MAX8655ETN+ Maxim Integrated Products, MAX8655ETN+ Datasheet - Page 14

• Manufacturer Part Number: MAX8655ETN+
• Description: IC STEP-DN REG 25A 56-TQFN-EP
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX8655ETN+

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 0.7 ~ 5.5 V
• Current - Output: 25A
• Frequency - Switching: 200kHz ~ 1MHz
• Voltage - Input: 4.5 ~ 25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 56-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Highly Integrated, 25A, Wide-Input,
Internal MOSFET, Step-Down Regulator
To set the output voltage for the MAX8655, connect FB
to the center of an external resistor-divider from the out-
put to GND (R3 and R5 of Figure 5). Select R5 between
5kΩ and 24kΩ, and then calculate R3 with the following
equation:
where V
placed as close as possible to the IC.
Figure 4. Single-Phase, 350kHz Switching, 6V to 20V Input, and 3.3V/20A Output
14
FSYNC INPUT
SYNC OUTPUT
FOR INTERNAL
OSCILLATOR
OPERATION ONLY
INPUT 6V TO 20V
POWER-OK OUTPUT
______________________________________________________________________________________
FB
CERAMIC
5 x 10μF
C1–C5
= 0.7V or V
76.8kΩ
VL
0.22μF
R8
C15
R
D1
100kΩ
3
R13
=
AVL
Setting the Output Voltage
AVL
R
5
×
REFIN
13kΩ
R14
⎛
⎜
⎝
POK
FSYNC
MODE
SYNCO
BST
GND
N.C.
LXB
PVIN
PVIN
PVIN
PVIN
PVIN
PVIN
10kΩ
Design Procedure
V
R12
V
OUT
FB
. R3 and R5 should be
−
1
R11
140kΩ
⎞
⎟
⎠
0.022μF
AVL
C13
R7
243kΩ
C12
560pF
MAX8655
R5
3.09kΩ
R6
3.09kΩ
11.5kΩ
R3
Figure 5. Setting the Output Voltage with a Resistor Voltage-
Divider
R9
71.5kΩ
11.5kΩ
R4
100pF
C10
3.57kΩ
MAX8655
R2
C8
0.22μF
VLGND
PGND
GND
GND
AVL
EN
VL
LX
LX
LX
LX
LX
LX
IN
LX
FB
C14
1μF
C18
2.2μF
C16
0.22μF
PVIN
R1
1.74kΩ
1.6mΩ
1μH
L1
0.22μF
C9
15μΩ ESR
3 x 220μF
C6–C19
R3
R5
ENABLE
OUTPUT 3.3V
INPUT
UP TO 20A
OFF
ON