Datasheet LT3487 (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | Boost and Inverting Switching Regulator for CCD Bias |
| Seiten / Seite | 16 / 1 — FEATURES. DESCRIPTIO. Generates 15V at 45mA, –8V at 90mA from a. Li-Ion … |
| Dateiformat / Größe | PDF / 296 Kb |
| Dokumentensprache | Englisch |
FEATURES. DESCRIPTIO. Generates 15V at 45mA, –8V at 90mA from a. Li-Ion Cell. Output Disconnect
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LT3487 Boost and Inverting Switching Regulator for CCD Bias
U FEATURES DESCRIPTIO
■
Generates 15V at 45mA, –8V at 90mA from a
The LT®3487 dual channel switching regulator generates
Li-Ion Cell
positive and negative outputs for biasing CCD imagers. ■
Output Disconnect
The device delivers up to –8V at 90mA and 15V at 45mA ■
Sequencing: Positive Output Reaches Regulation
from a lithium-ion cell, providing bias for many popular
Before Negative Channel Begins Switching
CCD imagers. The boost regulator incorporates output ■
Internal Schottky Diodes
disconnect technology to eliminate the DC current path ■
2MHz Constant Switching Frequency
from VIN to the output load that is present in standard ■
Requires Only One Resistor per Channel to Set
boost confi gurations. The 2MHz switching frequency
Output Voltages
allows CCD solutions using tiny, low profi le capacitors ■ VIN Range: 2.3V to 16V and inductors and generates low noise outputs that are ■ Output Voltage Up to 28V easy to fi lter. Schottky diodes are internal and the output ■ Short-Circuit Robust voltages are set with one resistor per channel, reducing ■ Capacitor Programmable Soft-Start the external component count. ■ Separate VBAT Pin Allows Separate Sources for Intelligent soft-start allows sequential soft-start of the two Power and Control Circuitry channels with a single capacitor. The soft-start is sequenced ■ Available in 10-Lead (3mm × 3mm) DFN Package
U
such that the output ramp of the negative channel begins
APPLICATIO S
after the ramp of the positive channel. Internal sequencing circuitry also disables the negative channel until the positive ■ CCD Bias channel has reached 87% of its fi nal value, ensuring that ■ TFT LCD Bias the sum of the two outputs is always positive. ■ OLED Bias The LT3487 is available in a 10-pin 3mm × 3mm DFN ■ ±Rail Generation for Op Amps package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
U TYPICAL APPLICATIO Conversion Effi ciency
15µH 10µH 80 POS CHANNEL AT CAP 75 2.2µF SWN VBAT SWP VIN 70 3V TO 12V VIN CAP POS CHANNEL 1µF 65 AT V 549k 100nF POS LT3487 DN FBP 60 NEG CHANNEL 47pF 4.7µF 55 15µH EFFICIENCY (%) 50 VNEG FBN –8V 324k VPOS 45 90mA RUN/SS RUN/SS VPOS 15V VIN = 3.6V 45mA GND 40 22µF 100nF 0 20 40 60 80 100 LOAD CURRENT (mA) 3487 TA01a 3487 TA01b 3487f 1
U FEATURES DESCRIPTIO
■
Generates 15V at 45mA, –8V at 90mA from a
The LT®3487 dual channel switching regulator generates
Li-Ion Cell
positive and negative outputs for biasing CCD imagers. ■
Output Disconnect
The device delivers up to –8V at 90mA and 15V at 45mA ■
Sequencing: Positive Output Reaches Regulation
from a lithium-ion cell, providing bias for many popular
Before Negative Channel Begins Switching
CCD imagers. The boost regulator incorporates output ■
Internal Schottky Diodes
disconnect technology to eliminate the DC current path ■
2MHz Constant Switching Frequency
from VIN to the output load that is present in standard ■
Requires Only One Resistor per Channel to Set
boost confi gurations. The 2MHz switching frequency
Output Voltages
allows CCD solutions using tiny, low profi le capacitors ■ VIN Range: 2.3V to 16V and inductors and generates low noise outputs that are ■ Output Voltage Up to 28V easy to fi lter. Schottky diodes are internal and the output ■ Short-Circuit Robust voltages are set with one resistor per channel, reducing ■ Capacitor Programmable Soft-Start the external component count. ■ Separate VBAT Pin Allows Separate Sources for Intelligent soft-start allows sequential soft-start of the two Power and Control Circuitry channels with a single capacitor. The soft-start is sequenced ■ Available in 10-Lead (3mm × 3mm) DFN Package
U
such that the output ramp of the negative channel begins
APPLICATIO S
after the ramp of the positive channel. Internal sequencing circuitry also disables the negative channel until the positive ■ CCD Bias channel has reached 87% of its fi nal value, ensuring that ■ TFT LCD Bias the sum of the two outputs is always positive. ■ OLED Bias The LT3487 is available in a 10-pin 3mm × 3mm DFN ■ ±Rail Generation for Op Amps package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
U TYPICAL APPLICATIO Conversion Effi ciency
15µH 10µH 80 POS CHANNEL AT CAP 75 2.2µF SWN VBAT SWP VIN 70 3V TO 12V VIN CAP POS CHANNEL 1µF 65 AT V 549k 100nF POS LT3487 DN FBP 60 NEG CHANNEL 47pF 4.7µF 55 15µH EFFICIENCY (%) 50 VNEG FBN –8V 324k VPOS 45 90mA RUN/SS RUN/SS VPOS 15V VIN = 3.6V 45mA GND 40 22µF 100nF 0 20 40 60 80 100 LOAD CURRENT (mA) 3487 TA01a 3487 TA01b 3487f 1