CN0285

Wideband Low Error Vector Magnitude (EVM) Direct Conversion Transmitter

Schematic PCB

MAXREFDES1043: SpO2 monitoring solution based on MAX30102

The MAXREFDES1043 is designed for SpO₂ measurements based on Maxim’s new-generation biosensor—the MAX30102.

Schematic PCB

CN0175

Low-cost, 8-channel, simultaneous sampling data acquisition system with 84 dB SNR and excellent channel-to-channel matching

Schematic PCB

Avalanche Photodiode (APD) Bias Supply and Current Monitoring

This reference design presents a circuit for addressing the power-supply and current-monitoring requirements of APD biasing applications. Based on the MAX15031 DC-DC converter, the application circuit provides a 70V, 4mA, DC-DC power converter with a 2.7V to 11V input supply-voltage range.

Single Cell Li+ Cradle Charger with Linear AC Adapter

The single cell Lithium-ion (Li-ion) battery charger that does not dissipate power (no heat) can also use a low cost linear AC adapter. This application note discusses how to design a simple and low-cost Li-ion charger.

MAXREFDES98#: Non-isolated 5V/2.5A PoE powered equipment power supply

This document details the MAXREFDES98# subsystem reference design, a 36V to 57V input, 5V output, step down, non-isolated power supply capable of 12.5W. Design files and test results are included. Hardware is available for purchase.

CN0159

Universal Serial Bus (USB) Cable Isolator Circuit

Schematic PCB

MAXREFDES1039: 64W and 48W dual output DC-DC Buck converters

The MAX17559 is a dual-output, synchronous step-down controller that drives nMOSFETs. The device uses a constant- frequency, peak-current-mode architecture. The two outputs can be configured as independent voltage rails. Input capacitor size is minimized by running the two outputs 180° out of phase. The IC supports current sensing using either an external current-sense resistor for accuracy or an inductor DCR for improved system efficiency. Current foldback or latch-off limits MOSFET power dissipation under short-circuit conditions. The IC provides independent adjustable soft-starts/stops for each output and can start up monotonically into a pre-biased output. The IC can be configured in either PWM or DCM modes of operation, depending on whether constant-frequency operation or light-load efficiency is desired. The IC operates over the -40°C to +125°C temperature range and is available in a lead(Pb)-free, 7mm x 7mm, 32-pin TQFP, package.

CN0300

12-bit, 4-20mA loop-powered thermocouple measurement system using ARM Cortex-M3

Schematic PCB

CN0321

Fully isolated, single-channel voltage, 4 mA to 20 mA output with HART

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MAXREFDES1194: Five-output, optocoupler-less flyback DC-DC converter using the MAX17690

The MAXREFDES1194 is a no-opto flyback DC-DC power supply that delivers five outputs from a 6V to 60V supply voltage. It is designed for equipment that needs multichannel, isolated power supplies with a wide input voltage range. The MAXREFDES1194 employs the no-opto flyback control technique of the MAX17690. This document explains how the MAX17690 peak current-mode PWM converter can be used to generate five isolated outputs from a 6V to 60V input voltage.

CN0221

USB Thermocouple Temperature Measurement System Using ARM Cortex-M3

Schematic PCB

Power chopper dimming controls boost LED driver efficiency and maintains minimum inrush current

This LED driver reference design drives a 700mA constant current to a single string of LEDs with forward voltages up to 60V. The design allows PWM dimming based on supply chopping. The input power supply is chopped on and off at 300Hz to 1kHz frequency to achieve LED brightness control. The driver uses a fixed-frequency boost converter, controlled by the MAX16834 LED driver. This unique reference design limits the input inrush current to negligible levels without compromising either the input or output filtering. Design schematics and test results are provided.

CN0185

New Analog/Analog Isolator Using Isolated Σ-Δ Modulator, Isolated DC/DC Converter and Active Filter

Schematic PCB

MAXREFDES1153: Multi-cell fuel gauge with battery protection and balancing circuit using MAX17205

The MAXREFDES1153 is a monitoring solution for genuine lithium-ion (Li+) battery packs with 2 to 15 cells connected in series. This reference design provides an accurate state of charge (SOC) in milliamp-hours (mAh) or percentage (%), as well as precision measurements of current, voltage, and temperature for multicell battery packs.

PASADENA (MAXREFDES31#): 3.3V and 5V POE power devices

Pasadena (MAXREFDES31#) is a highly efficient, flyback, 3.3V and 5V Class 4 powered device (PD) with a 40V to 57V auxiliary input. The design features the MAX5969B as the controller. The MAX5974A controls current-mode PWM converters and provides frequency foldback for both the auxiliary input and power-over-Ethernet (PoE) applications. The design is a high-performance, compact, IEEE® 802.3af/at compliant, cost-efficient solution for a PD with power level up to Class 4. The design can also support the auxiliary-input to provide approximately 21W output power.

Schematic PCB

Using MAX15005 for power supply and driving of LED application systems

This reference design is a complete application design for an automotive LED application. It utilizes the MAX15005 current-mode controller to boost a standard lead-acid car battery to 21V for driving a string of automotive LEDs.

Isolated power supplies for telecom applications

Simple easy to use high side current sense amps protects power supplies as a result of irregular supply voltage caused by short-circuit conditions.

IEEE 802.3af compliant single-port, powered device applications

Power-over-Ethernet (PoE) technology enables power-sourcing equipment (PSE, a switch/router or midspan system) to deliver up to 15W of power to IEEE® 802.3af-compliant powered devices like IP phones and wireless LAN access points. This application note describes how to design a single-port PSE system to meet the IEEE 802.3af signature, classification, and power-management requirements. The single-port PSE in this example is designed using the MAX5922A IC.

CN0235

Fully isolated lithium-ion battery monitoring and protection system

Schematic PCB