1 Features
1• 1% Voltage Accuracy at Room Temperature
• Stable with Ceramic Capacitor
• Logic Controlled Enable
• No Noise Bypass Capacitor Required
• Thermal-Overload and Short-Circuit Protection
• Input Voltage Range, 2 V to 6 V
• Output Voltage Range, 0.8 V to 3.3 V
• Output Current, 150 mA
• Output Stable - Capacitors, 1 μF
• Virtually Zero IQ (Disabled), < 10 nA
• Very Low IQ (Enabled), 43 μA
• Low Output Noise, 150 μVRMS
• PSRR, 55 dB at 1 kHz
• Fast Start-Up, 105 μs

2 Applications
• Cellular Handsets
• Hand-Held Information Appliances

3 Description
The LP3990 regulator is designed to meet the
requirements of portable, battery-powered systems providing an accurate output voltage, low-noise, and
low-quiescent current. The LP3990 will provide a 0.8-
V output from the low input voltage of 2 V at up to a
150-mA load current. When switched into shutdown mode via a logic signal at the enable pin (EN), the
power consumption is reduced to virtually zero.
The LP3990 is designed to be stable with space-
saving ceramic capacitors with values as low as 1 μF.
Performance is specified for a –40°C to 125°C
junction temperature range.
For output voltages other than 0.8 V, 1.2 V, 1.35 V,
1.5 V, 1.8 V, 2.5 V, 2.8 V, or 3.3 V, please contact
the Texas Instruments sales office.