Datasheet

MAX8597/MAX8598/MAX8599
Low-Dropout, Wide-Input-Voltage,
Step-Down Controllers
6 _______________________________________________________________________________________
Note 1: Limits to -40°C are guaranteed by design and characterization.
ELECTRICAL CHARACTERISTICS (continued)
(V
V+
= V
VL
= V
AVL
= V
EN
= V
REFIN
= 5V, V
BST
= 6V, V
LX
= 1V, C
VL
= 4.7µF, C
REFOUT
= 1µF, V
AIN-
= V
AOUT
, V
AIN+
= 2.5V, V
ILIM
=
V
LX
- 0.2V, V
FB
= 0.65V, GND = PGND = 0V, C
SS
= 0.01µF, R
FREQ
= 20kΩ, 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
OV AND UV FAULT COMPARATORS
Upper FB Fault Threshold (OV) Rising edge, hysteresis = 15mV (MAX8599 only) 115 120 %
Lower FB Fault Threshold (UV) Falling edge, hysteresis = 15mV 67 73 %
POWER-OK OUTPUT (POK) (MAX8598/MAX8599 only)
Lower FB POK Threshold FB falling, hysteresis = 20mV 85 90 %
POK Output Low Level I
SINK
= 2mA 0.4 V
POK Output High Leakage V
POK
= 5.5V
5
µA
EFFICIENCY vs. LOAD CURRENT
CIRCUIT OF FIGURE 1
MAX8597 toc01
LOAD CURRENT (A)
EFFICIENCY (%)
1
65
70
75
80
85
90
95
100
60
0.1 10
V
OUT
= 11.5V
V
OUT
= 9V
V
OUT
= 6V
EFFICIENCY vs. LOAD CURRENT
CIRCUIT OF FIGURE 2
MAX8597 toc02
LOAD CURRENT (A)
EFFICIENCY (%)
10
40
50
60
70
80
90
100
30
1100
V
OUT
= 3.3V
V
OUT
= 2.5V
V
OUT
= 1.8V
V
OUT
= 1.2V
OUTPUT VOLTAGE
vs. LOAD CURRENT
MAX8597 toc03
I
LOAD
(A)
OUTPUT VOLTAGE (V)
18161412108642
1.195
1.200
1.205
1.210
1.190
020
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
MAX8597 toc04
V
IN
(V)
OUTPUT VOLTAGE (V)
13.513.012.512.011.511.010.5
1.195
1.200
1.205
1.210
1.190
10.0 14.0
I
LOAD
= 0A
I
LOAD
= 20A
POWER-UP WAVEFORMS
MAX8597 toc05
2ms/div
5V/div
V
AVL
I
LX
V
OUT
V
IN
10A/div
1V/div
10V/div
POWER-DOWN WAVEFORMS
MAX8597 toc06
2ms/div
5V/div
V
AVL
I
LX
I
OUT
V
IN
10A/div
1V/div
10V/div
Typical Operating Characteristics
(Circuit of Figure 4, T
A
= +25°C, 500kHz switching frequency, V
IN
= 12V, unless otherwise noted.)