Rainbow Electronics MAX1821 - Manual (Page 3)

MAX1820/MAX1821
WCDMA Cellular Phone 600mA
Buck Regulators
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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)