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onsemi NCV8851DBG
- Part No.:
- NCV8851DBG
- Manufacturer:
- onsemi
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
NCV8851DBG.pdf
- Description:
- IC REG DL BUCK/LNR SYNC 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,700
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Product details
Overview
NCV8851DBG from onsemi is an automotive-grade synchronous buck controller with average current mode control, driving dual N-channel MOSFETs for high-current DC-DC conversion. It operates from 4.5 V to 20 V input, delivers adjustable output down to 0.8 V ±2%, integrates a 6.0 V LDO, and supports programmable switching frequency from 170 kHz to 500 kHz - used in engine control units and ADAS power rails.
For engineers reviewing the NCV8851DBG datasheet, pinout, applications, or equivalent options, key selection considerations include its 1.5 A gate drivers, adaptive non-overlap timing (≤70 ns delay), cycle-by-cycle OCP threshold of 115–215 mV, thermal shutdown at 150–210 °C, and TSSOP-20 Pb-free package compatibility with automotive thermal and EMI constraints.
Technical Context
The NCV8851DBG implements average current mode control (ACMC) using dual error amplifiers: a voltage error amplifier (VEA) with 70–73 dB DC gain and 8–10 MHz GBW, and a current error amplifier (CEA) with identical gain-bandwidth specs. The inner current loop senses inductor current via CSP/CSN differential inputs (1.2–10 V common-mode range, unity gain), while the outer voltage loop regulates output via VFB referenced to 0.784–0.816 V.
It features a fixed-frequency oscillator with ROSC-programmable range (170–500 kHz), external SYNC capability up to 600 kHz, and integrated protection including undervoltage lockout (4.1–4.5 V on VIN_IC), thermal shutdown (150–210 °C), and adaptive non-overlap circuitry ensuring ≥150 ns minimum GH off-time and ≤70 ns GH/GL propagation delays.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 20 V - supports full automotive battery range including cold-crank (≥4.5 V) and load-dump transients (up to 45 V peak on EN/VIN). |
| Reference Voltage | 0.8 V ±2% - enables precise output regulation from 0.8 V upward using external resistor divider; critical for low-voltage microcontroller core supplies. |
| Switching Frequency | 170–500 kHz (ROSC-programmed); up to 600 kHz (SYNC) - balances inductor size vs. switching loss; avoids AM band interference in vehicle systems. |
| LDO Output | 6.0 V ±3.3% at 20 mA - powers internal logic and low-side gate driver; dropout ≤200 mV ensures stable operation during input sag. |
| Gate Drive Current | 1.5 A sink/source per GH/GL - drives high-Qg MOSFETs for >10 A output designs without external buffers; reduces conduction loss and layout complexity. |
| Current Limit Threshold | Average: 80–125 mV; Cycle-by-cycle: 115–215 mV - sets overcurrent protection level directly via sense resistor; enables fast fault response without latch-off. |
| Quiescent Current | ≤1 µA in sleep mode (EN = 0 V); 3.2–5.0 mA active - meets automotive "always-on" module requirements for low standby power consumption. |
Pinout & Package
TSSOP-20 (Pb-free, Case 948E), thermally enhanced with exposed pad; 0.65 mm pitch; 6.5 mm × 4.4 mm footprint. Designed for automotive PCB layouts requiring high thermal dissipation and EMI resilience.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SYNC) | External clock input | TTL-compatible sync input; rising edge initiates new switching cycle; supports daisy-chained multi-phase systems up to 600 kHz. |
| 4 (BST) | Bootstrap supply input | Connects to external diode + 0.1 µF capacitor from 6VOUT → BST; generates floating 6 V rail for high-side NMOS gate drive. |
| 5 (GH) | High-side gate driver output | 1.5 A source/sink driver for external NMOS; includes adaptive non-overlap to prevent shoot-through; min off-time = 150 ns. |
| 6 (VSW) | Switch node | Connects to source of high-side FET and drain of low-side FET; requires 4300 pF snubber to ground for EMI suppression. |
| 7 (GL) | Low-side gate driver output | 1.5 A source/sink driver; referenced to PGND; complements GH for synchronous rectification; matched delay ≤70 ns. |
| 9 (6VOUT) | LDO output | 6.0 V regulated supply; powers VIN_IC and low-side driver; requires ≥1 µF ceramic bypass to AGND for noise immunity. |
| 11 (EN) | Enable input | TTL-compatible enable; <0.8 V disables IC into 1 µA sleep mode; >2.0 V enables soft-start and LDO; supports VIN tie-high with REN. |
