LT8355-1

3

Rev. A

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ELECTRICAL CHARACTERISTICS

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Internal Voltage Regulators

INTVCC Regulation Voltage

PWM1,2 = 0V, IINTVCC = 1mA, 12V < VIN < 60V

7.35

7.5

7.65

V

INTVCC Line Regulation

PWM1,2 = 0V, 10 < VIN < 60V

0.75

3

mV/V

INTVCC Load Regulation

PWM1,2 = 0V, 1mA < IINTVCC < 30mA

2.25

4.5

mV/mA

INTVCC Current Limit

PWM1,2 = 0V, VIN = 12V, INTVCC = 7V

PWM1,2 = 0V, VIN = 60V, INTVCC = 7V

110

30

140

45

170

60

mA

mA

INTVCC Dropout Voltage

PWM1,2 = 0V, VIN = 5V, ILOAD = 10mA

250

mV

INTVCC Undervoltage Lockout Threshold

PWM1,2 = 0V, INTVCC Falling

4.3

V

VREF Voltage

IVREF = 0.5mA

l

1.97

2

2.02

V

VREF Load Regulation

IVREF = 0.1mA to 1mA

5

8

mV/mA

VREF Current Limit

VREF = 1.8V

2.5

3.2

4.0

mA

Channel 1, Channel 2 Current Regulation (Note 5)

ISP, ISN Common Mode Voltage Range

l

0

110

V

LED Current Sense Threshold (VISP – VISN)

CTRL1,2 = 2V, IADJ2 = 2V (100%), ISP1,2 = 100V

CTRL1,2 = 1V, IADJ2 = 2V (50%), ISP1,2 = 100V

CTRL1,2 = 0.6V, IADJ2 = 2V (10%), ISP1,2 = 100V

CTRL1,2 = 2V, IADJ2 = 2V (100%), ISN1,2 = 0V

l

l

l

245

120

20

240

250

125

25

250

255

130

30

260

mV

mV

mV

mV

LED2 Current Sense Threshold (VISP2 – VISN2)

CTRL2 = 2V, IADJ2 = 1V (50%), ISP = 100V

l

118

125

134

mV

SENSE Current Limit Threshold

(SENSEP − SENSEN)

50% Duty Cycle at GATE (Note 6)

l

95

108

120

mV

CTRL Off Threshold (Falling)

l

285

310

335

mV

IADJ2 Off Threshold (Falling)

500

mV

CTRL Off Hysteresis

30

mV

IADJ2 Off Hysteresis

20

mV

CTRL Pin Current

Current Out of Pin, CTRL1,2 = 0

20

nA

IADJ2 Pin Current

IADJ2 = 1.5V

0

nA

ISP, ISN Pin Current (Combined)

PWM1,2 = INTVCC, ISP1,2 = 100V (Active)

PWM1,2 = 0V, ISP1,2 = 100V (Standby)

600

20

25

µA

µA

Error Amp Transconductance

CTRL1,2 = 2V, IADJ2 = 2V (Full-Scale)

65

µS

Error Amp Output Resistance

15

MΩ

Channel 1, Channel 2 Output Voltage Regulation

FB Regulation Voltage (VFB)

CTRL1,2 = 2V, IADJ2 = 2V

CTRL1,2 = 2V, IADJ2 = 2V

l

1.182

1.176

1.2

1.2

1.218

1.224

V

V

FB Pin Current

Current Out of Pin, VFB1,2 = 1.18V

20

nA

FB Amplifier Transconductance

380

µS

Oscillator

Programmed Switching Frequency (fSW1, Channel 1) RT = 9.09kΩ

RT = 51.1kΩ

RT = 215kΩ

l

1800

380

96

1950

400

102

2100

420

108

kHz

kHz

kHz

Channel Frequency Difference (fSW2 – fSW1)

RT = 51.1kΩ

4.5

%fSW1

Spread Spectrum Frequency Range

100

126

%fSW

Minimum Off-Time

RT = 9.09kΩ

RT = 51.1kΩ

RT = 215kΩ

l

l

l

30

75

100

60

120

170

85

165

240

ns

ns

ns

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. (Note 2). Unless otherwise noted, VIN = EN/UVLO = 12V, ISP1,2 =

ISN1,2 = 60V, CTRL1,2 = IADJ2 = 2V, PWM1,2 = INTVCC, FB1,2 = 1V, SENSEN1,2 = 0V.