–20V, 200mA Negative Linear Regulator with Ultralow Noise and Ultrahigh PSRR

The LT®3093 from Analog Devices is a high-performance low dropout negative linear regulator. It features ADI's ultralow noise and ultrahigh PSRR architecture for powering noise-sensitive applications. The device can be easily paralleled, reducing noise, increasing output current, and spreading heat on a PCB.

Typical applications for the negative linear regulator include RF and precision power supplies, very low noise instrumentation, high speed/high precision data converters, post-regulators for switching supplies, and medical applications such as diagnostics and imaging.

The LT3093 supplies 200mA at a typical 190mV dropout voltage. Operating quiescent current is nominally 2.35mA and drops to 3µA in shutdown. The device's wide output voltage range (0V to -19.5V) error amplifier operates in unity-gain and provides virtually constant output noise, PSRR, bandwidth, and load regulation independent of the programmed output voltage.

The ultralow RMS noise is 0.8µVRMS (10Hz to 100kHz), and the ultralow spot noise is 2.2nV/√Hz at 10kHz. With an ultrahigh PSRR of 73dB at 1MHz it has an output current of 200mA and features a wide input voltage range of -1.8V to -20V. A single capacitor improves both noise and PSRR

Additional features include fast startup capability, a bipolar enable pin, programmable current limit, and programmable power good to indicate

output voltage regulation. An incorporated tracking function can control an upstream supply for maintaining a constant voltage across the LT3093, to help minimize power dissipation and optimize PSRR.

With a minimum 4.7µF ceramic output capacitor, the LT3093 is stable.

Built-in protection includes an internal current limit with foldback and thermal limit with hysteresis. The negative LDO can operate between -40°C to 125°C or -40°C to 150°C depending on the variant.

The LT3093 comes in thermally-enhanced 12-Lead MSOP and 3mm × 3mm DFN Packages.

Features

• Ultralow RMS Noise: 0.8µVRMS (10Hz to 100kHz)
• Ultralow Spot Noise: 2.2nV/√Hz at 10kHz
• Ultrahigh PSRR: 73dB at 1MHz
• Output Current: 200mA
• Wide Input Voltage Range: -1.8V to -20V
• Single Capacitor Improves Noise and PSRR
• 100µA SET Pin Current: ±1% Initial Accuracy
• Single Resistor Programs Output Voltage
• Programmable Current Limit
• Low Dropout Voltage: 190mV
• Output Voltage Range: 0V to -19.5V
• Programmable Power Good and Fast Start-Up
• Bipolar Precision Enable/UVLO Pin
• VIOC Pin Controls Upstream Regulator to Minimize Power Dissipation and Optimize PSRR
• Minimum Output Capacitor: 4.7µF Ceramic
• 2-Lead MSOP and 3mm × 3mm DFN Packages