Datasheet

MAX5066
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
14 ______________________________________________________________________________________
MOSFET Gate Drivers (DH_, DL_)
The high-side drivers (DH1 and DH2) and low-side dri-
vers (DL1 and DL2) drive the gates of external n-channel
MOSFETs. The high-peak sink and source current capa-
bility of these drivers provides ample drive for the fast
rise and fall times of the switching MOSFETs. Faster rise
and fall times result in reduced switching losses. For low-
output, voltage-regulating applications where the duty
cycle is less than 50%, choose high-side MOSFETs (Q2
and Q4, Figure 6) with a moderate R
DS(ON)
and a very
low gate charge. Choose low-side MOSFETs (Q1 and
Q3, Figure 6) with very low R
DS(ON)
and moderate gate
charge. The driver block also includes a logic circuit that
provides an adaptive nonoverlap time (30ns typical) to
2 x f
SW
(V/S)
RAMP
CLK
CSP_
CSN_
GM
IN
EN_
1.225V
CLP_
V
DD
BST_
DH_
LX_
DL_
PGND
A
V
= 36
PWM
COMPARATOR
PEAK-CURRENT
COMPARATOR
52.5mV
S
R
Q
Q
g
M
= 500µS
Figure 3. Current Comparator and MOSFET Driver Logic
LOAD
C
OUT
V
OUT
V
REF
= 0.61V
R
F
R
1
R
2
EAN_
EAOUT_
Figure 4. Voltage Error Amplifier
LOAD (A)
V
CNTR
NO LOAD
1/2 LOAD
FULL LOAD
VOLTAGE-POSITIONING WINDOW
V
CNTR
+ ∆V
OUT
/2
V
CNTR
- ∆V
OUT
/2
Figure 5. Defining the Voltage-Positioning Window