Rainbow Electronics MAX1821 - Manual (Page 4)

MAX1820/MAX1821
WCDMA Cellular Phone 600mA
Buck Regulators
4 _______________________________________________________________________________________
PARAMETER SYMBOL CONDITIONS MIN MAX UNITS
Input BATT Voltage V IN 2.6 5.5 V
Undervoltage Lockout
Threshold
V UVLO V BATT rising, 1% hysteresis 2.15 2.55 V
SKIP = GND (MAX1820Z, MAX1821) 300
SKIP = GND (MAX1820X, MAX1820Y, and
MAX1821X)
360 Quiescent Current I
Q
SKIP = BATT, no switching 2000
µA
SKIP = GND 1000
Quiescent Current in Dropout
SKIP = BATT, no switching 1000
µA
Shutdown Supply Current I SHDN SHDN = GND 6 µA
ERROR AMPLIFIER
V REF = 1.932 ±0.005V, load = 0 to 600mA,
SKIP = BATT or GND
3.33 3.47
OUT Voltage Accuracy
(MAX1820)
V OUT
V REF = 0.227 ±0.005V, load = 0 to 30mA,
SKIP = BATT, V
BATT
≤ 4.2V
0.35 0.45
V
OUT Input Resistance
(MAX1820)
R OUT 250 k Ω
REF Input Current (MAX1820) I REF 1 µA
FB Voltage Accuracy
(MAX1821)
V FB FB = COMP 1.225 1.275 V
FB Input Current (MAX1821) I FB V FB = 1.4V 50 nA
Transconductance g m 30 85 µS
COMP Clamp Low Voltage 0.2 1.0 V
COMP Clamp High Voltage 2.04 2.28 V
CONTROLLER
P-Channel On-Resistance P RDS I LX = 180mA, V BATT = 3.6V 0.3 Ω
N-Channel On-Resistance N RDS I LX = 180mA, V BATT = 3.6V 0.35 Ω
Current-Sense Transresistance R CS 0.25 0.75 V/A
P-Channel Current-Limit
Threshold
Duty factor = 100% 0.75 1.55 A
P-Channel Pulse-Skipping
Current Threshold
SKIP = GND 0.04 0.24 A
SKIP = BATT -1.6 -0.45 N-Channel Current-Limit
Threshold
SKIP = GND 0.01 0.14
A
ELECTRICAL CHARACTERISTICS
(V BATT = 3.6V, SHDN = BATT, SKIP = SYNC = GND, V REF = 1.25V (MAX1820 only), T A = -40°C to +85°C, unless otherwise noted.)
(Notes 2, 3)