Datasheet

MAX8543/MAX8544
Step-Down Controllers with Prebias Startup,
Lossless Sensing, Synchronization, and OVP
10 ______________________________________________________________________________________
Pin Description
PIN
MAX8543
MAX8544
NAME FUNCTION
1 2 GND Ground. Connect to the analog ground plane.
23SS
Soft-Start. Connect a 0.1µF to 1µF ceramic capacitor from SS to GND. This capacitor
sets the soft-start period during startup. See the Startup and Soft-Start section. SS is
internally pulled to GND in shutdown.
3 4 COMP
Compensation. Connect to an external RC network to compensate the feedback loop.
See the Compensation Design section. COMP is internally pulled to GND in shutdown.
45FB
Output Feedback. Connect to the center of a voltage-divider connected between OUT
and GND to set the output voltage. The FB threshold voltage is 0.8V.
56EN
Enable. Drive EN logic high to enable the output, or drive logic low for shutdown.
Connect EN to IN for always-on operation.
6 7 CS- Negative Differential Current-Sensing Input
7 8 CS+ Positive Differential Current-Sensing Input
— 9 ILIM1
8 — ILIM
Digital Programmable Current-Limit Input for Inductor Current Sensing (V
CS+
- V
CS-
).
See Table 3.
9 12 PGND
Power Ground. Connect to the power ground plane and to the source of the low-side
external MOSFETs. Connect PGND to GND at a single point.
10 13 DL
Low-Side MOSFET Gate-Driver Output. Connect to the gate of the low-side external
MOSFETs. DL is pulled low in shutdown.
11 14 VL
Internal 5V Linear-Regulator Output. Connect a 1µF to 10µF ceramic capacitor from
VL to PGND. Connect VL to IN for V
IN
less than 5.5V. VL provides power for bias and
gate drive.
12 15 IN
Input Supply Voltage. IN is the input to the internal linear regulator. Connect VL to IN for
V
IN
less than 5.5V.
BODE PLOT, 600kHz, 15A LOAD
MAX8543 toc19
1kHz 1MHz100kHz10kHz
0dB
10dB/div
90
°
30
°
/div
SWEEP TIME
10.000s
BODE PLOT, 600kHz, NO LOAD
MAX8543 toc20
1kHz 1MHz100kHz10kHz
0dB
90
°
30
°
/div
SWEEP TIME
10.000s
10dB/div
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)