MAX1549ETL Datasheet, PDF (7/35 Pages) Maxim Integrated Products – Dual, Interleaved, Fixed-Frequency Step-Down Controller with a Dynamically Adjustable Output

Dual, Interleaved, Fixed-Frequency Step-Down
Controller with a Dynamically Adjustable Output
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V_CC = V_DD = 5V, SKIP = GND, T_A = -40°C to +85°C, unless otherwise noted.) (Note 4)
PARAMETER
INPUTS AND OUTPUTS
OD_ On-Resistance
ON_ Logic Input Threshold
Logic Input Voltage
Dual-Mode Threshold Voltage
Four-Level Input Logic Levels
SYMBOL
CONDITIONS
R_OD_
Rising edge, hysteresis = 600mV
SKIP, G0, G1, hysteresis =
600mV
High
Low
High
FB2
Low
High
FSEL, FBLANK
Open
REF
Low
MIN
2.4
2.4
1.9
0.05
V_CC - 0.4V
3.15
1.65
MAX UNITS
100
Ω
2.8
V
V
0.8
2.1
V
0.15
3.85
V
2.35
0.5
Note 1: 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 1.5% due to slope compensation.
Note 2: The MAX1549 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 measured from
the 50% point to the 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 3: Specifications are guaranteed by design, not production tested.
Note 4: Specifications to -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(MAX1549 circuit of Figure 1, V_IN = 12V, V_DD = V_CC = 5V, SKIP = GND, FSEL = open, T_A = +25°C, unless otherwise noted.)
OUT1 EFFICIENCY vs. LOAD CURRENT
(V_OUT1 = 1.0V)
100
SKIP = GND
SKIP = V_CC
90
80
70
60
50
0.01
V_IN = 5V
V_IN = 12V
V_IN = 20V
0.1
1
10
LOAD CURRENT (A)
1.0V OUTPUT VOLTAGE (OUT1)
vs. LOAD CURRENT
1.05
SKIP = GND
1.04 ^{SKIP = V}CC
1.03
1.02
1.01
1.00
0.99
0.98
01234567
LOAD CURRENT (A)
OUT2 EFFICIENCY vs. LOAD CURRENT
(V_OUT2 = 2.5V)
100
SKIP = GND
SKIP = V_CC
90
80
V_IN = 5V
70
V_IN = 12V
60
V_IN = 20V
50
0.01
0.1
1
10
LOAD CURRENT (A)
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