Datasheet

MAX8543/MAX8544
Step-Down Controllers with Prebias Startup,
Lossless Sensing, Synchronization, and OVP
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 13.2V, V
BST
- V
LX
= 5V, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
V
CS+
- V
CS-
, V
ILIM1
= 0V
38.5
50
56.5
V
CS+
- V
CS-
, V
ILIM1
= (1/3)V
VL
85
100 115
V
CS+
- V
CS-
, V
ILIM1
= (2/3)V
VL
127.5 150 172.5
V
CS+
- V
CS-
, V
ILIM1
= V
VL
170 200 230
V
LX
- V
PGND
, R
ILIM2
= 50kΩ (MAX8544 only)
-42.5
-50
-57.5
V
LX
- V
PGND
, R
ILIM2
= 200kΩ (MAX8544 only)
-160 -200 -240
V
LX
- V
PGND
, V
FB
= 0.8V (MAX8543 only)
-110 -130 -150
Current-Limit Threshold
V
LX
- V
PGND
, V
FB
= 0V (MAX8543 only) -20 -30 -40
mV
Negative Current-Limit Threshold % of positive-direction current limit V
LX
- V
PGND
-25 -50 -85 %
CS+, CS- Input Current V
CS+
= V
CS-
= 0 or 5V -40
+40
µA
CS+, CS- Input Common-Mode Range 0
13.2
V
OSCILLATOR
R
FSYNC
= 18.2kΩ
800 1000 1200
Switching Frequency
R
FSYNC
= 158kΩ
200
kHz
Minimum Off-Time Measured at DH
150 220 270
ns
Minimum On-Time Measured at DH 90
145
ns
FSYNC Synchronization Range
160 1200
kHz
FSYNC Input High Pulse Width
100
ns
FSYNC Input Low Pulse Width
100
ns
FSYNC Rise/Fall Time
100
ns
SYNCO Phase Shift from DH Rising
R
FSYNC
= 18.2kΩ, free-running mode,
at maximum duty cycle
165 180 195
Degrees
SYNCO Output Low Level I
SYNCO
= 5mA 0.4 V
SYNCO Output High Level I
SYNCO
= 5mA
V
VL
- 1V
V
MOSFET DRIVERS
(V
BST
- V
LX
) = 5V 1 2.5
DH On-Resistance, High State
(V
BST
- V
LX
) = 3V 1.2
Ω
(V
BST
- V
LX
) = 5V 1 2.5
DH On-Resistance, Low State
(V
BST
- V
LX
) = 3V 1.2
Ω
V
VL
= 5V 1 2.5
DL On-Resistance, High State
V
VL
= 3V 1.2
Ω
V
VL
= 5V 0.6 1.7
DL On-Resistance, Low State
V
VL
= 3V 0.8
Ω
Low-side off to high-side on 55
Break-Before-Make Dead Time
High-side off to low-side on 40
ns
LX, BST, IN Leakage Current V
BST
= 18.7V, V
LX
= 13.2V, V
IN
= 13.2V 5 µA
THERMAL PROTECTION
Thermal Shutdown Rising temperature
+160
°C
Thermal-Shutdown Hysteresis 15 °C