onsemi CAT6218-270TDGT3

Overview

CAT6218-270TDGT3 from onsemi is a 300 mA CMOS low-dropout linear regulator with 2.70 V fixed output, 180 mV typical dropout at full load, ±1.0% initial output accuracy, and stable operation with only 1 µF ceramic output capacitor. It delivers fast transient response in battery-powered consumer electronics requiring clean, regulated power from 2.3 V to 5.5 V input sources.

For engineers reviewing the CAT6218-270TDGT3 datasheet, pinout, applications, or equivalent options, key selection considerations include guaranteed 300 mA output current, zero shutdown current, quick-start bypass-capacitor support for noise reduction, and thermal protection in the space-constrained TSOT-23-5 package.

Technical Context

The CAT6218-270TDGT3 integrates a CMOS pass transistor with internal voltage reference, fold-back current limiting, and thermal shutdown circuitry. Its enable input features an integrated 2.5 MΩ pull-down resistor, ensuring default-off behavior when left floating.

Operation is optimized for low-noise performance: the BYP pin accepts a 10 nF external capacitor to enhance PSRR above 1 kHz (64 dB at 1 kHz, 54 dB at 20 kHz) and reduce output noise to 45 µV_RMS (10 Hz–100 kHz). Dropout is defined at 2% V_OUT deviation and remains stable across −40°C to +125°C junction temperature.

Key Specifications

Pinout & Package

The CAT6218-270TDGT3 is housed in a RoHS-compliant, lead-free TSOT-23-5 package (Case 419AE), measuring 2.90 mm × 1.60 mm × 1.00 mm max height, with NiPdAu plating and tape-and-reel packaging (3,000 units/reel).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-2702E/TO and TLS850B2TE/V1, the CAT6218-270TDGT3 uniquely balances 300 mA drive capability, ultra-low quiescent current, and configurable noise performance via the BYP pin - making it optimal for space- and noise-sensitive portable electronics where automotive robustness is unnecessary.

Availability

CAT6218-270TDGT3 is available at Aetrix Electronics and suitable for smartphone baseband power, wearable sensor subsystems, and USB-C peripheral hubs requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for CAT6218-270TDGT3 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 innovation for automotive, industrial, cloud, and IoT applications.

The CAT6218 series was designed specifically for battery-powered portable electronics needing high-accuracy, low-noise, low-quiescent LDOs in ultra-thin packages - emphasizing fast transient response and minimal external component count.

FAQ

What is the maximum input voltage rating for the CAT6218-270TDGT3?

The CAT6218-270TDGT3 has an absolute maximum input voltage rating of 6.5 V. However, its recommended operating input range is strictly 2.3 V to 5.5 V. Exceeding 5.5 V may cause permanent damage or violate reliability specifications, even if within the absolute maximum limit. The CAT6218-270TDGT3 must be used within this 2.3–5.5 V window for guaranteed performance and lifetime compliance.

Does the CAT6218-270TDGT3 require an external bypass capacitor to function?

No, the CAT6218-270TDGT3 operates fully functional without the BYP capacitor. The 10 nF capacitor on the BYP pin is optional and serves only to reduce output noise and improve PSRR above 1 kHz. The CAT6218-270TDGT3 delivers stable 2.70 V regulation with just VIN, GND, EN, and VOUT connections and their required 1 µF ceramic capacitors - the BYP cap enhances performance but is not mandatory for basic operation.

What happens to the output of the CAT6218-270TDGT3 when the EN pin is left unconnected?

When the EN pin is left unconnected (floating), the internal 2.5 MΩ pull-down resistor forces the EN node to logic low (<0.4 V), disabling the CAT6218-270TDGT3 output. This ensures fail-safe default-off behavior - the CAT6218-270TDGT3 will not power up unless a valid high-enable signal (≥1.6 V) is actively applied to EN, eliminating risk of unintended activation in open-circuit scenarios.

Can the CAT6218-270TDGT3 safely drive a 300 mA load continuously?

The CAT6218-270TDGT3 guarantees 300 mA output current, but continuous delivery depends on thermal conditions. With a 2.70 V output and minimum 2.3 V input, the worst-case power dissipation is (2.3 V − 2.70 V) × 300 mA = negative - meaning it cannot regulate at 2.3 V input. At VIN = 3.7 V, dissipation is ~300 mW. In a standard TSOT-23-5 on 2-layer FR4, this exceeds safe junction temperature unless board layout provides adequate copper area. The CAT6218-270TDGT3 includes thermal shutdown (160°C) to prevent damage during sustained overload.

Is the CAT6218-270TDGT3 compatible with ceramic output capacitors having ESR below 5 mΩ?

No - the CAT6218-270TDGT3 requires the output capacitor's ESR to be between 5 mΩ and 500 mΩ for guaranteed stability. Ceramic capacitors with ultra-low ESR (e.g., <5 mΩ) can cause oscillation or ringing due to insufficient phase margin in the control loop. To use low-ESR ceramics, a small series resistor (e.g., 5–50 mΩ) must be added to meet the specified ESR range. The CAT6218-270TDGT3 datasheet explicitly defines this requirement and validates stability only within the 5–500 mΩ window.