- Low-Voltage, Step-Down Regulator
THE MAX17083 low-voltage step-down regulator from Maxim Integrated Products features an internal boost switch. Designed for space-constrained applications, the device integrates dual n-channel MOSFET power switches in a 16-mm2 TQFN package.
Supporting a continuous load current up to 5 A, the internal 25-mΩ, low-side power MOSFETs ensure high efficiency while reducing component count. For further space and cost savings, the step-down regulator eliminates the need for external Schottky diodes as well as an external boost diode.
Suitable for low-power compact applications such as ultra-mobile PCs, netbooks, and portable gaming devices, the MAX17803 uses a current-mode, fixed-frequency control scheme to provide an easy-to-implement architecture that does not sacrifice transient response. This architecture also provides peak-current-limit protection and operates in pulse-skipping mode to maintain high efficiency under light-load conditions.
The step-down regulator produces an adjustable 0.75-V to 2.7-V output voltage from the system's 3.3-V or 5-V input supply. The device is fully specified over the -40° to 85°C temperature range.
Prices start at $2.75 (1000-up, FOB USA). An evaluation kit with recommended external components is available to reduce design time.
- Power Resistors
THE CRF1206 and CRM2512-FT power resistors from Bourns provide high power density in a small form factor to satisfy the growing demand for low-power, space-saving devices. Offered in a 1206 case size, the RoHS-compliant CRF1206 is constructed from a stamped metal alloy rated at 1 W and is suited for power supplies and stepper-motor drive applications. Inductance is less than 5 nH, resistances are 0.01 and 0.02 Ω, and TCRs are 100 and 75 ppm/°C, respectively. This resistor is also rated to handle overload conditions equivalent to five times the operating power for up to 5 seconds.
The CRM2512-FT is an SMT power resistor offering a 2-W rating from a 2512 case size. The device meets ITU-T K.20, K.21 and K.45 basic test requirements within rated limits for telecom ports designed for Metallic Ended Line Test (MELT) functionality such as ADSL and VDSL2 hardware or for telecom line test equipment.
As a pricing reference, the CRF1206 power resistor is priced from $0.25 to $0.30 in 10,000 piece quantities and the CRM2512-FT is priced from $0.10 to $0.14 in 8,000 pieces.
- Oscilloscope Probe Positioners
THE N278xA Series oscilloscope probe positioners from Agilent Technologies provide quick and stable probe positioning for making measurements on PC boards and other devices that require hands-free probing. Unlike other probe positioners requiring multiple adjustments to lock the probe holder into position, the N2784A one-arm and N2785A two-arm devices use only a “lift and drop” motion. The weight-stabilization technique used in the probe holder keeps constant pressure at the probing point so the probe tip stays in position even when the target board is bumped.
The N2786A is a low-cost, easy-to-use XY-axis probe holder for general-purpose probing applications. The two-legged positioner is designed to be easy to use; the positioner itself has no controls to position it in place. The N2787A is a 3-D probe positioner with a flexible, articulating arm that can be quickly positioned in a wide variety of configurations and also allows fine adjustments to the probe location to obtain stable contact.
The positioners fit most Agilent passive and active probes, and are also compatible with various probes from other vendors. The Agilent N2784A Series probe positioners are available now, with prices starting at $60.
Santa Clara, CA
- 32-V Monolithic Li-Ion/Polymer Battery Chargers
LINEAR TECHNOLOGY'S LT3650-4.1 and LT3650-4.2 monolithic high-voltage battery chargers for single-cell Li-Ion/Polymer batteries feature a switch-mode architecture that minimizes power dissipation without compromising board space. The battery chargers operate from 4.75 V to 32 V and have a 40-V absolute maximum rating for added system margin.
A user-selectable timer or C/10 termination requires no external microcontroller. Charge current is programmable and dynamically adjustable up to 2 A; the power device is integrated on-chip to save board space. The LT3650-4.1/4.2battery chargers do not require external high-precision resistors to set the float voltage.
Applications include industrial handheld instruments, 12-V to 24-V automotive and heavy equipment, desktop cradle chargers and small notebook or tablet computers. The LT3650-4.1 offers a 4.1-V battery-float voltage that allows high-temperature safety margin, while the LT3650-4.2 features a 4.2-V final-charge voltage for optimized battery run time.
