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

Low-Noise, Step-Up DC-DC Converters

4

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ELECTRICAL CHARACTERISTICS

unless otherwise noted.) (Note 9)

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

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

testing in Figure 2’s circuit.

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

%

80

90

Oscillator Maximum Duty Cycle

kHz

260

340

CLK/SEL = OUT

Internal Oscillator Frequency

V

1.225

1.275

External Trip Level

V

2.95

3.10

Internal Trip Level

% FSR

±4

Accuracy

250

550

MAX849

CLK/SEL = GND (Note 7)

N-Channel Current Limit

120

300

MAX848

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

1100

1800

MAX849

CLK/SEL = OUT

mA

600

1100

MAX848

0.5

CLK/SEL = OUT

P-channel

Switch On-Resistance

0.25

CLK/SEL = OUT

N-channel

Reference Output Voltage

1.225

1.275

V

Ω

Output Voltage (Note 3)

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

(Note 3)

2.05

2.45

V

0.6

CLK/SEL = GND

µA

300

CLK/SEL = OUT, does not include

switching losses

OUT Supply Current in Low-Noise

Mode (Note 6)

µA

90

CLK/SEL = GND

OUT Supply Current in Low-Power

Mode (Note 6)

OUT Supply Current in Shutdown

20

µA

REFERENCE

DC-DC CONVERTER

DC-DC SWITCHES

ADC

POWER-GOOD

LOGIC CONTROL INPUTS