Datasheet
MAX1927/MAX1928
Low-Output-Voltage, 800mA, PWM Step-Down
DC-DC Converters
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
BATT
= 3.6V, SHDN = BATT, C
REF
= 0.1µF, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
BATT, PWM, POK, COMP, SHDN to GND ...............-0.3V to +6V
PGND to GND .......................................................-0.3V to +0.3V
LX, REF, FB to GND ................................-0.3V to (V
BATT
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
BATT Input Voltage 2.6 5.5 V
Undervoltage Lockout Threshold V
BATT
rising or falling (35mV hysteresis)
2.15 2.35
2.55
V
No load, pulse skipping, PWM = GND
140
240 µA
Quiescent Current
1MHz switching 2 mA
Quiescent Current in Dropout
190
340 µA
Shutdown Supply Current SHDN = GND 0.1 10 µA
REFERENCE AND ERROR AMP
MAX1927R
0.738 0.75 0.762
MAX1928-15
1.477
1.5
1.523
MAX1928-18
1.773
1.8
1.827
FB Voltage Accuracy
MAX1928-25
2.462
2.5
2.538
V
MAX1928 5 10 15 µA
FB Input Current
MAX1927R 10 150 nA
MAX1927R
250
MAX1928-15
210
MAX1928-18
175
Transconductance (g
m
)
MAX1928-25
125
µS
Reference Voltage Accuracy
1.231 1.25 1.269
V
Reference Supply Rejection 2.6V < V
BATT
< 5.5V 0.5 2 mV
PWM CONTROLLER
V
BATT
= 3.6V
0.25
0.4
P-Channel On-Resistance
V
BATT
= 2.6V 0.3 0.5
Ω
V
BATT
= 3.6V
0.17
0.3
N-Channel On-Resistance
V
BATT
= 2.6V 0.2
0.35
Ω
Current-Sense Transresistance (R
CS
)
0.48
V/A
P-Channel Current-Limit Threshold 1.1 1.3 1.6 A
P-Channel Pulse-Skipping Current Threshold
0.11 0.13 0.15
A
N-Channel Negative Current-Limit Threshold
-0.55
A