Datasheet

MAX1533A/MAX1537A
High-Efficiency, 5x Output, Main Power-Supply
Controllers for Notebook Computers
_______________________________________________________________________________________ 7
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
FSEL = GND
170
230
FSEL = REF
240
330Operating Frequency (Note 1) f
OSC
FSEL = V
CC
375
575
kHz
FSEL = GND 91
FSEL = REF 91
Maximum Duty Factor (Note 1) D
MAX
FSEL = V
CC
91
%
Minimum On-Time
t
ON
(
MIN
)
250 ns
CURRENT LIMIT
ILIM_ Adjustment Range 0.5
V
REF
V
Current-Limit Threshold (Fixed)
V
LIMIT
_
V
CSH
_ - V
CSL
_ , ILIM_ = V
CC
67 83 mV
V
ILIM
_ = 2.00V
170
230
V
ILIM
_ = 1.00V 90 110
Current-Limit Threshold
(Adjustable)
V
LIMIT
_
V
CSH
_ - V
CSL
_
V
ILIM
_ = 0.50V 40 60
mV
INTERNAL FIXED LINEAR REGULATORS
LDO5 Output Voltage V
LDO5
ON3 = ON5 = GND, 6V < V
IN
< 26V,
0 < I
LDO5
< 100mA
4.8 5.1 V
LDO5 Undervoltage-Lockout
Fault Threshold
Rising edge, hysteresis = 1%
3.75 4.30
V
LDO3 Output Voltage V
LDO3
Standby mode, 6V < V
IN
< 28V,
0 < I
LOAD
< 100mA
3.20 3.43
V
AUXILIARY LINEAR REGULATOR (MAX1537A ONLY)
LDOA Voltage Range V
LODA
523V
INA Voltage Range V
INA
624V
LDOA Regulation Threshold,
Internal Feedback
ADJA = GND, 0 < I
LDOA
< 120mA,
V
INA
> 13V
11.40 12.55
V
ADJA Regulation Threshold,
External Feedback
V
ADJA
0 < I
LDOA
< 120mA, V
LDOA
> 5.0V and
V
INA
> V
LDOA
+ 1V
1.94 2.08
V
ADJA Dual-Mode Threshold ADJA
0.10 0.25
V
Secondary Feedback
Regulation Threshold
V
INA
- V
LDOA
0.63 0.97
V
INA Quiescent Current I
INA
V
INA
= 24V, I
LDOA
= no load 165 µA
REFERENCE (REF)
Reference Voltage V
REF
V
CC
= 4.5V to 5.5V, I
REF
= 0
1.97 2.03
V