Power

Application Notes

Ping-Pong Configuration Increases the Number of Monitored Power-Supply Inputs

AN-0997: Ping-Pong Configuration Guide for ADM1062 to ADM1069 Devices

The ADM1062 to ADM1069 Super Sequencers^® offer a single-chip solution for supply monitoring and sequencing in multiple-supply systems. The ADM1062 to ADM1067 can monitor up to ten input rails (VH, VP1 to VP4, and VX1 to VX5)., while the ADM1068 and ADM1069 can monitor up to eight input rails (VH, VP1 to VP3, and VX1 to VX4). Two programmable comparators enable both undervoltage and overvoltage sensing with ±1% accuracy. For some applications, the number of the input rails exceeds the number of input pins on a single device. In these cases, multiple devices can be linked together to form a more powerful sequencer. A simple configuration allows devices to be able to hand off control of the sequencing process on request, minimizing the number of physical links needed for communicating between devices and maintaining fast system fault response. The ping-pong configuration lets devices exchange control of the sequencing process by transmitting pulse signals forward and backwards like a ping-pong ball. This 12-page Application Note explains the concept and implementation of the ping-pong configuration.

New Product Briefs

March 2010

Isolated Half-Bridge Driver provides 4-A peak output currents

The ADuM7234 isolated half-bridge gate driver uses iCoupler^® technology to provide independent, isolated outputs for driving the gates of the high-side and low-side IGBT and MOSFET devices used in plasma displays, switching power supplies, and industrial inverters. Combining high-speed CMOS with monolithic micro-transformers, iCoupler technology provides precise timing, high reliability, and better overall performance than optocoupler-based systems. Each output can be driven up to ±350 V_PEAK with respect to the input and with a differential of up to 350 V_PEAK working voltage between the high side and the low side. Switching at up to 1 MHz, the outputs can provide 4-A peak currents. The CMOS-compatible inputs provide 25-kV/μs common-mode transient immunity. Operating on a 4.5-V to 5.5-V input supply, the ADuM7234 consumes 1 mA. Available in a 16-lead SOIC package, it is specified from –40°C to +105°C and priced at $1.82 in 1000s.

Five-channel Digital Isolator provides 1-kV rms isolation

The ADuM7510 five-channel digital isolator provides superior performance to and lower cost than optocouplers. Using patented iCoupler^® technology, it combines high-speed CMOS with integrated micro-transformers, eliminating the uncertain current-transfer ratios, nonlinear transfer functions, and drift (with time and temperature) associated with optocouplers. Power consumption is as much as 90% less, and no external drivers or discrete devices are required. Providing 1-kV isolation and 25 kV/μs common-mode transient immunity, it meets UL safety- and regulatory requirements; CSA approval is pending. The device features 5-ns pulse-width distortion, 5-ns channel-to-channel mismatch, and 10-Mbps max data rates. The power supplies on each side can range from 4.5 V to 5.5 V, allowing level-translation across the isolation barrier. Refresh circuitry ensures correct output data levels in the absence of input transitions—and during power-up and power-down conditions. Available in a 16-lead QSOP package, the ADuM7150 is specified from –40°C to +105°C and priced at $2.70 in 1000s.

Very-Low-Dropout Regulators drive loads of up to 500 mA

The ADP124 and ADP125 low-dropout regulators are available in 31 fixed-output options from 1.75 V to 3.3 V (ADP124) and a 0.8-V to 5-V adjustable output (ADP125). With ±1% initial accuracy and –2/+1.5% accuracy over line, load, and temperature, they feature 130-mV dropout voltage with a 500-mA load. Stable with tiny ceramic input and output capacitors, their robust design features a fixed 350-µs soft-start time, short-circuit protection, and thermal-overload protection. Operating on a single 2.3-V to 5.5-V supply, the ADP124/25 draw 210 μA at full load, 45 μA with no load, and 100 nA in shutdown mode. Available in 8-lead exposed-paddle mini-SOIC packages, which improve junction-to-board thermal resistance to 32°C/W vs. standard MSOP package, they are specified from –40°C to +125°C and priced at $0.42 in 1000s.

