STMicroelectronics L6920D

Overview

L6920D from STMicroelectronics is a high-efficiency synchronous step-up DC/DC converter designed for single- to triple-cell battery systems, featuring 0.6V minimum operating input voltage, 1V startup capability, 120mΩ internal N-channel active switch, and fixed/adjustable 3.3V or 5V output (2V–5.2V range). It integrates reverse battery protection, low-battery detection (1.23V threshold), and zero shutdown current (≤1µA), enabling use in portable digital cameras and GPS receivers.

For engineers reviewing the L6920D datasheet, L6920D pinout, L6920D application, or L6920D equivalent, key selection criteria include startup voltage at light load, synchronous rectifier R_DS(on), adjustable feedback topology, and TSSOP8 thermal resistance (250°C/W) for battery-powered PDA and handheld instrument designs.

Technical Context

The L6920D operates using variable-frequency PFM control with maximum on-time (5µs) and minimum off-time (1µs) regulation, enabling high efficiency down to 1V input. Its current-mode architecture enforces 1A peak inductor current limiting and supports discontinuous conduction mode under light loads.

Internal circuitry includes a 1.23V precision reference (±2.5% over temperature), open-drain LBO output with 1.3% hysteresis, and charge-pump gate drive for the N-channel main switch-eliminating external diode requirements while maintaining reverse polarity protection with ≤2µA reverse current at –4V.

Key Specifications

Pinout & Package

TSSOP8 package (4.4mm body width, 0.65mm pitch) with exposed pad not electrically connected; thermal resistance junction-to-ambient = 250°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous boost converter applications.

Compared with TPS61200DRCT and MAX1706EUT+T, the L6920D uniquely combines reverse polarity immunity, programmable low-battery signaling, and 2–5.2V adjustability in TSSOP8-making it optimal for cost-sensitive, battery-reversal-prone handheld instrumentation where external protection adds unacceptable BOM overhead.

Availability

L6920D is available at Aetrix Electronics and suitable for digital cameras, GPS receivers, PDAs, and wireless handheld instruments requiring stable component supply across long-lifecycle portable electronics programs.

Supply support for L6920D 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in power management, analog, and microcontroller solutions for industrial, automotive, and consumer markets.

The L6920D belongs to ST's low-voltage DC/DC converter product line, engineered specifically for energy-constrained portable devices operating from 0.6V–5.5V battery sources with emphasis on startup reliability, reverse protection, and minimal external component count.

FAQ

What is the minimum input voltage required for the L6920D to start switching?

The L6920D guarantees startup at 1V input voltage, verified across temperature and load conditions per datasheet Figure 5. Below 1V, the device remains in inactive state until input rises above this threshold. Once started, it continues regulating down to 0.6V input, making it suitable for deeply discharged single-cell Li-ion or NiMH batteries in portable equipment.

How does the L6920D implement reverse battery protection?

The L6920D incorporates an internal protection circuit that blocks current flow when battery polarity is reversed, limiting reverse current to ≤2µA at –4V input. This prevents damage to both the IC and battery without requiring external FETs or diodes. The protection operates independently of enable state and remains active even in shutdown mode.

Can the L6920D be configured for output voltages other than 3.3V or 5V?

Yes-the L6920D supports adjustable output from 2V to 5.2V using an external resistor divider connected to the FB pin. The output voltage follows V_OUT = 1.23V × (1 + R4/R5), with recommended resistor values between 100kΩ and 10MΩ to minimize error from FB pin bias current (few nA) and ensure stable regulation.

What is the function of the LBO pin and how should it be interfaced?

LBO is an open-drain output that goes low when the scaled battery voltage at LBI falls below 1.23V. It requires an external pull-up resistor (~200kΩ) to V_CC or system logic rail. The output provides hysteresis (1.3%) to prevent oscillation during slow battery decay and can directly drive microcontroller interrupt pins or LED indicators for low-battery warnings.