Datasheet

MAX8792
Single Quick-PWM Step-Down
Controller with Dynamic REFIN
_______________________________________________________________________________________ 3
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
FAULT DETECTION
With respect to the internal target voltage
(error comparator threshold); rising edge;
hysteresis = 50mV
250 300 350 mV
Dynamic transition
V
REF
+
0.30
Output Overvoltage-Protection
Trip Threshold
OVP
Minimum OVP threshold 0.7
V
Output Overvoltage
Fault-Propagation Delay
t
OVP
FB forced 25mV above trip threshold 5 μs
Output Undervoltage-Protection
Trip Threshold
UVP
With respect to the internal target voltage
(error comparator threshold); falling edge;
hysteresis = 50mV
-240 -200 -160 mV
Output Undervoltage
Fault-Propagation Delay
t
UVP
FB forced 25mV below trip threshold 100 200 350 μs
UVP falling edge, 25mV overdrive 5
OVP rising edge, 25mV overdrive 5
PGOOD Propagation Delay t
PGOOD
Startup delay 100 200 350
μs
PGOOD Output-Low Voltage I
SINK
= 3mA 0.4 V
PGOOD Leakage Current I
PGOOD
FB = REFIN (PGOOD high impedance),
PGOOD forced to 5V, T
A
= +25°C
1μA
Dynamic REFIN Transition Fault
Blanking Threshold
Fault blanking initiated; REFIN deviation
from the internal target voltage (error
comparator threshold); hysteresis = 10mV
±50 mV
Thermal-Shutdown Threshold T
SHDN
Hysteresis = 15°C 160 °C
V
CC
Undervoltage Lockout
Threshold
V
U V LO
(
V C C
)
Rising edge, PWM disabled below this
level; hysteresis = 100mV
3.95 4.2 4.45 V
CURRENT LIMIT
ILIM Input Range 0.4 V
REF
V
V
ILIM
= 0.4V 18 20 22
Current-Limit Threshold V
ILIMIT
ILIM = REF (2.0V) 92 100 108
mV
Current-Limit Threshold
(Negative)
V
INEG
V
ILIM
= 0.4V -24 mV
Current-Limit Threshold
(Zero Crossing)
V
ZX
V
ILIM
= 0.4V,
V
GND
- V
LX
, SKIP = GND or open
1mV
Ultrasonic Frequency SKIP = open (3.3V); V
FB
= V
REFIN
+ 50mV 18 30 kHz
U l tr asoni c C ur r ent- Li m i t Thr eshol d SKIP = open (3.3V); V
FB
= V
REFIN
+ 50mV 35 mV
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= 12V, V
DD
= V
CC
= V
EN
= 5V, REFIN = ILIM = REF, SKIP = GND. T
A
= 0°C to +85°C, unless otherwise spec-
ified. Typical values are at T
A
= +25°C.) (Note 1)