Datasheet
MAX8566
High-Efficiency, 10A, PWM
Internal-Switch Step-Down Regulator
14 ______________________________________________________________________________________
Undervoltage Lockout (UVLO)
The UVLO circuitry inhibits switching when V
DD
is
below 2V. Once V
DD
rises above 2V, UVLO clears and
the soft-start function activates. A 100mV hysteresis is
built in for glitch immunity.
Monotonic Startup Modes (MODE)
When starting up into a precharged output, the MAX8566
does not discharge the output prior to entering soft-start
(known as monotonic startup). Drive MODE to 1/3 of V
DD
to enable monotonic startup mode. Connect MODE to
GND to disable monotonic startup mode.
High-Side MOSFET Driver Supply (BST)
The gate-drive voltage for the high-side, n-channel
switch is generated by a flying-capacitor boost circuit.
The capacitor between BST and LX is charged from the
V
LSS
supply while the low-side MOSFET is on. When
the low-side MOSFET is switched off, the stored voltage
of the capacitor is stacked above LX to provide the
necessary turn-on voltage for the high-side internal
MOSFET.
Frequency Select (FREQ)
The switching frequency is resistor programmable from
250kHz to 2.4MHz. Set the switching frequency of the
IC with a resistor from FREQ to GND (R
FREQ
). R
FREQ
is
calculated as:
where f
S
is the desired switching frequency in Hz.
SYNC Function (SYNC, SYNCOUT)
The MAX8566 features a SYNC function that allows the
switching frequency to be synchronized to any frequen-
cy between 250kHz to 2.4MHz. Drive SYNC with a
R
k
sf
s
FREQ
s
=×
⎛
⎝
⎜
⎞
⎠
⎟
−
50
095
1
005
Ω
.
.
µ
µ
IN
LSS
IN
IN
IN
IN
LX
BST
LX
LX
LX
LX
23
18
19
20
21
28
22
5
4
6
7
8
LX
10
SYNCOUT
30
26
LX
11
LX
12
PGND
17
PGND
16
PGND
15
PGND
14
PGND
13
32
2
9
24
3
V
DD
PWRGD
27
1
25
29
31
EN
MODE
REFIN
SYNC
FREQ
GND
FB
COMP
SS
MAX8566
V
IN
2.3V TO 3.6V
V
OUT
1.8V AT 10A
POWER-GOOD
OUTPUT
C3
0.22µF
R7
16.9kΩ
C9
330pF
C10
22pF
C8
120pF
3300pF
C5
0.047µF
L1
0.47µH
C4
1µF
R2
20kΩ
R17
20kΩ
R18
10kΩ
R5
24.9kΩ
R4
100Ω
R6
12.4kΩ
2kΩ
R3
50kΩ
R1
10Ω
C2
10µF
C6
22µF
C7
22µF
C11
0.022µF
C1
10µF
C24
OPEN
Figure 3. Typical Application Circuit
Figure 2. Soft-Start Implementation with External Reference
MAX8566
REFIN
C
R2
R1