4

LT1500/LT1501

ELECTRICAL CHARACTERISTICS

temperature range.

Note 1: Feedback pin or output is held sightly above the regulated value to

Note 2: See Typical Performance Characteristics for graph of Guaranteed

Switch Voltage vs Saturation Voltage.

Note 3: Peak switch current is the guaranteed minimum value of switch

current available in normal operation. Highest calculated switch current at

full load should not exceed the minimum value shown.

Note 4: Loading on FB pin will affect NFB reference voltage.

Do not exceed 10

µA loading on FB when NFB is being used.

Note 5: This is the delay between sense pin current reaching its upper or

lower threshold and switch transition. Switch delay times cause peak-to-

peak inductor current to increase and therefore switching frequency to be

low. This effect will be significant for frequencies above 100kHz. See

Application Information and Typical Performance Characteristics.

all loads and full temperature range.

Note 7: As with all boost regulators the output voltage of the LT1500

cannot fall to less than input voltage because of the path through the catch

diode. This means that the output voltage divider on adjustable parts will

still be generating feedback voltage at the FB pin (fixed voltage parts have

an internal switch to disconnect the divider in shutdown). If the voltage on

FB is greater than 0.6V in shutdown, the internal error amplifier will draw

current that adds to shutdown current. See graph of Shutdown Current vs

FB voltage in Typical Performance Characteristics.

Switching Frequency

(3.3V Output)

LOAD CURRENT (mA)

0

50

100

10

100

1000

150

200

250

300

LTC1500/01 • TPC20

10

µH

20

µH

50

µH

100

µH

BURST REGION

VIN = 2.3V

Switching Frequency (5V Output)

LOAD CURRENT (mA)

0

50

100

10

100

1000

150

200

250

300

LTC1500/01 • TPC21

10

µH

20

µH

50

µH

100

µH

BURST REGION

VIN = 3V

Switching Frequency (12V Output)

LOAD CURRENT (mA)

025

50

75

1000

100

10

100 125 150 175

200

LTC1500/01 • TPC22

10

µH

50

µH

20

µH

100

µH

BURST REGION

VIN = 5V

Efficiency (3.3V Output)

LOAD CURRENT (mA)

1

100

90

80

70

60

50

40

30

10

100

1000

LTC1500/01 • TPC17

LOW LOSS INDUCTOR

L = 100

µH

L = 10

µH

L = 33

µH

Efficiency (5V Output)

LOAD CURRENT (mA)

1

100

90

80

70

60

50

40

30

10

100

1000

LTC1500/01 • TPC18

LOW LOSS INDUCTOR

L = 100

µH

L = 10

µH

L = 33

µH

Efficiency (12V Output)

LOAD CURRENT (mA)

1

100

90

80

70

60

50

40

30

10

100

1000

LTC1500/01 • TPC19

LOW LOSS INDUCTOR

L = 100

µH

L = 10

µH

L = 33

µH