LT3487 - Boost and Inverting Switching Regulator for CCD Bias

Features

  • Generates 15V at 45mA, –8V at 90mA from a Li-Ion Cell
  • Output Disconnect
  • Sequencing: Positive Output Reaches Regulation Before Negative Channel Begins Switching
  • Internal Schottky Diodes
  • 2MHz Constant Switching Frequency
  • Requires Only One Resistor per Channel to Set Output Voltages
  • VIN Range: 2.3V to 16V
  • Output Voltage Up to 28V
  • Short-Circuit Robust
  • Capacitor Programmable Soft-Start
  • Separate VBAT Pin Allows Separate Sources for Power and Control Circuitry
  • Available in 10-Lead (3mm × 3mm) DFN Package

Typical Application

LT3487 Typical Application
LT3487 Typical Application

Description

The LT3487 dual channel switching regulator generates positive and negative outputs for biasing CCD imagers. The device delivers up to –8V at 90mA and 15V at 45mA from a lithium-ion cell, providing bias for many popular CCD imagers. The boost regulator incorporates output disconnect technology to eliminate the DC current path from VIN to the output load that is present in standard boost configurations. The 2MHz switching frequency allows CCD solutions using tiny, low profile capacitors and inductors and generates low noise outputs that are easy to filter. Schottky diodes are internal and the output voltages are set with one resistor per channel, reducing the external component count.

Intelligent soft-start allows sequential soft-start of the two channels with a single capacitor. The soft-start is sequenced such that the output ramp of the negative channel begins after the ramp of the positive channel. Internal sequencing circuitry also disables the negative channel until the positive channel has reached 87% of its final value, ensuring that the sum of the two outputs is always positive.

The LT3487 is available in a 10-pin 3mm × 3mm DFN package.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LT3487EDD#PBF 3x3 DFN-10 DD E 05-08-1699 Yes
LT3487EDD#TRPBF 3x3 DFN-10 DD E 05-08-1699 Yes


LT3487 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT3487EDD#PBF 3x3 DFN-10 E $3.29 $2.30 Yes
LT3487EDD#TRPBF 3x3 DFN-10 E $2.36 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC912A LT3487EDD Demo Board $100.00
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Click here to view our complete list of demo boards

Applications

  • CCD Bias
  • TFT LCD Bias
  • OLED Bias
  • ±Rail Generation for Op Amps

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LT3487

Technical Support