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onsemi MC34166D2TR4G
- Part No.:
- MC34166D2TR4G
- Manufacturer:
- onsemi
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
MC34166D2TR4G.pdf
- Description:
- IC REG BUCK BST ADJ 3.3A D2PAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,386
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Product details
Overview
MC34166D2TR4G from onsemi is a fixed-frequency voltage-mode switching regulator IC optimized for step-down, voltage-inverting, and step-up/down DC-DC converter topologies. It integrates a 3.0 A output switch, 72 kHz oscillator, precision 5.05 V ±2% reference, error amplifier, PWM latch, cycle-by-cycle current limiting, undervoltage lockout (5.9 V startup), and thermal shutdown. It operates from 7.5 V to 40 V input and delivers regulated outputs in automotive power supplies, industrial SMPS, and embedded DC-DC modules.
For engineers reviewing the MC34166D2TR4G datasheet, pinout, applications, or equivalent options, key selection considerations include its D2PAK surface-mount package, 0–95% duty cycle control, 36 µA standby current, internal current limit threshold of 4.3 A (typ), and compatibility with Schottky rectifiers in flyback-derived configurations.
Technical Context
The MC34166D2TR4G implements voltage-mode PWM control using an internal 72 kHz oscillator with fixed charge/discharge thresholds (4.1 V / 2.3 V) and a latching comparator that prevents multiple pulses per cycle. Its error amplifier features 80 dB open-loop gain and 600 kHz unity-gain bandwidth, with the noninverting input tied internally to the 5.05 V reference - no external feedback divider required for 5.0 V output.
Cycle-by-cycle current limiting monitors switch conduction via an internal sense resistor and comparator, resetting the PWM latch when peak current reaches 4.3 A (typ). Undervoltage lockout provides 5.9 V startup with 0.9 V hysteresis, while thermal shutdown activates at ~170 °C to disable the output stage - not intended as a substitute for heatsinking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 72 kHz (fixed, internally trimmed; enables predictable EMI filtering and stable loop design) |
| Reference Voltage | 5.05 V ±2% (internal; eliminates need for external resistor divider in 5.0 V output designs) |
| Output Switch Current | 3.0 A continuous (supports up to 3.0 A load in step-down configuration without external MOSFET) |
| Duty Cycle Range | 0% to 95% (enables wide input-to-output voltage ratio coverage in inverting and step-up/down topologies) |
| Input Voltage Range | 7.5 V to 40 V (supports 12 V/24 V automotive and industrial bus inputs with margin) |
| Standby Supply Current | 36 µA at 12 V (achieved by clamping Pin 5 < 150 mV; reduces system quiescent power significantly) |
| Current Limit Threshold | 4.3 A typical (cycle-by-cycle protection; prevents switch overstress during overload or short-circuit) |
Pinout & Package
The MC34166D2TR4G is housed in a Pb-free D2PAK (TO-263) surface-mount package (Case 936A), with the exposed tab thermally and electrically connected to Pin 3 (Ground). This package offers 5.0 °C/W junction-to-case thermal resistance and MSL Level 1 moisture sensitivity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Compensation) | Error amplifier output / compensation node | Connects to RC network (RF, CF) for loop stability; also used for soft-start via 100 µA pull-up current source |
| Pin 2 (Switch Output) | Collector of internal NPN power transistor | Drives external inductor; must be paired with Schottky rectifier (e.g., 1N5822); emitter swing limited to −1.5 V relative to GND |
| Pin 3 (Ground) | Power and signal ground reference | Common return for internal circuits; tab connection point; must be low-impedance PCB plane for thermal and noise control |
| Pin 4 (VCC) | Primary power supply input | Accepts 7.5–40 V; powers all internal blocks; UVLO monitors this pin for startup and shutdown |
| Pin 5 (Feedback) | Inverting input of error amplifier | Connected to output divider; threshold = 5.05 V; clamping below 150 mV enables 36 µA standby mode |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3.0 A NPN switch | Eliminates need for external high-current transistor in step-down converters up to ~3 A output |
| Fixed 72 kHz oscillator with on-chip timing | Removes external timing capacitor; simplifies BOM and improves frequency stability over temperature |
| 5.05 V ±2% internal reference | Enables accurate 5.0 V regulation without external resistors; compensates for typical 1% cable drop |
| Cycle-by-cycle current limiting | Provides immediate overcurrent protection per switching cycle - critical for reliability in transient-loaded systems |
| Undervoltage lockout with hysteresis | Ensures clean startup above 5.9 V and prevents oscillation near threshold via 0.9 V hysteresis band |
| Thermal shutdown at ~170 °C | Protects die from catastrophic failure due to inadequate heatsinking or sustained overload |
Applications
| Automotive Body Control Module Power | Industrial Sensor Signal Conditioning Supply |
|---|---|
Use Scenario: Generating isolated 5.0 V rail from 12 V battery for microcontroller, CAN transceiver, and analog sensors in BCM. IC Role / Device Role / Timing Role: Step-down regulator controlling duty cycle to maintain 5.0 V output under cold-crank (6.5 V) and load-dump (36 V) conditions. Use Value: Internal 5.05 V reference and 72 kHz oscillator ensure stable regulation without external trimming; 36 µA standby current extends battery life during sleep mode. |
Use Scenario: Providing clean, low-noise −12 V bias for op-amps and ADC drivers in factory-floor sensor nodes. IC Role / Device Role / Timing Role: Voltage-inverting regulator using MC34166D2TR4G in topology shown in Figure 23, with ground referenced to negative output. Use Value: 0–95% duty cycle and internal current limiting enable reliable inversion from 12 V to −12 V/1.0 A; Schottky rectifier support minimizes conduction loss. |
| Off-Line AC-DC Preconverter Stage | Brushed DC Motor Speed Controller |
