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onsemi MC33166D2TG
- Part No.:
- MC33166D2TG
- Manufacturer:
- onsemi
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
MC33166D2TG.pdf
- Description:
- IC REG BUCK BST ADJ 3.3A D2PAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:203
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Product details
Overview
MC33166D2TG from onsemi is a fixed-frequency voltage-mode switching regulator IC designed for step-down, voltage-inverting, and step-up/down dc-dc converter applications. It integrates a 72 kHz oscillator, 5.05 V ±2% reference, high-gain error amplifier, latching PWM comparator, and 3.3–6.0 A cycle-by-cycle current-limited NPN output switch. It operates from 7.5 V to 40 V input and delivers up to 3.0 A output in D2PAK-packaged designs for industrial power supplies and automotive auxiliary rails.
For engineers reviewing the MC33166D2TG datasheet, pinout, applications, or equivalent options, key selection considerations include its −40°C to +85°C operating range, internal thermal shutdown, undervoltage lockout with 0.9 V hysteresis, standby mode (36 µA ICC), and compatibility with standard flyback/boost/inverting topologies using external inductors and Schottky rectifiers.
Technical Context
The MC33166D2TG implements voltage-mode control via an internal 5.05 V reference applied to the noninverting input of a high-gain error amplifier; the inverting input accepts feedback from the regulated output. Its fixed 72 kHz oscillator drives a latching PWM comparator that compares the error amp output against a sawtooth ramp, enabling precise duty cycle control from 0% to 95%.
Cycle-by-cycle current limiting monitors switch conduction via an internal sense resistor and comparator, resetting the PWM latch when peak current exceeds 3.3–6.0 A. Undervoltage lockout activates at 5.9 V (with 0.9 V hysteresis) and thermal shutdown engages above 170°C junction temperature - both functions are fully integrated and require no external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 72 kHz nominal; enables stable switching with minimal external timing components (CT only) and supports EMI filtering at predictable frequency. |
| Reference Voltage | 5.05 V ±2% at 25°C; provides accurate regulation setpoint without external divider for 5.0 V outputs, compensating for typical 1% cable drop. |
| Output Switch Current Limit | 3.3 A (min) to 6.0 A (max); protects external NPN transistor during overload while allowing robust 3.0 A continuous output capability. |
| Operating Input Range | 7.5 V to 40 V; supports wide-input industrial and automotive battery-fed systems including 12 V, 24 V, and 36 V rails. |
| Standby Supply Current | 36 µA at 12 V; enables low-power sleep mode by clamping Pin 5 (Comp) below 150 mV, reducing system quiescent consumption. |
| UVLO Threshold | 5.9 V startup / 5.0 V turn-off (0.9 V hysteresis); prevents erratic operation during brown-out and ensures clean power-up sequencing. |
| Junction Temperature Limit | 150°C max operating / 170°C thermal shutdown; defines safe silicon operating envelope and requires heatsinking per D2PAK θJC = 5.0°C/W. |
Pinout & Package
The MC33166D2TG is housed in a Pb-free D2PAK (TO-263) package (Case 936A), with the exposed heatsink tab electrically connected to Pin 3 (GND). This surface-mount package supports high-current thermal dissipation and is rated MSL 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Comp) | Compensation Node | Output of error amplifier; connects to RC network (RF, CF) for loop stability; <150 mV enables standby mode. |
| Pin 2 (VFB) | Voltage Feedback Input | Inverting input of error amp; referenced to internal 5.05 V; used with R1/R2 divider to set output voltage >5.05 V. |
| Pin 3 (GND) | Power & Signal Ground | Common return for internal circuits, switch emitter, and heatsink tab; must be low-impedance connection. |
| Pin 4 (VCC) | Power Supply Input | Primary supply rail (7.5–40 V); powers internal circuitry and oscillator; UVLO monitors this pin. |
| Pin 5 (SW) | Switch Output Collector | Open-collector NPN switch output; drives external transistor base (in inverting/step-up) or collector (in step-down). |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 72 kHz oscillator with on-chip timing | Eliminates external resistor; ensures consistent switching frequency across temperature and supply for predictable EMI filtering. |
| 0% to 95% duty cycle range | Supports wide output voltage ratios in step-down (VOUT < VIN) and inverting (VOUT = −VIN) configurations without external clamp. |
| Internal thermal shutdown at 170°C | Protects die from catastrophic failure under sustained overload or poor heatsinking; auto-recovery after cooldown. |
| Undervoltage lockout with hysteresis | Prevents unstable start-up and oscillation during marginal supply conditions; 0.9 V hysteresis avoids chatter near threshold. |
| 36 µA standby supply current | Enables energy-efficient system-level sleep modes via simple logic-level control of Pin 5, reducing idle power in battery systems. |
Applications
| Industrial Power Supply | Automotive Auxiliary Rail |
|---|---|
Use Scenario: Generating isolated 5.0 V/3.0 A output from 24 V vehicle battery in engine control unit (ECU) power distribution. IC Role / Device Role / Timing Role: Primary controller in step-down topology driving external NPN switch; regulates output via feedback from secondary-side shunt reference. Use Value: Delivers stable 5.0 V at full load with 82.8% efficiency and ±0.05% line regulation, meeting ASIL-B functional safety margin requirements. | Use Scenario: Providing −12 V/1.0 A bias supply for analog sensors and op-amps in ADAS camera modules. IC Role / Device Role / Timing Role: Core controller in voltage-inverting configuration; ground pin tied to negative output to enable proper error amp polarity reversal. Use Value: Achieves −12 V regulation with ±0.017% load regulation and 81.2% efficiency, eliminating need for separate negative charge-pump IC. |
| Triple-Output Distributed PSU | Off-Line Preconverter Stage |
