Analog Devices Inc. LTC3221EDC-3.3#TRMPBF

Overview

LTC3221EDC-3.3#TRMPBF from Analog Devices (formerly Linear Technology) is a micropower regulated charge pump DC/DC converter delivering a fixed 3.3V ±4% output from 1.8V–4.4V input, supporting up to 60mA load current with only 8µA no-load quiescent current and no inductors required. It operates in Burst Mode® for ultralow power consumption and integrates short-circuit protection, making it ideal for battery-powered memory backup supplies and tire pressure sensors.

For engineers reviewing the LTC3221EDC-3.3#TRMPBF datasheet, LTC3221EDC-3.3#TRMPBF pinout, LTC3221EDC-3.3#TRMPBF application, or LTC3221EDC-3.3#TRMPBF equivalent, key selection criteria include input voltage range (1.8V–4.4V), regulated 3.3V output tolerance, shutdown current (<1µA), 2mm × 2mm DFN package footprint, and compatibility with ceramic flying capacitors.

Technical Context

The LTC3221EDC-3.3#TRMPBF uses a controlled-current switched-capacitor voltage doubler architecture with hysteresis-based regulation, achieving stable 3.3V output without inductors. Its Burst Mode® operation disables internal circuitry except the comparator when VOUT remains above threshold, minimizing quiescent current at light loads.

It features active short-circuit protection via current-limited ISW delivery (120–240mA typical), shutdown disconnects VOUT from VIN, and employs a 600kHz oscillator with temperature-stable frequency. The device survives indefinite VOUT-to-GND shorts and maintains regulation across –40°C to 85°C operating temperature.

Key Specifications

Pinout & Package

Package: 2mm × 2mm 6-pin DFN (0.75mm height) with exposed thermal pad (Pin 7, GND). Requires soldering of exposed pad to PCB ground plane for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar regulated charge pump applications.

Compared with LTC3221EDC-3.3#TRMPBF, LTC3204EDC-3.3#TRMPBF trades 10× higher quiescent current for 2.5× more output current and larger footprint, while LTC1754EDC-3.3#TRMPBF offers smaller package and lower cost but sacrifices 10mA output headroom and narrower input range.

Availability

LTC3221EDC-3.3#TRMPBF is available at Aetrix Electronics and suitable for memory backup supplies, tire pressure sensors, glucose meters, and low-power RF transmitters requiring stable component supply with long-term lifecycle assurance.

Supply support for LTC3221EDC-3.3#TRMPBF 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

Analog Devices, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC3221 product line was designed specifically for ultra-low-power, inductorless DC/DC conversion in space- and energy-constrained portable and medical electronics.

FAQ

What is the input voltage range supported by the LTC3221EDC-3.3#TRMPBF?

The LTC3221EDC-3.3#TRMPBF supports an input voltage range of 1.8V to 4.4V. This allows direct operation from single-cell lithium-ion, lithium-polymer, or dual-AA/NiMH batteries. Operation below 1.8V is not guaranteed, and exceeding 4.4V risks violating absolute maximum ratings. The device maintains regulation across this full range for loads up to 25mA; at loads up to 60mA, minimum VIN increases to 2.0V.

How does the LTC3221EDC-3.3#TRMPBF achieve such low quiescent current?

The LTC3221EDC-3.3#TRMPBF achieves 8µA typical no-load quiescent current through Burst Mode® operation: the internal oscillator, charge pump switches, and control logic are disabled between regulation events, leaving only the comparator and reference active. This architecture minimizes static power draw while preserving fast transient response-critical for battery longevity in always-on sensor applications using the LTC3221EDC-3.3#TRMPBF.

Can the LTC3221EDC-3.3#TRMPBF survive continuous output short-circuit conditions?

Yes, the LTC3221EDC-3.3#TRMPBF is explicitly rated for indefinite VOUT-to-GND short-circuit duration. Its controlled-current ISW stage inherently limits output current to 120–240mA, preventing thermal damage. During sustained short, the device continues regulating internally while dissipating power safely within its thermal limits-enabling robust operation in fault-prone environments like automotive TPMS where the LTC3221EDC-3.3#TRMPBF is commonly deployed.

What capacitor values and types are required for proper operation of the LTC3221EDC-3.3#TRMPBF?

The LTC3221EDC-3.3#TRMPBF requires three ceramic capacitors: a 1µF X5R/X7R flying capacitor (CFLY) between C+ and C–, a 2.2µF low-ESR ceramic input capacitor (CIN) from VIN to GND, and a 2.2µF (minimum) or 4.7µF (for lowest ripple) ceramic output capacitor (COUT) from VOUT to GND. Polarized capacitors (tantalum, aluminum) are prohibited for CFLY due to voltage reversal risk. All capacitors must be placed close to their respective pins per the recommended layout in the LTC3221EDC-3.3#TRMPBF datasheet.

Is the LTC3221EDC-3.3#TRMPBF pin-compatible with other members of the LTC3221 family?

No-the LTC3221EDC-3.3#TRMPBF is not pin-compatible with the adjustable LTC3221 (which uses Pin 3 as FB instead of SHDN) or the LTC3221EDC-5 (same pinout but different internal feedback network). While all share the same 6-pin DFN package and pin assignments for C+, C–, GND, VIN, and VOUT, the function of Pin 3 differs: SHDN for -3.3/-5 variants versus FB for the adjustable version. Board designs must match the exact variant's control pin functionality.