MAX8576 MAXIM [Maxim Integrated Products], MAX8576 Datasheet - Page 8

• Manufacturer Part Number: MAX8576
• Description: 3V to 28V Input, Low-Cost, Hysteretic Synchronous Step-Down Controllers
• Manufacturer: MAXIM [Maxim Integrated Products]

3V to 28V Input, Low-Cost, Hysteretic
Synchronous Step-Down Controllers
8
MAX8576/
MAX8577
_______________________________________________________________________________________
—
—
10
1
2
3
4
5
6
7
8
9
PIN
MAX8578/
MAX8579
10
—
—
1
3
4
5
6
7
8
9
2
OCSET
NAME
GND
V
BST
DH
DL
EN
FB
S S
VL
LX
IN
CC
Feedback Input. Regulates at V
voltage. See the Setting the Output Voltage section.
S oft- S tar t. U se an exter nal cap aci tor ( C
ap p r oxi m atel y 4m s soft- star t ti m e for a 0.01µF exter nal cap aci tor . An i nter nal 250nA cur r ent si nk i n
hi ccup m od e g i ves ap p r oxi m atel y 10% d uty cycl e d ur i ng faul t cond i ti ons.
Internal 5V Linear-Regulator Output. Bypass with a 4.7µF or larger ceramic capacitor. Must be
connected to IN for operation from a 3.3V to 5.5V input.
Supply Input (3V to 5.5V). Bypass with a 4.7µF or larger ceramic capacitor to GND.
Ground
Low-Side Gate-Drive Output. Drives the synchronous-rectifier MOSFET.
Boost-Capacitor Connection for High-Side Gate-Drive Output. Connect a 0.1µF ceramic
capacitor from BST to LX and a Schottky or switching diode and a 4.7 series resistor from
BST to VL (MAX8576/MAX8577) or V
External Inductor Connection. Connect LX to the junctions of the MOSFETs and inductor.
High-Side Gate-Drive Output. Drives the high-side MOSFET.
Supply Voltage Input of the Internal Linear Regulator (3V to 28V). Connect to VL for operation
from 3V to 5.5V input. Connect a 0.47µF or larger ceramic capacitor from IN to GND.
Enable Input. A logic low on EN shuts down the converter and discharges the soft-start
capacitor. Drive high or connect to V
Overcurrent-Limit Set. Programs the high-side peak current-limit threshold by setting the
maximum-allowed V
to OCSET; an internal 50µA current sink sets the maximum voltage drop relative to V
Setting the Current Limit section.
DS
voltage drop across the high-side MOSFET. Connect a resistor from IN
FB
= 0.59V. Connect FB to a resistor-divider to set the output
SS
CC
CC
) to ad j ust the soft- star t ti m e. An i nter nal 80k r esi stor g i ves
(MAX8578/MAX8579). See Figure 4.
for normal operation.
FUNCTION
Pin Description
IN
. See the