REG103-5 Linear Regulator

General Description

The REG103 is a family of low-noise, low-dropout, linear regulators with low ground pin current. Its new DMOS topology provides significant improvement over previous designs, including low dropout voltage (only 115mV typ at full load), and better transient performance. In addition, no output capacitor is required for stability, unlike conventional low dropout regulators that are difficult to compensate and require expensive low ESR capacitors greater than 1µF.

Typical ground pin current is only 1mA (at IOUT = 500mA) and drops to 0.5µA in not enabled mode. Unlike regulators with PNP pass devices, quiescent current remains relatively constant over load variations and under dropout conditions.

The REG103 has very low output noise (typically 33µVrms for VOUT = 3.3V with CNR = 0.01µF), making it ideal for use in portable communications equipment. On-chip trimming results in high output voltage accuracy. Accuracy is maintained over temperature, line, and load variations. Key parameters are tested over the specified temperature range (–40°C to +85°C).

The SO-8 version of the REG103 has an ERROR\ pin that provides a power good flag, indicating the regulator is in regulation. The REG103 is well protected—internal circuitry provides a current limit that protects the load from damage. Thermal protection circuitry keeps the chip from being damaged by excessive temperature. In addition to the SO-8 package, the REG103 is also available in the DDPAK and the SOT223-5.

Features

• NEW DMOS TOPOLOGY:
  • Ultra Low Dropout Voltage:
    • 115mV Typ at 500mA and 3.3V Output
  • Output Capacitor NOT Required for Stability
• FAST TRANSIENT RESPONSE
• VERY LOW NOISE: 33 µVrms
• HIGH ACCURACY: ±2% max
• HIGH EFFICIENCY:
  • IGND = 1mA at IOUT = 500mA
  • Not Enabled: IGND = 0.5 µA
• 2.5V, 2.7V, 3.0V, 3.3V, 5.0V, AND ADJUSTABLE OUTPUT VERSIONS
• FOLDBACK CURRENT LIMIT
• THERMAL PROTECTION
• OUTPUT VOLTAGE ERROR INDICATOR(1)
• SMALL SURFACE-MOUNT PACKAGES:
  SOT223-5, DDPAK-5, SO-8
• APPLICATIONS
• PORTABLE COMMUNICATION DEVICES
• BATTERY-POWERED EQUIPMENT
• PERSONAL DIGITAL ASSISTANTS
• MODEMS
• BAR-CODE SCANNERS
• BACKUP POWER SUPPLIES

Parametrics