With their current-mode architecture and operation to 1 MHz, the battery chargers enable the use of small inductors and capacitors to minimize noise and filtering needs. Final-float-voltage accuracy is specified at ±0.5%, charge current accuracy is ±5% and C/10 detection accuracy is ±2.5%.
Once charging is terminated, the LT3650-4.1/4.2 chargers automatically enter a low-current standby mode that reduces the input supply current to 85 µA. In shutdown mode, the input bias current is reduced to 15 µA.
The LT3650-4.1 and LT3650-4.2 devices maximize battery life during all non-charging periods, draining less than 1 µA from the battery. For safety and autonomous charge control, the chargers include features such as automatic restart and preconditioning, a thermistor input for temperature-qualified charging, programmable input current limit, bad-battery detection and binary-coded status output pins.
The LT3650-4.1 and LT3650-4.2 are housed in 12-pin 3- × 3-mm DFN packages and are offered in E- and I-grade versions. Both battery chargers operate in temperatures from -40° to 85°C. Pricing starts at $2.80 and $3.22 for the E & I grades, respectively, in 1,000-piece quantities.
- Next-Generation MOSFETs
INFINEON TECHNOLOGIES AG launched its next-generation 600-V CoolMOS C6 Series high-performance MOSFETs. The new C6 technology combines the advantages of modern superjunction or compensation devices, including ultra-low area-specific on-resistance (for example, only 99 mΩ in a TO-220 package), reduced capacitive switching losses, and simplified switching control.
The MOSFETs offer a variety of benefits to power-supply manufacturers including low capacitive losses and very low area specific RDS(on) values, which make the power supplies more efficient, more compact, lighter and cooler. At the same time, the devices improve control of switching behavior and robustness against parasitic inductances and capacitances in the board, which simplifies system layout compared to designs based on the CP series.
In the CoolMOS C6 series the interaction of gate charge, voltage/current slope and internal gate resistance is tuned so that even with very low gate resistances (down to 0 Ω) no excessive voltage or current slopes can appear. Additionally, the C6 devices show high ruggedness against hard commutation of the body diode, which can help to avoid the usage of expensive fast-body-diode components.
The CoolMOS C6 MOSFETs come in values ranging from 70 mΩ to 3.3 Ω. Samples of the IPA60R190C6 providing 600 V with an RDS(on) of 190 mΩ in a TO-220 Fullpack are available. Volume production is scheduled to begin in August 2009.
Pricing for a single unit of the IPA60R190C6 (600-V CoolMOS C6, RDS(on) of 190 mΩ, TO-220 Fullpack) is $0.88 in 10,000-piece quantities, while the IPD60R950C6 (600-V CoolMOS C6, RDS(on) of 950 mΩ, DPAK) is available for $0.30 per piece for the same volume.
- Gear-Tooth Sensor
COMPRISING AN optimized Hall IC/magnet configuration housed in a single over-molded module, the ATS667LSG true-zero-speed gear-tooth sensor from Allegro MicroSystems offers a user-friendly digital gear-tooth sensing solution for a variety of applications. The small package can be easily assembled and used in conjunction with gears of various shapes and sizes.
The ATS667LSG incorporates a dual-element Hall IC that switches in response to differential magnetic signals created by a ferrous target. The IC's compensating circuit eliminates the detrimental effects of magnet and system offsets.
Digital processing of the analog signal provides zero-speed performance independent of air gap and also dynamic adaptation of device performance to the typical operating conditions found in automotive applications (reduced vibration sensitivity). High-resolution peak-detecting DACs and a bounded tracking algorithm are used to set the adaptive switching thresholds of the device.
Adaptive hysteresis in the thresholds reduces the negative effects of any anomalies in the magnetic signal associated with the targets used in many automotive applications. The advanced signal processing suits transmission applications, providing vibration immunity and a large operating air gap capability.
The ATS667LSG gear-tooth sensor is offered in the “SG” magnetically integrated package, a single-step over-molded package comprising a samarium cobalt magnet and a Hall-Effect IC. The PB-free package feaures 100% matte-tin lead-frame plating. Pricing is $2.89 in 1,000 pieces and lead time to market is 14 to 16 weeks.