特徴

  • Ultralow RMS Noise: 0.8µVRMS (10Hz to 100kHz)
  • 超低スポットノイズ：10kHzで2nV/√Hz
  • Ultrahigh PSRR: 76dB at 1MHz
  • Output Current: 500mA
  • 広い入力電圧範囲：1.8V〜20V
  • シングル・コンデンサーでノイズとPSRRを改善
  • 100µA SET Pin Current: ±1% Initial Accuracy
  • 単一抵抗プログラム出力電圧
  • 高帯域幅：1MHz
  • プログラマブル電流制限
  • Low Dropout Voltage: 260mV
  • 出力電圧範囲0V〜15V
  • プログラマブル・パワー・グッド
  • 迅速な立ち上げ能力
  • 精密イネーブル/UVLO
  • 低ノイズと大電流を実現するパラレル方式
  • フォールドバック付き内部電流制限
  • Minimum Output Capacitor: 10µF Ceramic
  • Reverse-Battery and Reverse-Current Protection
  • 12-Lead MSOP and 10-Lead 3mm × 3mm DFN Packages
  • 自動車用AEC-Q100認定

 

アプリケーション

  • RF Power Supplies: PLLs, VCOs, Mixers, LNAs, PAs
  • 超低ノイズ計測器
  • 高速/高精度データ・コンバータ
  • 医療用途イメージング、診断
  • 精密電源
  • スイッチング電源用ポストレギュレータ

 

説明

The LT3045 is a high performance low dropout linear regulator featuring LTC’s ultralow noise and ultrahigh PSRR architecture for powering noise sensitive applications. Designed as a precision current reference followed by a high performance voltage buffer, the LT3045 can be easily paralleled to further reduce noise, increase output current and spread heat on the PCB.The device supplies 500mA at a typical 260mV dropout voltage. Operating quiescent current is nominally 2.2mA and drops to <<1µA in shutdown. The LT3045’s wide output voltage range (0V to 15V) while maintaining unitygain operation provides virtually constant output noise, PSRR, bandwidth and load regulation, independent of the programmed output voltage. Additionally, the regulator features programmable current limit, fast start-up capability and programmable power good to indicate output voltage regulation.The LT3045 is stable with a minimum 10µF ceramic output capacitor. Built-in protection includes reverse-battery protection, reverse-current protection, internal current limit with foldback and thermal limit with hysteresis. The LT3045 is available in thermally enhanced 12-Lead MSOP and 10-Lead 3mm × 3mm DFN packages.

 

アプリケーション情報

The LT3045 is a high performance low dropout linear regulator featuring LTC’s ultralow noise (2nV/√Hz at 10kHz) and ultrahigh PSRR (76dB at 1MHz) architecture for powering noise sensitive applications. Designed as a precision current source followed by a high performance rail-to-rail voltage buffer, the LT3045 can be easily paralleled to further reduce noise, increase output current and spread heat on the PCB. The device additionally features programmable current limit, fast start-up capability and programmable power good.The LT3045 is easy to use and incorporates all of the protection features expected in high performance regulators. Included are short-circuit protection, safe operating area protection, reverse battery protection, reverse current protection, and thermal shutdown with hysteresis.The benefit of using a current reference compared with a voltage reference as used in conventional regulators is that the regulator always operates in unity gain configuration, independent of the programmed output voltage. This allows the LT3045 to have loop gain, frequency response and bandwidth independent of the output voltage. As a result, noise, PSRR and transient performance do not change with output voltage. Moreover, since none of the error amp gain is needed to amplify the SET pin voltage to a higher output voltage, output load regulation is more tightly specified in the hundreds of microvolts range and not as a fixed percentage of the output voltage.Since the zero TC current source is highly accurate, the SET pin resistor can become the limiting factor in achieving high accuracy. Hence, it should be a precision resistor. Additionally, any leakage paths to or from the SET pin create errors in the output voltage. If necessary, use high quality insulation (e.g., Teflon, Kel-F); moreover, cleaning of all insulating surfaces to remove fluxes and other residues may be required. High humidity environments may require a surface coating at the SET pin to provide a moisture barrier.