MAX1674-MAX1676 Maxim, MAX1674-MAX1676 Datasheet - Page 12

• Manufacturer Part Number: MAX1674-MAX1676
• Description: High-Efficiency / Low-Supply-Current / Compact / Step-Up DC-DC Converters
• Manufacturer: Maxim

12
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
Although not required, a Schottky diode (such as the
MBR0520) connected between LX and OUT allows
lower start-up voltages (Figure 10) and is recommend-
ed for single-cell operation. Note that adding this diode
provides no significant efficiency improvement.
Careful printed circuit layout is important for minimizing
ground bounce and noise. Keep the IC’s GND pin and
the ground leads of the input and output filter capaci-
tors less than 0.2in (5mm) apart. In addition, keep all
connections to the FB and LX pins as short as possi-
ble. In particular, when using external feedback resis-
tors, locate them as close to the FB as possible. To
maximize output power and efficiency and minimize
output ripple voltage, use a ground plane and solder
the IC’s GND directly to the ground plane.
______________________________________________________________________________________
PC Board Layout and Grounding
Optional External Rectifier
Figure 10. Adding a Schottky Diode for Single-Cell Operation
TRANSISTOR COUNT: 751
R3
R4
0.1 F
200
R1
BATT
(MAX1676)
LBI
REF
CLSEL
(MAX1676)
MAX1674
MAX1675
MAX1676
GND
Package Information
SHDN
OUT
LBO
LX
FB
Chip Information
47 F
R2
100k
0.1 F
V
IN
LOW-BATTERY
OUTPUT
22 H
SINGLE CELL
MBR0520
47 F