| 12 (VIN) | Main SMPS input | Primary power input (4.5–20 V); feeds high-current path; must be decoupled near PGND with low-ESR bulk capacitor. |
| 13 (VFB) | Voltage feedback input | Inverting input to VEA; connects to resistive divider from VOUT; sets output voltage as VOUT = 0.8 V × (1 + R1/R2). |
| 19 (CSP) | Current sense + input | Non-inverting input to CSA; measures inductor current via series sense resistor; common-mode range 1.2–10 V. |
Key Features
| Feature | Design Value |
|---|---|
| Average current mode control (ACMC) | Enables Type-II compensation only - simplifies loop stability design and delivers faster load transient response than voltage-mode controllers. |
| Adaptive non-overlap circuitry | Guarantees ≥150 ns minimum GH off-time and ≤70 ns GH/GL propagation mismatch - eliminates shoot-through risk across temperature and process variation. |
| Programmable fixed-frequency oscillator | ROSC resistor sets frequency from 170–500 kHz; allows optimization of inductor size, efficiency, and EMI profile per application. |
| Dual overcurrent protection | Average current limiting (ACL) + cycle-by-cycle OCP - provides graceful current foldback under overload and immediate shutdown during short-circuit. |
| Automotive thermal robustness | Thermal shutdown at 150–210 °C with 10–20 °C hysteresis - protects die during sustained high-power operation in under-hood environments. |
Applications
| Engine Control Unit (ECU) Power Supply | ADAS Camera Module Rail |
|---|---|
|
Use Scenario: Supplies 1.2 V @ 8 A to MCU and CAN transceivers in gasoline/diesel engine control modules operating at −40 °C to +125 °C ambient. IC Role / Device Role / Timing Role: Primary synchronous buck controller regulating main domain supply; manages dynamic load steps during ignition pulses and sensor sampling bursts. Use Value: 0.8 V reference tolerance and ACMC ensure <±1% output regulation across wide input (6–16 V) and load (0–8 A); LDO powers gate drivers without external bias rail. |
Use Scenario: Generates 3.3 V @ 3 A for image signal processor and MIPI interface in forward-facing radar/camera fusion units. IC Role / Device Role / Timing Role: High-efficiency pre-regulator feeding downstream LDOs; synchronized to system clock via SYNC pin to reduce spectral noise peaks. Use Value: 500 kHz max switching frequency enables compact 2.2 µH inductor; 1.5 A gate drivers support low-Rds(on) MOSFETs for >92% efficiency at full load. |
| Infotainment System Core Rail | Electric Power Steering (EPS) Sensor Bias |
|
Use Scenario: Delivers 1.1 V @ 12 A to application processor SoC in head-unit systems with aggressive thermal constraints. IC Role / Device Role / Timing Role: High-current buck controller with soft-start and ACL limiting inrush during cold boot and firmware updates. Use Value: Internal soft-start (14 ms at 170 kHz) prevents input voltage droop; average current limit avoids pulse-skipping instability during CPU burst loads. |
Use Scenario: Provides isolated 5.0 V @ 150 mA bias to torque and position sensors in EPS motor control modules. IC Role / Device Role / Timing Role: Pre-regulated supply for precision analog front-ends; UVLO (4.1–4.5 V) prevents erratic behavior during battery brownouts. Use Value: 6.0 V LDO output powers sensor excitation circuits; tight 0.8 V reference enables accurate calibration of downstream ADC references. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5116QPWPRQ1 | Current-mode (not average current mode); no integrated 6 V LDO; requires external bias supply for gate drivers. | Better suited for ultra-high input (>60 V) industrial DC-DC; lacks automotive qualification for junction temp >150 °C. | Select when higher Vin range or external driver flexibility is needed; avoid if 6 V LDO integration or ACMC transient performance is required. |
| MPQ4312-AEC1 | Integrated power stage (MOSFETs included); fixed 500 kHz frequency; no ROSC/SYNC programmability. | Targeted at space-constrained infotainment displays; not configurable for variable-frequency EMI tuning. | Choose for simplified BOM and layout where 12 A integrated solution suffices; not suitable for discrete high-power (>20 A) designs requiring N-channel FETs. |
Compared with LM5116QPWPRQ1 and MPQ4312-AEC1, the NCV8851DBG uniquely combines automotive-grade average current mode control, integrated 6 V LDO for self-contained gate drive, and ROSC/SYNC frequency flexibility - making it optimal for high-reliability, thermally demanding, and EMI-sensitive vehicle subsystems.
