Datasheet

MAX8650
4.5V to 28V Input Current-Mode Step-Down
Controller with Adjustable Frequency
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 12V, V
BST
- V
LX
= 6.5V, T
A
= -40°C to +85°C. Typical values are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER CONDITIONS MIN TYP MAX UNITS
ERROR AMPLIFIER
REFIN = AVL 0.693 0.7 0.707
FB Regulation Voltage
V
REFIN
= 0.7V to 1.5V
V
REFIN
-
0.00375
V
REFIN
V
REFIN
+
0.00375
V
Transconductance 70 110 160 µS
COMP Shutdown Resistance From COMP to GND, V
EN
= 0V 20 100 Ω
FB Input Leakage Current V
FB
= 0.7V 5 50 nA
FB Input Common-Mode Range -0.1 +1.5 V
CURRENT-SENSE AMPLIFIER
Voltage Gain V
OUT
= 0 to 5.5V, V
CS+
- V
CS-
= 30mV 12 V/V
CURRENT LIMIT
R
ILIM1
= 24kΩ 27.2 32.0 36.8
Peak Current-Limit
Threshold (V
CS+
- V
CS-
)
ILIM1 = AVL 68.0 80.0 92.0
mV
R
ILIM2
= 50kΩ -42.5 -50.0 -57.5
Valley Current-Limit Threshold
(V
LX
- V
PGND
)
R
ILIM2
= 200kΩ -170 -200 -230
mV
Negative Current-Limit Threshold % of (typ) positive direction current limit (V
LX
- V
PGND
) -90 -120 -150 %
CS+, CS- Input Current V
CS+
= V
CS-
= 0V or 5.5V -25 +25 µA
CS+, CS- Input Common-Mode
Range
0 5.5 V
SLOPE COMPENSATION
V
SCOMP
= 2.5V 231.25 250.00 268.75
V
SCOMP
= 1.25V 113.77 123.00 132.23
SCOMP = AVL 231.25 250.00 268.75
SCOMP = GND, T
A
= 0°C to +85°C 113.77 123.00 132.23
Slope Compensation at Maximum
Duty Cycle
T
A
= -40°C to +85°C 110.70 123.00 132.23
mV
SCOMP High Threshold V
AVL
- 0.5 V
SCOMP Low Threshold 0.5 V
SCOMP Adjustment Range 1.25 2.5 V
SCOMP Input Leakage Current V
SCOMP
= 1.25V to 2.5V 5 200 nA
OSCILLATOR
R
FSYNC
= 21.0kΩ 800 1000 1200
Switching Frequency
R
FSYNC
= 143kΩ 160 200 240
kHz
Minimum Off-Time Measured at DH 235 ns
Minimum On-Time Measured at DH 75 100 ns