LTC7802EUFDM datasheet(8/34 Pages) AD

8 / 34 page

LTC7802

Rev. 0

For more information www.analog.com

PIN FUNCTIONS

SENSE1+, SENSE2+ (Pins 1,8): The Positive (+) Input

to the Differential Current Comparators. The ITH pin

voltage and controlled offsets between the SENSE– and

SENSE+ pins in conjunction with RSENSE set the current

trip threshold.

SENSE1–, SENSE2– (Pins 2,7): The Negative (–) Input to

the Differential Current Comparators. The SENSE– pins

supply current to the current comparators when they are

greater than INTVCC. When SENSE1– is 3.2V or greater,

it also supplies the majority of the sleep mode quiescent

current instead of VIN, further reducing the input-referred

quiescent current.

TYPICAL PERFORMANCE CHARACTERISTICS

FREQ (Pin 3): Frequency Control Pin for the Internal

Oscillator. Connect to ground to set the switching fre-

quency to 350kHz. Connect to INTVCC to set the switching

frequency to 2.25MHz. Frequencies between 100kHz and

3MHz can be programmed using a resistor between the

FREQ pin and ground. Minimize the capacitance on this pin.

MODE (Pin 4): Mode Select Input. This input, which acts

on both channels, determines how the LTC7802 operates

at light loads. Pulling this pin to ground selects Burst

Mode operation. An internal 100k resistor to ground also

invokes Burst Mode operation when the pin is floating.

INTVCC Load Regulation

EXTVCC Switchover and INTVCC

Voltage vs Temperature

INTVCC Undervoltage Lockout

Thresholds vs Temperature

Quiescent Current

vs Temperature

Shutdown Current vs VIN Voltage

TRACK/SS Pull-Up Current

vs Temperature

VIN = 12V

EXTVCC = 0V

EXTVCC = 5V

EXTVCC = 6V

INTVCC LOAD CURRENT (mA)

100

150

200

250

300

4.0

4.2

4.4

4.6

4.8

5.0

5.2

5.4

7802 G19

INTVCC VOLTAGE

EXTVCC RISING

EXTVCC FALLING

VIN = 12V

TEMPERATURE (°C)

–55 –25

125 155

4.2

4.4

4.6

4.8

5.0

5.2

5.4

7802 G20

RISING

FALLING

TEMPERATURE (°C)

–55 –25

125 155

3.7

3.8

3.9

4.0

4.1

4.2

4.3

4.4

Thresholds vs Temperature

7802 G21

ONLY CHANNEL 1 ON

SLEEP MODE

VIN = 12V

EXTVCC = 5V

SENSE1– = 3.3V

EXTVCC = 0V

SENSE1– = 3.3V

EXTVCC = 0V

SENSE1– = 0V

TEMPERATURE (°C)

–55 –25

125 155

7802 G22

155°C

25°C

–55°C

125°C

VIN VOLTAGE (V)

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

7802 G23

TEMPERATURE (°C)

–55 –25

125 155

7802 G24

LTC7802EUFDM Datasheet(PDF) 8 Page - Analog Devices

LTC7802EUFDM Datasheet(HTML) 8 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

Datasheet Download

Link URL