Rainbow-electronics MAX1821 Manual de usuario descargar pdf (Pagina 3)

MAX1820/MAX1821

WCDMA Cellular Phone 600mA

Buck Regulators

_______________________________________________________________________________________ 3

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CONTROLLER

I

LX

= 180mA, V

BATT

= 3.6V 0.15 0.3

P-Channel On-Resistance P

RDS

I

LX

= 180mA, V

BATT

= 2.6V 0.2

Ω

I

LX

= 180mA, V

BATT

= 3.6V 0.2 0.35

N-Channel On-Resistance N

RDS

I

LX

= 180mA, V

BATT

= 2.6V 0.3

Ω

Current-Sense Transresistance R

CS

0.25 0.50 0.75 V/A

P-Channel Current-Limit

Threshold

Duty factor = 100% 0.75 1.2 1.55 A

P-Channel Pulse-Skipping

Current Threshold

SKIP = GND 0.04 0.13 0.24 A

SKIP = BATT -1.6 -0.85 -0.45

N-Channel Current-Limit

Threshold

SKIP = GND 0.02 0.08 0.14

A

LX Leakage Current I

LX

V

BATT

= 5.5V, LX = GND or BATT -1 0.1 1 µA

Maximum Duty Cycle duty

MAX

100 %

SKIP = GND 0

Minimum Duty Cycle duty

MIN

SKIP = BATT, V

BATT

= 4.2V

P-P

10

%

SYNC AND OSCILLATOR

S Y N C = si ne w ave, S Y N C i np ut = 200m V

P-P

13 13

SYNC Divide Ratio

(MAX1820X)

S Y N C = si ne w ave, S Y N C i np ut = 800m V

P-P

13 13

Hz/Hz

SYNC Capture Range

(MAX1820X)

SYNC = sine wave, AC-coupled,

SYNC input = 500mV

P-P

10 13 16 MHz

V

SYNC

= 1V (MAX1820Z, MAX1821) -1 +1

SYNC Leakage Current

Frequency

I

SYNC

V

SYNC

= 1V (MAX1820X, MAX1820Y, and

MAX1821X)

-5 +5

µA

S Y N C = si ne w ave, S Y N C i np ut = 200m V

P-P

18 18

SYNC Divide Ratio

(MAX1820Y)

S Y N C = si ne w ave, S Y N C i np ut = 800m V

P-P

18 18

Hz/Hz

SYNC Capture Range

(MAX1820Y)

SYNC = sine wave, AC-coupled,

SYNC input = 500mV

P-P

15 19.8 21 MHz

Internal Oscillator Frequency

(MAX1820Z, MAX1821)

f

OSC

SYNC = GND 0.8 1 1.2 MHz

LOGIC INPUTS (SKIP, SHDN)

Logic Input High V

IH

1.6 V

Logic Input Low V

IL

0.4 V

Logic Input Current -1 0.1 1 µA

ELECTRICAL CHARACTERISTICS (continued)

(V

BATT

= 3.6V, SHDN = BATT, SKIP = SYNC = GND, V

REF

= 1.25V (MAX1820 only), T

A

= 0°C to +85°C, unless otherwise noted.

Typical values are at T

A

= +25°C.) (Note 2)

1 2 3 4 5 6 7 8 ... 17 18

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