Datasheet

MAX1954A
Low-Cost, Current-Mode PWM Buck
Controller with Foldback Current Limit
4 _______________________________________________________________________________________
Note 1: HSD and IN are externally connected for applications where HSD < 5.5V.
Note 2: Specifications to -40°C are guaranteed by design and not production tested.
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 5V, V
BST
- V
LX
= 5V, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 2)
PARAMETER CONDITIONS
MIN MAX
UNITS
Current-Sense Amplifier
Voltage Gain
3.15 3.85
V/V
V
FB
= 0.8V
110 145
Current-Limit Threshold V
PGND
- V
LX
, MAX1954A
V
FB
= 0V 21 51
mV
OSCILLATOR
Switching Frequency
240 360
kHz
Maximum Duty Cycle Measured at DH 89 93 %
Minimum Duty Cycle V
COMP
= 1.25V, LX = GND, V
BST
= V
IN
= 3.3V 3 %
FET DRIVERS
DH, DL Output Low Voltage I
SINK
= 10mA 0.1 V
DH, DL Output High Voltage I
SOURCE
= 10mA
V
IN
- 0.1V or
V
BS T
- 0.1V
V
DH Pullup/Pulldown,
DL Pullup On-Resistance
3 Ω
DL Pulldown On-Resistance 2 Ω
LX, BST, HSD Leakage Current V
BST
= 18.7V, V
LX
= 13.2V, V
IN
= 5.5V, V
HSD
= 13.2V 30 µA
SHUTDOWN CONTROL
COMP Logic-Level Low 3V < V
IN
< 5.5V
0.25
V
COMP Logic-Level High 3V < V
IN
< 5.5V 0.8 V
COMP Pullup Current
100
µA