MAX1847EEE Maxim Integrated Products, MAX1847EEE Datasheet - Page 17

• Manufacturer Part Number: MAX1847EEE
• Description: Current Mode PWM Controllers
• Manufacturer: Maxim Integrated Products

Specifications of MAX1847EEE

• Case: ssop
• Dc: 05+
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

as the output capacitor (C
the RMS current for the input capacitor is the same as the
output capacitor. The capacitor value and ESR must be
selected to reduce noise to an acceptable value and also
handle the ripple current (I
In addition to C
capacitors are required with the MAX1846/MAX1847.
Bypass REF to GND with a 0.1µF or larger capacitor.
Bypass V
bypass capacitors should be located as close to their
respective pins as possible.
Good PC board layout and routing are required in high-
frequency-switching power supplies to achieve good reg-
ulation, high efficiency, and stability. It is strongly
recommended that the evaluation kit PC board layouts be
followed as closely as possible. Place power components
Figure 2. MAX1846 Main Application Circuit
I
NRMS
L
=
to GND with a 0.47µF or larger capacitor. All
(
I
1 2
−
.
C
IN
COMP2
D
______________________________________________________________________________________
x I
MAX
PC Board Layout Guidelines
and C
O
)
NRMS
x D
NOTE: APPLICATIONS A & B USE POS CAPACITORS. APPLICATIONS C & D USE ALUMINUM ELECTROLYTIC CAPACITORS.
OUT
OUT
C
COMP
). Under ideal conditions,
, other ceramic bypass
) where:
MAX
Bypass Capacitor
R
−
R
0.47µF
COMP
FREQ
APPLICATION B
D
V
IN
MAX
High-Efficiency, Current-Mode,
ONLY
2
3
2
4
REF
COMP
FREQ
0.1µF
VL
1
MAX1846
Inverting PWM Controller
IN
GND
10
PGND
6
EXT
CS
FB
as close together as possible, keeping their traces short,
direct, and wide. Avoid interconnecting the ground pins
of the power components using vias through an internal
ground plane. Instead, keep the power components
close together and route them in a “star” ground configu-
ration using component-side copper, then connect the
star ground to internal ground using multiple vias.
The MAX1846/MAX1847 are extremely versatile devices.
Figure 2 shows a generic schematic of the MAX1846.
Table 1 lists component values for several typical appli-
cations. These component values also apply to the
MAX1847. The first two applications are featured in the
MAX1846/MAX1847 EV kit.
C
IN
9
8
7
5
22k
P
L1
R
CS
C
Main Application Circuits
FB
D1
R1
R2
C
OUT
V
OUT
17