Linear's New DC/DC Converter and ADC

Date
01/13/2011

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60V Synchronous Step-Down DC/DC Controller Specified up to 150°C

60V Synchronous Step-Down Controller Operates up to 150°C

Linear Technology Corporation introduces the LTC3810H-5, a high input voltage synchronous step-down DC/DC controller with guaranteed specifications for junction temperatures as high as 150°C. This device employs a constant on-time valley current-mode control architecture, delivering very low duty cycles and extremely fast transient response with accurate cycle-by-cycle current limit without requiring a sense resistor. This rugged controller can directly step down voltages from 60V to an output voltage ranging from 0.8V to 93% of VIN. The powerful 1 Ohm onboard gate drivers minimize switching losses associated with driving N-channel MOSFETs at high frequency and high voltage for output currents up to 25A. Applications include 48V power conversion in telecom and datacom, as well as automotive and industrial systems susceptible to high surge voltages. The LTC3810-5 features an adjustable minimum on-time that can be set as low as 100ns, enabling a high step-down ratio at high frequency. The operating frequency is selectable from 100kHz to 1MHz or can be synchronized to an external clock over the same range. Pulse skipping operation can be configured to maintain high efficiency at light loads. Additional features include programmable soft start or tracking, adjustable cycle-by-cycle current limit, output overvoltage protection, power good output signal and programmable undervoltage lockout. Summary of Features: LTC3810H-5

  • -40°C to 150°C Guaranteed Junction Temperature Operation
  • Up to 60V Input Voltage Operation
  • Wide Output Voltage Range from 0.8V to 0.93VIN
  • Synchronous Rectification
  • Adjustable Low Constant On-Time Down to 100ns
  • Valley Current-Mode Control
  • Large 1 Ohm Gate Drivers
  • No Current Sense Resistor Required
  • Power Good Output Signal
  • Adjustable Cycle-by-Cycle Current Limit
  • 100kHz to 1Mhz Selectable Frequency or Synchronizable to an External Clock
  • Selectable Pulse Skipping or Continuous Operation
The LTC3810H-5 is offered in a 5mm x 5mm QFN-32 package. For more information, visit www.linear.com/3810

Linear Technology Corporation introduces the LTC2379-18, a serial 18-bit, 1.6Msps SAR analog to digital converter (ADC) that achieves an unrivaled 101dB SNR and -118dB THD while supporting a fully differential ±5V input range. This breakthrough performance establishes Linear's position as a leader in high performance ADCs. The LTC2379-18 features a maximum INL of ±2LSB with no missing codes and guaranteed specifications over the -40°C to 125°C temperature range. Operating from a 2.5V supply, the LTC2379-18 consumes only 18mW and is available in small 3mm x 4mm DFN and MSOP-16 packages. The LTC2379-18's high SNR, fast throughput and low power dissipation make it ideal for high performance medical, industrial and automotive applications. Complementing the LTC2379-18 is the pin- and software-compatible 16-bit, 2Msps LTC2380-16. The LTC2380-16 achieves an impressive 96dB SNR and ±0.5LSB maximum INL. The LTC2379-18 and LTC2380-16 are the first in a family of 18-/16-bit high performance SAR ADCs with speeds ranging from 250ksps up to 2Msps. These devices offer a revolutionary new digital gain compression feature that eliminates the need for a negative supply on the ADC driver, dramatically lowering the total power consumption of the signal chain. The devices' shutdown mode further reduces power dissipation to 1.25μW when idle. The true no-latency operation enables accurate one-shot measurements even after lengthy idle periods with no minimum sample rate required. The explicit Busy and Chain pins, along with a user-friendly SPI interface, support I/O voltages from 1.8V to 5V, simplify digital timing and minimize external component count. Summary of Features: LTC2379-18

  • 1.6Msps Throughput Rate
  • ±2LSB INL (Max)
  • Guaranteed 18-Bit No Missing Codes
  • Low Power: 18mW at 1.6Msps, 18?W at 1.6ksps
  • 101dB SNR (typ) at fIN = 2kHz
  • Guaranteed Operation to 125°C
  • 2.5V Supply
  • Fully Differential Input Range ±VREF
  • VREF Input Range from 2.5V to 5.1V
  • No Pipeline Delay, No Cycle Latency
  • 1.8V to 5V I/O Voltages
  • SPI-Compatible Serial I/O with Daisy-Chain Mode
  • Internal Conversion Clock
  • 16-pin MSOP and 4mm x 3mm DFN Packages
The LTC2379-18 and LTC2380-16 are now available, priced at $29.95 each for the LTC2379-18 and $24.50 each for the LTC2380-16 in 1,000 piece quantities. To achieve uncompromised AC performance, we recommend the fast settling LT6350 ADC driver for single-ended to differential conversion of input signals. We also recommend the LTC6655, a precision external reference with high accuracy, low noise and low power. The DC1783A, an integrated demo board featuring the LT6350 ADC driver and LTC6655 reference, is available at www.linear.com or via a local Linear Technology sales office. For more information, visit www.linear.com/2379

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