onsemi NCV8135BMT040TBG

Overview

NCV8135BMT040TBG from onsemi is a 500 mA very low dropout (VLDO) CMOS voltage regulator with NMOS pass transistor and separate VBIAS rail, delivering 0.4 V fixed output at ±1% accuracy over temperature, 53 mV typical dropout at full load, and 35 µA typical bias quiescent current - designed for noise-sensitive, space-constrained automotive point-of-load regulation.

For engineers reviewing the NCV8135BMT040TBG datasheet, pinout, applications, or equivalent options, this page provides verified technical context, WDFN6 package mapping, real-world load transient behavior, PSRR performance at 1 kHz, and validated alternative options for 0.4 V automotive LDO designs.

Technical Context

The NCV8135BMT040TBG uses an NMOS pass transistor architecture powered by dual rails: VIN supplies the output path, while VBIAS independently powers internal control circuitry - enabling ultra-low dropout (53 mV @ 500 mA) and high PSRR (90 dB from VBIAS at 1 kHz). Its enable input features built-in hysteresis and supports monotonic soft-start.

This variant lacks active output discharge (distinguishing it from NCV8135A versions), operates across −40°C to +125°C, and is AEC-Q100 qualified. It achieves stable regulation with only a 10 µF ceramic output capacitor and tolerates input as low as 0.4 V - critical for modern low-voltage SoC core rails.

Key Specifications

Pinout & Package

NCV8135BMT040TBG is housed in a thermally enhanced WDFN6 2 mm × 2 mm package (Case 511BR) with wettable flanks option available; the exposed thermal pad must be soldered to PCB ground plane for optimal thermal performance (R_JA = 97°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-voltage LDO applications.

Compared with NCV8135BMT040TBG, the NCV8135AMT040TBG adds discharge functionality without altering regulation performance, while the TLD1120FV sacrifices dropout and PSRR for integration simplicity - making NCV8135BMT040TBG optimal for noise-critical, ultra-low-headroom automotive loads.

Availability

NCV8135BMT040TBG is available at Aetrix Electronics and suitable for automotive camera modules, LPDDR4 I/O regulation, and always-on vehicle network nodes requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for NCV8135BMT040TBG 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 focused on energy-efficient electronics for automotive, industrial, cloud, and IoT applications.

The NCV8135 series belongs to onsemi's automotive-qualified power management portfolio, engineered specifically for ultra-low-voltage, high-accuracy point-of-load regulation in safety-critical vehicle subsystems.

FAQ

What is the key functional difference between NCV8135BMT040TBG and NCV8135AMT040TBG?

The NCV8135BMT040TBG omits the active output discharge feature present in the NCV8135AMT040TBG. When disabled, NCV8135BMT040TBG allows VOUT to decay naturally through load leakage, whereas NCV8135AMT040TBG actively pulls VOUT to GND via a 150 Ω internal FET. All other electrical specifications, pinout, and package are identical for both NCV8135BMT040TBG and NCV8135AMT040TBG.

Does NCV8135BMT040TBG require an external capacitor on the VBIAS pin?

Yes, NCV8135BMT040TBG requires a minimum 0.1 µF ceramic capacitor between VBIAS and GND, placed as close as possible to the pin. This stabilizes the internal control circuitry supply and prevents oscillation during fast load transients. The datasheet specifies C_BIAS ≥ 0.1 µF for reliable operation of NCV8135BMT040TBG across its full temperature and load range.

Can NCV8135BMT040TBG operate with VIN = 0.4 V and deliver 500 mA?

No - NCV8135BMT040TBG requires VIN ≥ VOUT + V_DO. With VOUT = 0.4 V and typical dropout of 53 mV, minimum VIN is 0.453 V. At exactly 0.4 V input, NCV8135BMT040TBG cannot regulate and will enter dropout, causing VOUT to fall below specification. Valid operation starts at VIN ≥ 0.453 V for full 500 mA load.

Is the SNS pin mandatory for proper operation of NCV8135BMT040TBG?

Yes, the SNS pin must be connected directly to the VOUT net at the load point for accurate regulation. Leaving SNS unconnected or tying it to the IC's VOUT pin defeats remote sensing and degrades load regulation to ±0.5 mV (vs. ±0.1 mV with proper SNS routing). This requirement applies to all NCV8135BMT040TBG installations demanding tight output tolerance.

What thermal derating applies to NCV8135BMT040TBG at 125°C ambient?

At 125°C ambient, NCV8135BMT040TBG's maximum continuous output current is limited by junction temperature. With R_JA = 97°C/W and T_J(MAX) = 125°C, power dissipation must stay below 0 W - meaning NCV8135BMT040TBG cannot sustain any load at 125°C ambient without additional heatsinking. Derating begins above 85°C ambient; consult Figure 3 in the datasheet for exact I_OUT vs. T_A curves for NCV8135BMT040TBG.