Use Scenario: Generating +5.05 V/2.0 A, +12 V/300 mA, and −12 V/100 mA from 24 V input in programmable logic controller (PLC) backplane. IC Role / Device Role / Timing Role: Master regulator controlling multi-winding transformer primary; auxiliary outputs derived from secondary windings with Volts/Turn ratio tracking. Use Value: Enables single-chip triple-output design with 83.3% total efficiency and cross-regulation within ±1.9%, reducing BOM count vs. discrete regulators. | Use Scenario: Stepping down 115 VAC to 24 VDC in industrial IoT gateway, feeding downstream MC33166D2TG post-regulators. IC Role / Device Role / Timing Role: Post-regulator in off-line preconverter architecture; receives rectified 24 V from self-oscillating flyback stage. Use Value: Provides tightly regulated 24 V output with 90% overall system efficiency and inherent isolation, meeting IEC 61000-4 immunity requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC34166D2TR4G | Same architecture and pinout; rated for 0°C to +70°C ambient (vs. −40°C to +85°C for MC33166D2TG); identical electrical specs. | Suitable for commercial-grade systems without extended temperature requirement; not qualified for automotive or industrial outdoor deployment. | Select MC34166D2TR4G only if ambient operating range is limited to 0–70°C and cost is prioritized over temperature margin. |
| LM2576T-5.0 | Integrated 5.0 V fixed-output buck regulator (vs. adjustable controller); includes internal 3.0 A MOSFET switch; 52 kHz switching; no external NPN required. | Reduces external component count but lacks flexibility for inverting/step-up/down topologies; no compensation pin access. | Choose LM2576T-5.0 for simple 5 V step-down where topology flexibility and temperature range are secondary to BOM simplicity. |
Compared with MC34166D2TR4G, the MC33166D2TG offers extended temperature qualification critical for under-hood automotive use; versus LM2576T-5.0, it trades integration for topology versatility and external switch control - essential for high-efficiency or negative-rail designs.
Availability
MC33166D2TG is available at Aetrix Electronics and suitable for industrial power supplies, automotive auxiliary rails, triple-output distributed PSUs, and off-line preconverter stages requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MC33166D2TG 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 supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MC33166 series belongs to onsemi's legacy analog power controller product line, engineered specifically for cost-sensitive, high-reliability dc-dc converter implementations requiring minimal external components and robust protection features.
FAQ
What is the maximum output current capability of the MC33166D2TG?
The MC33166D2TG itself does not deliver output current directly; it controls an external NPN transistor. Its internal current limit threshold is specified from 3.3 A (min) to 6.0 A (max), enabling reliable 3.0 A continuous output in properly designed step-down or inverting converters. Actual output current depends on external switch selection, heatsinking, and layout - the MC33166D2TG datasheet confirms 3.0 A operation in Figure 19's step-down reference design.
Does the MC33166D2TG support voltage-inverting configurations?
Yes, the MC33166D2TG is explicitly designed for voltage-inverting applications. As shown in Figure 23 of the datasheet, connecting the IC's GND pin (Pin 3) to the negative output rail reverses error amplifier polarity and keeps the switch emitter within its −1.5 V limit. The MC33166D2TG achieves −12 V/1.0 A output with 81.2% efficiency and ±0.017% load regulation in this configuration.
What package type is used for the MC33166D2TG?
The MC33166D2TG uses the D2PAK (TO-263) surface-mount package (Case 936A), with the exposed metal tab electrically connected to Pin 3 (GND). It is Pb-free, moisture sensitivity level (MSL) 1, and rated for 5.0°C/W junction-to-case thermal resistance - confirmed in the "ORDERING INFORMATION" table on page 2 and "MAXIMUM RATINGS" on page 2 of the datasheet.
How does the standby mode function on the MC33166D2TG?
Standby mode on the MC33166D2TG is activated by clamping the Compensation pin (Pin 5) to less than 150 mV, which reduces supply current to 36 µA at 12 V. This low-power state disables the output switch and oscillator while preserving internal reference and UVLO functionality - enabling rapid wake-up. Figure 16 in the datasheet illustrates a simple resistor-divider implementation for controlled entry/exit.
Can the MC33166D2TG be used in step-up (boost) converter designs?
Yes, the MC33166D2TG supports step-up operation, though not as a standalone boost controller. Per the datasheet introduction and Figure 21, it is used in step-up/down configurations with an external power MOSFET (e.g., MTP3055EL) to extend voltage range beyond input. In this arrangement, the MC33166D2TG controls the main switch while the MOSFET handles high-side switching - delivering 28 V/0.6 A with 82.8% efficiency.
MC33166D2TG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tube
- Product Status:
- Last Time Buy
- 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:
- Surface Mount
- Supplier Device Package:
- D2PAK-5
MC33166D2TG FAQ
1.How can I place an order for MC33166D2TG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC33166D2TG 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 MC33166D2TG reliable?
The price and inventory of MC33166D2TG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC33166D2TG is usually 5 days.
3.What payment methods are accepted for MC33166D2TG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC33166D2TG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC33166D2TG?
MC33166D2TG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC33166D2TG 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 MC33166D2TG?
For technical support, including MC33166D2TG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC33166D2TG requirements.
6.How does Aetrix verify that MC33166D2TG is sourced from the original manufacturer or authorized distributors?
All MC33166D2TG 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 MC33166D2TG meets industry standards.
7.What is the process for return or replacement of MC33166D2TG?
All MC33166D2TG units undergo pre-shipment inspection (PSI). If there is an issue with MC33166D2TG, 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 MC33166D2TG part is unused and in its original packaging.
Return procedure for MC33166D2TG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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