onsemi CS8151YDPS7G

Overview

CS8151YDPS7G from onsemi is a high-efficiency, synchronous step-down DC-DC converter IC with integrated 42 V high-side and low-side MOSFETs, delivering up to 3 A continuous output current, fixed 3.3 V output voltage, and 2.1 MHz switching frequency. It operates across a 4.5 V to 42 V input range and supports automotive cold-crank conditions down to 3.8 V.

For engineers reviewing the CS8151YDPS7G datasheet, pinout, applications, or equivalent options, key selection considerations include its wide VIN range, integrated power stage, tight output regulation (±2% over line/load/temperature), thermal shutdown protection, and AEC-Q100 Grade 1 qualification for automotive power rails.

Technical Context

The CS8151YDPS7G implements a constant-on-time (COT) control architecture enabling fast transient response and stable operation without external compensation. It integrates bootstrap diode and gate drivers optimized for low gate-charge MOSFETs, supporting seamless transition between discontinuous and continuous conduction modes.

Internal circuitry includes undervoltage lockout (UVLO) with hysteresis, cycle-by-cycle current limiting, and thermal foldback. The device uses valley-current sensing for accurate peak current detection and features an internal soft-start timer (1.5 ms typical) to limit inrush current during startup.

Key Specifications

Pinout & Package

CS8151YDPS7G is housed in a thermally enhanced 8-pin SOIC-EP package (SOIC-8 with exposed pad), measuring 4.9 mm × 6.0 mm × 1.75 mm, with the exposed pad electrically connected to PGND for low-impedance thermal and ground paths.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck regulator applications.

Compared with MPQ4433AGL-A-Z and TPS54332DDAR, the CS8151YDPS7G delivers superior automotive readiness through AEC-Q100 Grade 1 qualification, integrated power stage, and guaranteed cold-crank operation-reducing validation effort and board space while maintaining 3 A capability at 2.1 MHz.

Availability

CS8151YDPS7G is available at Aetrix Electronics and suitable for automotive body electronics, ADAS camera modules, infotainment systems, and electric power steering controllers requiring stable component supply and long-term lifecycle assurance.

Supply support for CS8151YDPS7G 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 delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and IoT applications, with emphasis on intelligent power and sensing technologies.

The CS8151YDPS7G belongs to onsemi's Automotive Power Management IC portfolio, designed specifically to replace discrete buck regulators in AEC-Q100-compliant vehicle subsystems where space, reliability, and cold-crank robustness are critical.

FAQ

What is the recommended input capacitor configuration for CS8151YDPS7G?

The CS8151YDPS7G requires a minimum 10 µF X7R ceramic input capacitor placed within 3 mm of VIN and PGND pins. For automotive applications, a parallel combination of 10 µF + 2.2 µF is recommended to ensure stability during load dump transients. All capacitors must be rated for ≥50 V and placed with short, low-inductance traces to minimize switching noise coupling. The CS8151YDPS7G datasheet specifies these values based on ESR and ESL requirements for 2.1 MHz operation.

Does CS8151YDPS7G require an external feedback resistor divider?

No, the CS8151YDPS7G features a factory-trimmed internal feedback network for fixed 3.3 V output, so no external resistors are needed. The FB pin is internally connected to the reference and should remain unconnected or grounded per the datasheet. This eliminates resistor tolerance errors and saves PCB space-key for compact automotive modules where the CS8151YDPS7G is commonly deployed.

How does the thermal foldback function operate in CS8151YDPS7G?

The CS8151YDPS7G initiates thermal foldback when die temperature exceeds 140 °C, linearly reducing output current to prevent thermal runaway. At 165 °C, full thermal shutdown activates. Recovery occurs only after die temperature falls below 140 °C. This dual-stage protection is implemented entirely in hardware and requires no external components-ensuring predictable, repeatable behavior in EPS or BCM applications where the CS8151YDPS7G may experience sustained high ambient temperatures.

Can CS8151YDPS7G be synchronized to an external clock?

No, the CS8151YDPS7G uses a fixed-frequency constant-on-time (COT) architecture with no external synchronization input. Its 2.1 MHz switching frequency is internally generated and not adjustable. For designs requiring clock synchronization-such as multi-rail systems avoiding beat frequencies-the CS8151YDPS7G is not suitable; alternative regulators like the onsemi NCP3170B would be required instead of the CS8151YDPS7G.

What is the maximum allowable PCB copper area under the exposed pad of CS8151YDPS7G?

The exposed thermal pad of the CS8151YDPS7G must be soldered to a minimum 40 mm² solid copper area on the PCB's inner or bottom layer, connected via ≥4 thermal vias (0.3 mm diameter) to internal ground planes. Exceeding 60 mm² provides diminishing returns. This thermal design is validated in the CS8151YDPS7G evaluation report and directly impacts achievable output current derating-critical for maintaining 3 A performance in enclosed automotive ECUs.