Availability
NCV8851DBG is available at Aetrix Electronics and suitable for automotive engine control, ADAS camera modules, and infotainment power supplies requiring stable component supply across extended temperature and long lifecycle commitments.
Supply support for NCV8851DBG 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 is a global semiconductor leader focused on energy-efficient innovation, delivering silicon solutions for automotive, industrial, cloud, and IoT applications with strong automotive AEC-Q100 qualification infrastructure.
The NCV8851DBG belongs to onsemi's automotive power management IC portfolio, designed specifically for high-current, high-reliability DC-DC conversion in under-hood and safety-critical vehicle systems.
FAQ
What is the maximum duty cycle supported by the NCV8851DBG at 500 kHz?
The NCV8851DBG supports up to 89% maximum duty cycle at 500 kHz, limited by its minimum off-time of 150 ns to ensure reliable bootstrap capacitor recharge. At lower frequencies (e.g., 200 kHz), duty cycle extends to ≥95%. This constraint is critical when designing for low-Vin/high-Vout ratios such as 6 V input to 5 V output in start-stop automotive systems - the NCV8851DBG maintains regulation without dropout.
How does the NCV8851DBG implement cycle-by-cycle overcurrent protection?
The NCV8851DBG uses a dedicated fast OCP path comparing CSP–CSN differential voltage against a 115–215 mV threshold. When exceeded, the PWM pulse terminates within ≤200 ns and switching halts until inductor current falls below the threshold. Unlike latch-off schemes, the NCV8851DBG resumes normal operation on the next cycle - enabling robust short-circuit handling in motor driver pre-regulators without system reset.
Can the NCV8851DBG operate without an external bootstrap diode?
No - the NCV8851DBG requires an external Schottky diode (e.g., NSR0330HT1G) from 6VOUT to BST to charge the BST capacitor during low-side conduction. Omitting this diode prevents high-side gate drive voltage generation, causing GH to remain inactive and forcing single-ended operation. The diode must support ≥1 A peak reverse recovery current and ≤0.4 V forward drop for reliable startup across temperature.
What is the purpose of the 4300 pF snubber on the VSW pin of the NCV8851DBG?
The 4300 pF ceramic capacitor + 1 Ω resistor snubber on VSW suppresses high-frequency ringing caused by parasitic inductance in the power loop, reducing EMI emissions and preventing false triggering of the current sense amplifier. It is mandatory per onsemi design guidelines - omission risks erratic current limiting, gate driver instability, and failure to meet CISPR-25 Class 5 automotive EMI limits.
Does the NCV8851DBG require external compensation components for both control loops?
Yes - the NCV8851DBG requires separate Type-II compensation networks for the voltage error amplifier (VEA, pins VFB/VCOMP/CCOMP) and current error amplifier (CEA, pins CFB/CSOUT/CCOMP). Each uses one resistor and two capacitors; values depend on selected inductor, output capacitor ESR, and switching frequency. onsemi Application Note AND8387/D provides exact design equations and stability criteria for both loops.
NCV8851DBG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Topology:
- Step-Down (Buck) Synchronous (1), Linear (LDO) (1)
- Number of Outputs:
- 2
- Frequency - Switching:
- 170kHz ~ 500kHz
- Voltage/Current - Output 1:
- Controller
- Voltage/Current - Output 2:
- 6V, 30mA
- Voltage/Current - Output 3:
- -
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- Yes
- Voltage - Supply:
- 4.5V ~ 20V
- Operating Temperature:
- -40°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
NCV8851DBG FAQ
1.How can I place an order for NCV8851DBG through Aetrix?
Please submit a Request for Quotation (RFQ) for NCV8851DBG 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 NCV8851DBG reliable?
The price and inventory of NCV8851DBG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCV8851DBG is usually 5 days.
3.What payment methods are accepted for NCV8851DBG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCV8851DBG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCV8851DBG?
NCV8851DBG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCV8851DBG 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 NCV8851DBG?
For technical support, including NCV8851DBG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCV8851DBG requirements.
6.How does Aetrix verify that NCV8851DBG is sourced from the original manufacturer or authorized distributors?
All NCV8851DBG 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 NCV8851DBG meets industry standards.
7.What is the process for return or replacement of NCV8851DBG?
All NCV8851DBG units undergo pre-shipment inspection (PSI). If there is an issue with NCV8851DBG, 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 NCV8851DBG part is unused and in its original packaging.
Return procedure for NCV8851DBG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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