Texas Instruments LM2682MMX/NOPB

Overview

LM2682MMX/NOPB from Texas Instruments is a CMOS switched-capacitor voltage inverter that converts +2.0V to +5.5V input into −4.0V to −11.0V negative output, delivering up to 10 mA with 90 Ω typical output impedance and 94% power efficiency at 10 mA. It operates at 6 kHz switching frequency and targets low-noise biasing in portable instrumentation and LCD systems.

For engineers reviewing the LM2682MMX/NOPB datasheet, LM2682MMX/NOPB pinout, LM2682MMX/NOPB application, or LM2682MMX/NOPB equivalent, key selection criteria include its VSSOP-8 package, −2×VIN inversion/doubling topology, 150 μA quiescent current, and compatibility with three external 3.3 μF capacitors for inductorless design.

Technical Context

The LM2682MMX/NOPB implements a two-phase charge-pump architecture using four internal MOSFET switches clocked at 6 kHz (f_SW) derived from a 12 kHz oscillator (f_OSC). It requires no inductors and uses external C1, C2, and C3 capacitors to achieve voltage inversion followed by doubling.

Its output regulation relies on fixed-ratio conversion (V_OUT ≈ −2 × V_IN) without feedback control, resulting in load-dependent output impedance (90 Ω typical at 10 mA, 5 V_IN) and ripple governed by C3 ESR and f_OSC. The device supports parallel operation to scale output current and reduce effective ROUT.

Key Specifications

Pinout & Package

VSSOP-8 (DGK) package: 3.0 mm × 3.0 mm body, 0.65 mm pitch, 1.1 mm max height, exposed pad not electrically connected, RoHS-compliant Sn lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switched-capacitor inverter applications.

Compared with MAX680ESA+ and ICL7660SIPAZ, the LM2682MMX/NOPB offers superior package density (VSSOP-8), wider usable input range (2.0–5.5 V), lower output impedance (90 Ω), and higher efficiency (94%), making it optimal for modern portable instrumentation where size and battery life are critical.

Availability

LM2682MMX/NOPB is available at Aetrix Electronics and suitable for LCD contrast biasing, GaAs amplifier biasing, and interface power supplies requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.

Supply support for LM2682MMX/NOPB 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in precision power conversion and signal chain solutions.

The LM2682 product line delivers compact, inductorless voltage inversion for portable and space-constrained applications, targeting designers needing clean, efficient negative rails without magnetics or complex regulation.

FAQ

What is the primary function of the LM2682MMX/NOPB?

The LM2682MMX/NOPB is a switched-capacitor voltage inverter that converts a positive input voltage (2.0 V to 5.5 V) into a corresponding negative output voltage equal to −2×VIN (e.g., −4.0 V to −11.0 V). It achieves this using three external capacitors and no inductor, making it ideal for low-EMI, space-sensitive applications like handheld instrumentation and LCD biasing. The LM2682MMX/NOPB operates at a fixed 6 kHz switching frequency and delivers up to 10 mA with 94% typical efficiency.

Does the LM2682MMX/NOPB require external feedback for regulation?

No, the LM2682MMX/NOPB does not include feedback regulation and provides open-loop −2×VIN conversion. Output voltage accuracy depends on input stability, capacitor ESR, and load current. For regulated outputs, TI recommends adding an external op-amp and reference (e.g., LM358 + LM4040-5.0) as shown in Figure 7 of the LM2682MMX/NOPB datasheet. This configuration maintains ±5% regulation over input variations from 4.5 V to 5.5 V at 9 mA load.

What are the capacitor requirements for the LM2682MMX/NOPB?

The LM2682MMX/NOPB requires three external capacitors: C1 (flying capacitor, ≥6 V rating), C2 (storage capacitor, ≥12 V rating), and C3 (output filter, ≥12 V rating), all typically 3.3 μF low-ESR types. Capacitor selection directly affects output impedance and ripple: larger, lower-ESR capacitors reduce ROUT and VRIPPLE but increase board area. C1 and C2 must handle bidirectional charge transfer; C3 dominates ripple performance per VRIPPLE_P-P = I_OUT × (2×ESR_C3 + 1/[2×f_OSC×C3]).

Can multiple LM2682MMX/NOPB devices be paralleled?

Yes, multiple LM2682MMX/NOPB units can be paralleled to reduce effective output resistance and increase total output current. Each device requires its own C1 and C2 capacitors, but a single shared C3 suffices. Effective ROUT scales inversely with the number of devices (e.g., two units yield ~45 Ω), and maximum output current scales linearly (e.g., two units deliver ~20 mA). Paralleling preserves the same 6 kHz switching frequency and does not require synchronization between units.

What is the thermal and reliability profile of the LM2682MMX/NOPB?

The LM2682MMX/NOPB is rated for −40°C to +85°C ambient operation, with junction temperatures up to +125°C. Its VSSOP-8 package has a θ_J-A of 220°C/W, limiting power dissipation to 300 mW at room temperature. Absolute maximum ratings include +5.8 V VIN, −11.6 V VOUT, and continuous VOUT short-circuit tolerance. ESD protection meets 2 kV HBM and 200 V MM. The LM2682MMX/NOPB is qualified for industrial applications and supported by TI's standard warranty and lifetime product change notifications.