Texas Instruments LM828M5X/NOPB

Overview

LM828M5X/NOPB from Texas Instruments is a CMOS switched-capacitor voltage inverter IC that converts +1.8V to +5.5V input into corresponding −1.8V to −5.5V output, delivering up to 25 mA with 20 Ω typical output impedance and 97% conversion efficiency at 5 mA load. It operates at 12 kHz switching frequency and draws only 40 µA quiescent current, making it ideal for low-power portable systems requiring dual-rail analog supplies.

For engineers reviewing the LM828M5X/NOPB datasheet, LM828M5X/NOPB pinout, LM828M5X/NOPB application, or LM828M5X/NOPB equivalent, key selection criteria include its SOT-23-5 package footprint, inverting topology without inductors, low-noise charge-pump architecture, and compatibility with ceramic or low-ESR tantalum capacitors for handheld instrumentation and op-amp biasing.

Technical Context

The LM828M5X/NOPB implements a four-switch CMOS charge-pump topology that alternately charges and transfers energy between two external capacitors to invert polarity. Its internal oscillator runs at 12 kHz (typ), driving switches at half that frequency (6 kHz at CAP+), minimizing output ripple while enabling compact external component selection.

Output regulation is unregulated by design - the unloaded output approximates −V_IN, with voltage drop under load determined by internal MOSFET R_DS(on), capacitor ESR, and switching frequency. The device supports cascading for deeper inversion (e.g., −2×V_IN) and paralleling to reduce effective output resistance.

Key Specifications

Pinout & Package

LM828M5X/NOPB is housed in a 5-pin SOT-23 (DBV) package, 2.9 mm × 1.6 mm × 1.45 mm, with gull-wing leads and RoHS-compliant matte tin lead finish (SN). Pin 1 is marked with a dot or notch; orientation follows JEDEC MO-178 standard with Q2 quadrant assignment on tape.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage inverter applications.

Compared with MAX680ESA+ and ICL7660SIPAZ, LM828M5X/NOPB offers superior current drive (25 mA), lowest quiescent current (40 µA), and smallest footprint (SOT-23-5), making it optimal for high-density, battery-sensitive applications where moderate ripple is acceptable.

Availability

LM828M5X/NOPB is available at Aetrix Electronics and suitable for cellular phones, handheld instruments, operational amplifier power supplies, interface power supplies, and PDAs requiring stable component supply across production lifecycles.

Supply support for LM828M5X/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 logic technologies, with decades of expertise in power management and precision analog solutions.

The LM828M5X/NOPB belongs to TI's legacy linear power conversion portfolio, designed specifically for low-noise, inductor-free negative voltage generation in portable and space-constrained electronic systems.

FAQ

What is the maximum continuous output current specification for LM828M5X/NOPB?

The LM828M5X/NOPB supports up to 25 mA of continuous output current under typical conditions (T_A = 25°C, V_IN = 5V). Absolute maximum rating allows 50 mA, but sustained operation above 25 mA increases output impedance effects and thermal stress. Derating is recommended above 85°C ambient per the datasheet's thermal resistance (θ_JA = 300°C/W).

Does LM828M5X/NOPB require external regulation to maintain stable output voltage?

No - LM828M5X/NOPB is an unregulated charge-pump inverter. Its output voltage approximates −V_IN under no load, but drops linearly with load current due to output impedance (~20 Ω typ). For regulated outputs, TI recommends cascading with an LDO like LP2980, as documented in Figure 16 of the LM828M5X/NOPB datasheet.

Which capacitor types are validated for use with LM828M5X/NOPB?

TI validates ceramic, low-ESR tantalum (e.g., AVX TPS, Sprague 593D), and aluminum electrolytic (e.g., Nichicon PL/PF) capacitors for LM828M5X/NOPB. The datasheet specifies 10 µF/0.3Ω max ESR for C1 and C2; ceramic chips are preferred for lowest ripple and smallest footprint in LM828M5X/NOPB designs.

Can multiple LM828M5X/NOPB devices be paralleled to increase output current capability?

Yes - the LM828M5X/NOPB supports paralleling to reduce effective output resistance. Each unit requires its own C1 pumping capacitor, while a shared C2 output capacitor suffices. Per Equation (4) in the LM828M5X/NOPB datasheet, composite R_OUT = R_{OUT_1}/n for n identical devices, enabling up to ~100 mA with four units.

What is the operating temperature range for LM828M5X/NOPB, and how does it affect performance?

The LM828M5X/NOPB is rated for −40°C to +85°C junction temperature. At extremes, oscillator frequency shifts (±20% over range), output impedance rises ~2× at −40°C, and efficiency drops ~3% at +85°C. Short-circuit protection is disabled above 85°C; full derating is required per the absolute maximum ratings table in the LM828M5X/NOPB datasheet.