February 2010

Mobile I/O Expander and QUERTY Keypad Controller

The ADP5587 port expander and keypad controller features keypad scanning, debouncing, and I/O generation, resulting in simplified routing, reduced processor involvement, and lower power consumption. Offloading key-scan and GPIO functions from the CPU, it enables the processor to control up to 18 data lines—configured as an 8 x 10 keypad matrix or as general-purpose I/Os—via an I²C-compatible bus. Storing key presses and releases, and flagging them to the processor, the controller manages all mobile key scanning and decoding functions. This enables portable devices with QWERTY keypads to use three control lines instead of 18, reducing cost and improving reliability. A key-event counter allows the device to manage up to ten unprocessed key events, while the key-lock capability can trigger an interrupt when the lock sequence is activated. Operating on a 1.7-V to 3.6-V power supply, the ADP5587 draws 55 μA at 1.8 V. Specified from –40°C to +85°C, it is available in a 24-lead LFCSP package and priced at $1.15 in 1000s.

January 2010

Step-down DC-to-DC Converter provides two 3-A outputs or single 6-A output

The ADP2116 high-efficiency step-down dc-to-dc converter is available in six fixed-output options, from 0.8 V to 3.3 V, plus an adjustable-output option that can be set as low as 0.6 V. Featuring output accuracy to within 1.5% and 95% efficiency, it can be configured to deliver: a pair of independent 3-A outputs, 3-A and 2-A outputs, or a single, interleaved 6-A output with reduced output ripple. The switching frequency can be set to 300 kHz, 600 kHz, or 1.2 MHz—or it can be synchronized to an external clock in the 200-kHz to 2-MHz range. Optimized gate slew-rate reduces EMI emissions. The robust design features programmable soft-start time, short-circuit- and thermal-overload protection, and under-voltage lockout. Operating on a single 2.7-V to 5.5-V supply, the ADP2116 consumes 3.4 mA with dual independent outputs, 3 mA with a single output, and 1 µA in shutdown mode. Available in a 32‑lead LFCSP package, it is specified from –40°C to +125°C and priced at $3.17 in 1000s.

Dual 3-MHz, 600-mA Buck Regulator with 150-mA LDO

The ADP5022 micropower management unit (micro PMU) combines two high-performance buck (step-down) regulators and a low-dropout (LDO) linear regulator in a single small package. Further minimizing PC-board space requirements, the buck regulators’ high switching frequency allows the use of tiny external components; and the two bucks operate out of phase to use smaller input capacitors while reducing noise. Normally operating in PWM mode, they draw 24 µA per channel, automatically switching to power-saving mode to improve light-load efficiency. Drawing 11 µA, the LDO has a dropout voltage of 7 mV with a 10-mA load and 110 mV with a 150-mA load. The ADP5022 is available in three factory configured options: the -1 has 3.3-V and 1.5-V buck outputs, 1.8-V LDO output, and 2.4-V undervoltage lockout; the -2 has 1.2-V and 1.8-V buck outputs, 2.8-V LDO output, and 2.4-V undervoltage lockout; and the -3 has 3.3-V and 1.8-V buck outputs, 3.3-V LDO output, and 4.5-V undervoltage lockout. Available in a 16-ball WLFCSP package, the ADP5022 is specified from –40°C to +125°C and priced at $1.80 in 1000s.

Pre-Release Products

December 2009

The AD7280 Lithium-Ion Battery-Monitoring System contains all of the functions required for monitoring battery stacks in hybrid-electric vehicles. Multiplexing six voltage inputs and six temperature inputs into a 12-bit, 1-Msps ADC, it monitors up to six cells. Functionally complete, it includes a voltage reference, channel sequencer, alert function, cell-balancing interface, self-test feature, and daisy-chain interface.

Technical Articles

Steven Boyle, Lithium Ion Battery Monitoring – Redundancy Required?, ECN, 1/28/2010

Matt Kessler, ADIsimPower Provides Robust, Customizable DC-to-DC Converter Designs, Analog Dialogue, 1/6/2010

Ken Marasco, Running Low and Long, Appliance Magazine, 12/2/2009

Webinars and Tutorials

Powering FPGAs - Learn the Basics -- This webinar describes the special power requirements for FPGAs and the appropriate power products used to ensure trouble free operation. A versatile dc-to-dc regulator that is optimized for powering high-performance FPGAs is featured.

Designing with Switching Regulators in High-Speed A/D Converter Applications -- Improve system efficiency with no performance degradation using switching power supplies in high-speed A/D converter applications.

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