017% load regulation - validated in onsemi's published test results. |
| Off-Line AC-DC Preconverter | Dual-Output Telecom Power |
|
Use Scenario: Serving as post-regulator in offline flyback-derived architectures (e.g., Figure 28), converting 24 V intermediate bus to tightly regulated 5 V and 12 V outputs. IC Role / Device Role / Timing Role: Fixed-frequency voltage-mode controller managing synchronous rectification and multi-rail feedback via shared compensation node. Use Value: Enables distributed power with <50 mVpp ripple on 5 V rail and <25 mVpp on 12 V rail - confirmed in triple-output test configuration (Figure 25). |
Use Scenario: Powering dual-voltage FPGA core (1.2 V) and I/O (3.3 V) rails in telecom line cards where space and BOM count are constrained. IC Role / Device Role / Timing Role: Step-down regulator operating in continuous conduction mode with external MOSFET drive (Q2 in Figure 21) to extend output current beyond 3 A. Use Value: Supports 0.6 A at 28 V with 82.8% efficiency and ±0.41% line regulation - demonstrated in step-up/down test circuit (Figure 21). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC34166D2TR4G | Same silicon, D2PAK package; 0°C to +70°C temp range; higher thermal resistance (θJA = 70°C/W vs. 65°C/W). | Preferred for surface-mount production; less suitable for high-ambient industrial enclosures above 70°C. | Select when automated assembly and board space are critical, and ambient stays ≤70°C. |
| LM2576T-5.0 | 5 V fixed-output buck regulator; 3.0 A switch; 52 kHz fSW; no inverting capability; requires external diode. | Limited to step-down only; lacks voltage-inverting topology support and integrated current-limit sensing. | Choose for simpler 5 V-only designs where inverting or wide-input flexibility is unnecessary. |
Compared with MC33166TVG, MC34166D2TR4G offers identical functionality in a surface-mount package but sacrifices extended temperature rating and slightly worse thermal performance, while LM2576T-5.0 simplifies design for fixed 5 V step-down but removes configurability for inverting or adjustable outputs.
Availability
MC33166TVG is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power supplies, off-line preconverters, and dual-output telecom systems requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for MC33166TVG 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 (Nasdaq: ON) is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MC33166TVG belongs to onsemi's legacy monolithic switching regulator family, engineered specifically for cost-sensitive, high-reliability DC-DC conversion in step-down and voltage-inverting topologies with minimal external components.
FAQ
What is the maximum recommended input voltage for MC33166TVG?
The absolute maximum input voltage for MC33166TVG is 40 V, as specified in the Maximum Ratings table. Continuous operation above this level risks permanent damage. For reliable long-term use, design margins should keep VCC ≤36 V under worst-case transients - consistent with onsemi's recommended operating conditions and Figure 19 test setup (12 V input, 3 A load).
Can MC33166TVG be used in a step-up (boost) configuration?
MC33166TVG is not designed as a standalone boost regulator. However, onsemi's datasheet explicitly confirms it can be used "cost effectively in step-up applications" when paired with an external power MOSFET (e.g., MTP3055EL in Figure 21), where the IC controls the main switch and the MOSFET handles high-side boosting - achieving 28 V at 0.6 A with 82.8% efficiency.
Does MC33166TVG support voltage-inverting (buck-boost) topologies?
Yes - MC33166TVG is specifically optimized for voltage-inverting configurations, as detailed in Figure 23 and Section 11 of the datasheet. By connecting the IC ground pin to the negative output rail, it regulates −12 V at 1.0 A with 81.2% efficiency and ±0.017% load regulation, resolving emitter swing and reference accessibility constraints inherent to inverting designs.
What is the purpose of Pin 1 (Compensation) on MC33166TVG?
Pin 1 is the error amplifier output and serves two critical functions: (1) it connects to an external RC network (RF, CF) for loop compensation and stability, and (2) clamping its voltage below 0.15 V places MC33166TVG into standby mode, reducing supply current to 36 µA - enabling low-power system states without disabling upstream supplies.
Is MC33166TVG still in active production?
No - per the official onsemi datasheet (Rev. 9, August 2024), MC33166TVG is marked DISCONTINUED and "not recommended for new design." It remains available through authorized distributors for legacy support and repair, but designers should consult onsemi representatives for qualified replacements such as the NCP302 or newer current-mode alternatives.
MC33166TVG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-5 Formed Leads
- Packaging:
- Tube
- Product Status:
- Active
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
MC33166TVG FAQ
1.How can I place an order for MC33166TVG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC33166TVG 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 MC33166TVG reliable?
The price and inventory of MC33166TVG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC33166TVG is usually 5 days.
3.What payment methods are accepted for MC33166TVG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC33166TVG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC33166TVG?
MC33166TVG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC33166TVG 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 MC33166TVG?
For technical support, including MC33166TVG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC33166TVG requirements.
6.How does Aetrix verify that MC33166TVG is sourced from the original manufacturer or authorized distributors?
All MC33166TVG 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 MC33166TVG meets industry standards.
7.What is the process for return or replacement of MC33166TVG?
All MC33166TVG units undergo pre-shipment inspection (PSI). If there is an issue with MC33166TVG, 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 MC33166TVG part is unused and in its original packaging.
Return procedure for MC33166TVG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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