MAX849 查看數據表（PDF） - Maxim Integrated

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产品描述 (功能)

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MAX849

1-Cell to 3-Cell, High-Power, Low-Noise, Step-Up DC-DC Converters

Maxim Integrated 

1-Cell to 3-Cell, High-Power,

Low-Noise, Step-Up DC-DC Converters

ELECTRICAL CHARACTERISTICS

(VOUT = 3.6V, GND = PGND = CLK/SEL = ON1 = ON2 = AINSEL = AIN1 = AIN2 = FB = POKIN, POUT = OUT, TA = -40°C to +85°C,

unless otherwise noted.) (Note 9)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

REFERENCE

Reference Output Voltage

DC-DC CONVERTER

IREF = 0mA

1.225

1.275

V

Output Voltage (Note 3)

VFB < 0.1V, CLK/SEL = OUT,

includes load-regulation error

3.13

3.47

V

FB Regulation Voltage

Adjustable output, CLK/SEL = OUT

1.21

1.27

V

Output Voltage Lockout Range

OUT Supply Current in Shutdown

OUT Supply Current in Low-Power

Mode (Note 6)

(Note 3)

V ON2 = 3.6V

CLK/SEL = GND

2.05

2.45

V

20

µA

90

µA

OUT Supply Current in Low-Noise

Mode (Note 6)

CLK/SEL = OUT, does not include

switching losses

300

µA

DC-DC SWITCHES

Switch On-Resistance

N-Channel Current Limit

ADC

Accuracy

POWER-GOOD

Internal Trip Level

External Trip Level

LOGIC CONTROL INPUTS

Internal Oscillator Frequency

Oscillator Maximum Duty Cycle

N-channel

CLK/SEL = GND

CLK/SEL = OUT

P-channel

CLK/SEL = OUT

CLK/SEL = OUT

MAX848

MAX849

MAX848

CLK/SEL = GND (Note 7)

MAX849

600

1100

120

250

fCLK = 400kHz, 5ms conversion

Rising VOUT, VPOKIN < 0.1V

Rising VPOKIN

2.95

1.225

CLK/SEL = OUT

260

80

0.6

0.25

0.5

1100

1800

300

550

±4

3.10

1.275

340

90

Ω

mA

% FSR

V

V

kHz

%

Note 1: Minimum operating voltage. Because the MAX848/MAX849 are bootstrapped to the output, it will operate down to a 0.7V input.

Note 2: In low-power mode (CLK/SEL = GND), the output voltage regulates 1% higher than in low-noise mode (CLK/SEL = OUT or

synchronized).

Note 3: The part is in start-up mode until it reaches this voltage level. Do not apply full-load current.

Note 4: Load regulation is measured from no load to full load, where full load is determined by the N-channel switch current limit.

Note 5: Start-up is tested with Figure 2’s circuit. Output current is measured when the input and output voltages are applied.

Note 6: Supply current from the 3.34V output is measured between the 3.34V output and the OUT pin. This current correlates directly

with actual battery supply current, but is reduced in value according to the step-up ratio and efficiency. VOUT = 3.6V to keep

the internal switch open when measuring the current into the device.

Note 7: When VCLK/SEL = 0V, the inductor is forced into constant-peak-current, discontinuous operation. This is guaranteed by

testing in Figure 2’s circuit.

Note 8: ON1 and ON2 inputs have approximately 0.15VOUT hysteresis.

Note 9: Specifications to -40°C are guaranteed by design, not production tested.

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