Regulated 2.5V and 3.3V 150mA Buck-Boost Charge Pumps in 2 × 2 DFN Package

Apr 24 2006 -MILPITAS, CA
  • Linear Technology Corporation announces the LTC3240-2.5/3.3, versatile regulated buck-boost charge pumps in a 2mm × 2mm DFN package. The LTC3240-2.5/3.3 are capable of output currents as high as 150mA from a wide ranging input of 1.8V to 5.5V. When the input voltage exceeds the output voltage, the device operates in low-dropout regulator (LDO) mode. If the input voltage drops to within 100mV of the output voltage, the device automatically switches into a step-up (boost) mode. For light loads it operates in a high-efficiency, low power Burst Mode® to extend battery life.

    When boosting higher loads the LTC3240 automatically switches into low noise constant frequency operation. Its patented constant-frequency architecture offers both low input and low output ripple and its high 1.2MHz switching frequency enables the use of tiny external ceramic capacitors, saving size and cost. Low external parts count of one flying capacitor and two bypass capacitors, in addition to the low profile (0.75mm) 2mm × 2mm DFN package make the LTC3240 an extremely compact solution for space-constrained applications. Other features include soft start to prevent excessive inrush current during startup, output disconnect during shutdown, plus current limit and thermal shutdown circuitry.

    Featuring a regulated output, the tiny LTC3240 is well suited for a variety of applications such as 2-3 AA cell alkaline/NiMH or 1-cell Li-Ion battery to 2.5V/3.3V step-up/step-down conversion in portable products. These include digital cameras, PDAs, media players, measurement instruments and cellular phones. The device's low ripple performance makes it ideal for applications sensitive to variable-frequency operation such as audio and RF supplies as well as thin PC and I/O cards.

    The LTC3240EDC-2.5 and LTC3240EDC-3.3 are available from stock in a 6-lead DFN (2mm × 2mm × 0.75mm) package. 1,000-piece pricing starts at $1.60 each.

    Summary of Features: LTC3240

    • Step-Up/Step Down Charge Pump Topology
    • Fixed Outputs:
      • 2.5V for LTC3240-2.5
      • 3.3V for LTC3240-3.3
    • Wide VIN Range: 1.8V to 5.5V
    • Output Current: up to 150mA
    • Constant Frequency (1.2MHz) Charge Pump Doubler Operation in Step-Up Mode
    • Automatic Burst Mode Operation at Light Load Increases Efficiency
    • Low Dropout Regulator Operation in Step-Down Mode
    • Low No-Load Quiescent Current: IQ = 65uA
    • Low Shutdown Current
    • Low Input and Output Ripple
    • Shutdown Disconnects Load from Input
    • Low Profile 6-Pin DFN (2mm × 2mm × 0.75mm) Package
    LTC3240 PR Image

    Download PDF version

  • Editor's Contact Information
Stay Informed