MAX8537/MAX8538/MAX8539
Dual-Synchronous Buck Controllers for Point-of-
Load, Tracking, and DDR Memory Power Supplies
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 12V, EN_ = VL, BST_ = 6V, LX_ = 1V, VL load = 0mA, C
VL
= 10µF (ceramic), REFIN = 1.25V, PGND = AGND = FB_ = ILIM_ =
0V, C
SS
= 10nF, C
VTTR
= 1µF, R
FREQ
= 20kΩ, DH_ = open, DL_ = open, POK_ = open, circuit of Figure 1, T
A
= 0°C to +85°C, unless
otherwise noted.)
PARAMETER CONDITIONS MIN TYP MAX UNITS
REFIN Input Voltage Range 0.5 2.5 V
REFIN Undervoltage-Lockout Trip
Level
Rising and falling edge, hysteresis = 15mV 0.4 0.45 0.5 V
OUTPUT-VOLTAGE FAULT COMPARATORS
Upper FB2 Fault Threshold Rising voltage, hysteresis = 15mV 115 117 120
% of
REFIN
Lower FB2 Fault Threshold Falling voltage, hysteresis = 15mV 68 70 72
% of
REFIN
Upper FB1 Fault Threshold Rising voltage, hysteresis = 15mV 115 117 120
% of
0.8V
Lower FB1 Fault Threshold Falling voltage, hysteresis = 15mV 68 70 72
% of
0.8V
POWER-OK OUTPUT (POK_)
POK_ Delay 64
Clock
cycles
Upper FB2 POK_ Threshold Rising voltage, hysteresis = 20mV 110 112 114
% of
REFIN
Lower FB2 POK_ Threshold Falling voltage, hysteresis = 20mV 86 88 90
% of
REFIN
Upper FB1 POK_ Threshold Rising voltage, hysteresis = 20mV 110 112 114
% of
0.8V
Lower FB1 POK_ Threshold Falling voltage, hysteresis = 20mV 86 88 90
% of
0.8V
POK_ Output Low Level I
SINK
= 2mA 0.4 V
POK_ Output High Leakage POK_ = 5.5V 1 µA
ELECTRICAL CHARACTERISTICS (Note 2)
(V+ = 12V, EN_ = VL, BST_ = 6V, LX_ = 1V, VL load = 0mA, C
VL
= 10µF (ceramic), REFIN = 1.25V, PGND = AGND = FB_ = ILIM_ =
0V, C
SS
= 10nF, C
VTTR
= 1µF, R
FREQ
= 20kΩ, DH_ = open, DL_ = open, POK_ = open, circuit of Figure 1, T
A
= -40°C to +85°C,
unless otherwise noted.)
PARAMETER CONDITIONS MIN TYP MAX UNITS
V+ Operating Range VL regulator drops out below 5.5V (Note 1) 4.75 23.00 V
FB_ Input-Voltage Set Point Over line and load 0.788 0.800 0.812 V
FB2 Input-Voltage Set Point MAX8537/MAX8539, REFIN = 0.9V 0.891 0.900 0.909 V
VTTR Output Accuracy -15mA < I
VTTR
≤ +15mA, REFIN = 0.9V or 1.25V -1 REFIN +1 %
Note 1: Operating supply range is guaranteed by the VL line-regulation test. User must short V+ to VL if a fixed 5V supply is used
(i.e., if V+ is less than 5.5V).
Note 2: Specifications to -40°C are guaranteed by design, not production tested.