Use Scenario: Secondary-side post-regulator in 125 W offline SMPS (Figure 28), delivering precise 24 V from transformer-derived 36 V intermediate bus. IC Role / Device Role / Timing Role: Step-down controller regulating output under variable line and load; coordinated with primary-side self-oscillating flyback. Use Value: Fixed 72 kHz frequency allows predictable EMI filter design; 4.3 A current limit protects against transformer saturation faults. |
Use Scenario: Variable-speed drive for 18 V brushed motor in portable test equipment, using back-EMF sensing for closed-loop RPM control. IC Role / Device Role / Timing Role: PWM generator modulating switch duty cycle based on EMF feedback; internal oscillator sets base frequency. Use Value: 0–95% controllable duty cycle enables full 0–100% speed range; integrated current limit prevents stall damage during startup. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC33166D2TR4G | Wider operating ambient range (−40°C to +85°C) vs. MC34166D2TR4G (0°C to +70°C); identical electrical specs and pinout | Suitable for extended-temperature industrial or automotive under-hood use where ambient exceeds 70°C | Select MC33166D2TR4G when operation beyond +70°C is required; otherwise MC34166D2TR4G offers cost advantage |
| LM2576T-5.0 | 5.0 V fixed-output buck regulator; 3.0 A switch; 52 kHz frequency; requires external diode and inductor; no inverting capability | Limited to step-down only; lacks voltage-inverting and step-up/down flexibility of MC34166D2TR4G | Choose LM2576T-5.0 for simpler 5.0 V step-down designs where topology flexibility is unnecessary |
Compared with MC33166D2TR4G, the MC34166D2TR4G trades extended temperature rating for lower cost in commercial-grade applications; compared with LM2576T-5.0, it offers broader topology support (inverting, step-up/down) and higher oscillator frequency for smaller magnetics - at the expense of requiring external feedback configuration for non-5V outputs.
Availability
MC34166D2TR4G is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor power supplies, off-line preconverters, and brushed motor controllers requiring stable component supply across production lifecycles.
Supply support for MC34166D2TR4G 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 supplier specializing in energy-efficient silicon solutions for automotive, industrial, cloud, and IoT applications.
The MC34166 series belongs to onsemi's legacy power management IC portfolio, designed specifically for cost-sensitive, fixed-frequency DC-DC converter implementations requiring minimal external components in step-down, inverting, and step-up/down topologies.
FAQ
What is the maximum input voltage rating for the MC34166D2TR4G?
The MC34166D2TR4G has an absolute maximum power supply input voltage (VCC) of 40 V, as specified in the Maximum Ratings table. Operation above this level risks permanent device damage. For reliable long-term use, the recommended operating range is 7.5 V to 40 V, with derating advised near the upper limit depending on thermal conditions and duty cycle.
Does the MC34166D2TR4G require an external feedback resistor divider to regulate 5.0 V output?
No - the MC34166D2TR4G includes an internal 5.05 V ±2% reference connected to the noninverting input of the error amplifier. When Pin 5 (Feedback) is connected directly to the regulated output, the device delivers 5.05 V; for exactly 5.0 V, minor cable-drop compensation is inherent, and no external divider is needed. A divider is only required for output voltages >5.05 V.
How does the standby mode function in the MC34166D2TR4G?
Standby mode in the MC34166D2TR4G is activated by clamping Pin 1 (Compensation) to <150 mV, which disables internal circuitry and reduces supply current to 36 µA at 12 V. This is implemented externally using a transistor or logic-level signal. The mode preserves regulation capability and allows fast wake-up - essential for battery-powered systems needing ultra-low quiescent power.
Can the MC34166D2TR4G be used in a voltage-inverting configuration?
Yes - the MC34166D2TR4G is explicitly designed for voltage-inverting applications, as confirmed in the datasheet title and Figure 23. It achieves this by referencing the IC ground (Pin 3) to the negative output rail, reversing error amplifier polarity. The internal 5.05 V reference and 0–95% duty cycle support stable −12 V/1.0 A output with proper Schottky rectification and layout.
What package type and thermal characteristics apply to the MC34166D2TR4G?
The MC34166D2TR4G uses the D2PAK (TO-263) surface-mount package (Case 936A), with the exposed metal tab electrically and thermally connected to Pin 3 (Ground). Its junction-to-case thermal resistance is 5.0 °C/W, and junction-to-ambient is 70 °C/W at TA = +25°C on a standard PCB. MSL rating is Level 1, permitting unlimited floor life before reflow.
MC34166D2TR4G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tape & Reel (TR)
- 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- D2PAK-5
MC34166D2TR4G FAQ
1.How can I place an order for MC34166D2TR4G through Aetrix?
Please submit a Request for Quotation (RFQ) for MC34166D2TR4G 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 MC34166D2TR4G reliable?
The price and inventory of MC34166D2TR4G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC34166D2TR4G is usually 5 days.
3.What payment methods are accepted for MC34166D2TR4G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC34166D2TR4G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC34166D2TR4G?
MC34166D2TR4G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC34166D2TR4G 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 MC34166D2TR4G?
For technical support, including MC34166D2TR4G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC34166D2TR4G requirements.
6.How does Aetrix verify that MC34166D2TR4G is sourced from the original manufacturer or authorized distributors?
All MC34166D2TR4G 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 MC34166D2TR4G meets industry standards.
7.What is the process for return or replacement of MC34166D2TR4G?
All MC34166D2TR4G units undergo pre-shipment inspection (PSI). If there is an issue with MC34166D2TR4G, 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 MC34166D2TR4G part is unused and in its original packaging.
Return procedure for MC34166D2TR4G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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