Datasheet LT3094 (Analog Devices)

LT3094 –20V, 500mA, Ultralow Noise, Ultrahigh PSRR Negative Linear Regulator
FEATURES DESCRIPTION
n
Ultralow RMS Noise: 0.8µVRMS (10Hz to 100kHz)
The LT®3094 is a high performance low dropout negative n
Ultralow Spot Noise: 2.2nV/√Hz at 10kHz
linear regulator featuring ADI’s ultralow noise and ultrahigh n
Ultrahigh PSRR: 74dB at 1MHz
PSRR architecture for powering noise sensitive applica- n
Output Current: 500mA
tions. The device can be easily paralleled to further reduce n
Wide Input Voltage Range: –1.8V to –20V
noise, increase output current and spread heat on a PCB. n
Single Capacitor Improves Noise and PSRR
The LT3094 supplies 500mA at a typical 235mV dropout n
100µA SET Pin Current: ±1% Initial Accuracy
voltage. Operating quiescent current is nominally 2.35mA n Single Resistor Programs Output Voltage and drops to 3µA in shutdown. The device’s wide output n Programmable Current Limit voltage range (0V to –19.5V) error amplifier operates in n Low Dropout Voltage: 235mV unity-gain and provides virtually constant output noise, n Output Voltage Range: 0V to –19.5V PSRR, bandwidth, and load regulation independent of n Programmable Power Good and Fast Start-Up the programmed output voltage. Additional features are a n Bipolar Precision Enable/UVLO Pin bipolar enable pin, programmable current limit, fast start- n VIOC Pin Controls Upstream Regulator to Minimize up capability and programmable power good to indicate Power Dissipation and Optimize PSRR output voltage regulation. The regulator incorporates a n Minimum Output Capacitor: 10µF Ceramic tracking function to control an upstream supply to maintain n 12-Lead MSOP and 3mm × 3mm DFN Packages a constant voltage across the LT3094 to minimize power dissipation and optimize PSRR.
APPLICATIONS
The LT3094 is stable with a minimum 10µF ceramic out- n put capacitor. Built-in protection includes internal current RF and Precision Power Supplies n limit with foldback and thermal limit with hysteresis. The Very Low Noise Instrumentation n LT3094 is available in thermally enhanced 12-Lead MSOP High Speed/High Precision Data Converters n and 3mm × 3mm DFN Packages. Medical Applications: Diagnostics and Imaging n Post-Regulator for Switching Supplies All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION Power Supply Ripple Rejection
120 4.7µF 33.2k 50k 7.5k 105 3.3V 90 450k LT3094 SET GND ILIM PGFB 75 200k OUTS 10µF V 60 OUT PG + OUT –3.3V PSRR (dB) I 45 OUT(MAX) 500mA VIN = –5V 30 R EN/UV SET = 33.2k – COUT = 10µF 15 CSET = 4.7µF IL = –500mA 10µF 100µA 010 100 1k 10k 100k 1M 10M IN VIN FREQUENCY (Hz) –5V 3094 TA01b 3094 TA01a PIN NOT USED IN THIS CIRCUIT: VIOC Rev. B Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Typical Application Related Parts