Datasheet

MAX8543/MAX8544
Step-Down Controllers with Prebias Startup,
Lossless Sensing, Synchronization, and OVP
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 13.2V, 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
V
ILIM1
= 0V 8.8
13.2
V
ILIM1
= (1/3)V
VL
4.8 7.2
V
ILIM1
= (2/3)V
VL
3.2 4.8
Voltage Gain V
OUT
= 0 to 13V
V
ILIM1
= V
VL
2.4 3.6
V / V
CURRENT LIMIT
ILIM2 Output Current (MAX8544 Only) R
ILIM2
= 50kΩ to 200kΩ 4.2 5.5 µA
ILIM1 Input Current V
ILIM1
= 0V or V
VL
-1 +1 µA
V
CS+
- V
CS-
, V
ILIM1
= 0V
38.5 56.5
V
CS+
- V
CS-
, V
ILIM1
= (1/3)V
VL
85 115
V
CS+
- V
CS-
, V
ILIM1
= (2/3)V
VL
127.5 172.5
V
CS+
- V
CS-
, V
ILIM1
= V
VL
170
230
V
LX
- V
PGND
, R
ILIM2
= 50kΩ (MAX8544 only) -40 -60
V
LX
- V
PGND
, R
ILIM2
= 200kΩ (MAX8544 only)
-160 -240
V
LX
- V
PGND
, V
FB
= 0.8V (MAX8543 only)
-110 -150
Current-Limit Threshold
V
LX
- V
PGND
, V
FB
= 0V (MAX8543 only) -20 -40
mV
Negative Current-Limit Threshold % of positive-direction current limit V
LX
- V
PGND
-25 -85 %
CS+, CS- Input Current V
CS+
= V
CS-
= 0V or 5V -40
+40
µA
CS+, CS- Input Common-Mode Range 0
13.2
V
OSCILLATOR
Switching Frequency R
FSYNC
= 18.2kΩ
800 1200
kHz
Minimum Off-Time Measured at DH
150
270 ns
Minimum On-Time Measured at DH 140 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
165
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
DH On-Resistance, High State (V
BST
- V
LX
) = 5V 2.5 Ω
DH On-Resistance, Low State (V
BST
- V
LX
) = 5V 2.5 Ω
DL On-Resistance, High State V
VL
= 5V 2.5 Ω
DL On-Resistance, Low State V
VL
= 5V 1.7 Ω
LX, BST, IN Leakage Current V
BST
= 18.7V, V
LX
= 13.2V, V
IN
= 13.2V 5 µA