Datasheet

MAX1533A/MAX1537A
High-Efficiency, 5x Output, Main Power-Supply
Controllers for Notebook Computers
8 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= 12V, both SMPS enabled, V
CC
= 5V, FSEL = REF, SKIP = GND, V
ILIM_
= V
LDO5
, V
INA
= 15V, V
LDOA
= 12V,
I
LDO5
= I
LDO3
= I
LDOA
= no load, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 4)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX
UNITS
FAULT DETECTION
Output Overvoltage Trip
Threshold
OVP = GND, with respect to error-
comparator threshold
+8
+15
%
Output Undervoltage-Protection
Trip Threshold
With respect to error-comparator threshold +65 +75
%
PGOOD Lower Trip Threshold
With respect to error-comparator threshold,
hysteresis = 1%
-14.0 -7.0
%
PGOOD Output Low Voltage I
SINK
= 4mA 0.4 V
PGDLY Pulldown Resistance 25 Ω
PGDLY Trip Threshold
REF-
0.2
REF+
0.2
V
GATE DRIVERS
DH_ Gate-Driver On-Resistance R
DH
BST_ - LX_ forced to 5V 5 Ω
DL_, high state 5
DL_ Gate-Driver On-Resistance R
DL
DL_, low state 3
Ω
INPUTS AND OUTPUTS
High 2.4
Logic Input Voltage SKIP, hysteresis = 600mV
Low 0.8
V
High
0.7 x
V
CCFault Enable Logic Input Voltage
OVP, UVP, ONA
Low 0.4
V
Rising trip level 1.1 2.2
SHDN Input Trip Level
Falling trip level
0.95 1.05
V
Clear fault level 0.8
SMPS off level 1.6
Delay start level (REF) 1.9 2.1
ON_ Input Voltage
SMPS on level 2.4
V
High V
CC
- 0.2
REF 1.7 2.3FSEL Three-Level Input Logic
GND 0.4
V
Note 1: The MAX1533A/MAX1537A cannot operate over all combinations of frequency, input voltage (V
IN
), and output voltage. For
large input-to-output differentials and high-switching frequency settings, the required on-time may be too short to maintain
the regulation specifications. Under these conditions, a lower operating frequency must be selected. The minimum on-time
must be greater than 150ns, regardless of the selected switching frequency. On-time and off-time specifications are mea-
sured from 50% point to 50% point at the DH_ pin with LX_ = GND, V
BST_
= 5V, and a 250pF capacitor connected from DH_
to LX_. Actual in-circuit times may differ due to MOSFET switching speeds.
Note 2: When the inductor is in continuous conduction, the output voltage has a DC regulation level lower than the error-comparator
threshold by 50% of the ripple. In discontinuous conduction (SKIP = GND, light load), the output voltage has a DC regula-
tion level higher than the trip level by approximately 1% due to slope compensation.
Note 3: Specifications are guaranteed by design, not production tested.
Note 4: Specifications to -40°C are guaranteed by design, not production tested.