Datasheet

The internal V
L
linear regulator can source over 50mA to
supply the IC, power the low-side gate driver, charge the
external boost capacitor, and supply small external
loads. When driving large FETs, little or no regulator cur-
rent may be available for external loads.
For example, when switched at 600kHz, a single large
FET with 18nC total gate charge requires 18nC
✕
600kHz
= 11mA. To drive larger MOSFETs, or deliver larger
loads, connect V
L
to an external power supply from
4.75V to 5.5V.
MAX1875/MAX1876
Dual 180° Out-of-Phase PWM Step-
Down Controllers with POR
_______________________________________________________________________________________ 9
CONVERTER #1
R
S
Q
ILIM1
DL1
PGND
LX1
DH1
BST1
V
L
- 0.5V
FB1
COMP1
SOFT-START
DAC
OSCILLATOR
OSC
SYNC
CK0
V+
5V LINEAR
REGULATOR
V
L
GND
REF
DL2
LX2
DH2
BST2
ILIM2FB2
COMP2
CONVERTER 2
RESET
EN
UVLO
AND
SHUTDOWN
V
REF
2.0V
MAX1875
MAX1876
RST
(MAX1876 ONLY)
V
REF
V
L
Q
5µA
Figure 2. Functional Diagram