MAX8643AETG+ Maxim Integrated Products, MAX8643AETG+ Datasheet - Page 14

• Manufacturer Part Number: MAX8643AETG+
• Description: IC REG STP DWN 3A 24-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX8643AETG+

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.6 ~ 3.2 V
• Current - Output: 3A
• Frequency - Switching: 500kHz ~ 2MHz
• Voltage - Input: 2.35 ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-TQFN Exposed Pad
• Power - Output: 2.22W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3A, 2MHz Step-Down Regulator
with Integrated Switches
where C
age, t
C
(as defined in the Output-Capacitor Selection section).
Depending on the application, one of these parameters
may drive the selection of the others. See the Starting into
Prebias Output waveform in the Typical Operating
Characteristics section for an example selection of the
above parameters. Connecting the PREBIAS pin to GND
disables the prebias soft-start feature and causes the
MAX8643A to discharge any voltage present on the out-
put capacitors and then commence its soft-start.
Careful PCB layout is critical to achieve clean and stable
operation. It is highly recommended to duplicate the
MAX8643 EV kit layout for optimum performance. If devia-
tion is necessary, follow these guidelines for good PCB
layout:
1) Connect input and output capacitors to the power
2) Place capacitors on V
3) Keep the high-current paths as short and wide as
14
SS
ground plane; connect all other capacitors to the sig-
nal ground plane.
possible to the IC and its corresponding pin using
direct traces. Keep power ground plane (connected
to PGND) and signal ground plane (connected to
GND) separate.
possible. Keep the path of switching current short
and minimize the loop area formed by LX, the out-
put capacitors, and the input capacitors.
, and I
______________________________________________________________________________________
SS
O
is the soft-start time set by the soft-start capacitor
P-P
is the output capacitor, V
is the peak-to-peak inductor ripple current
PCB Layout Considerations and
DD
Thermal Performance
, V
IN
, and SS as close as
O
is the output volt-
4) Connect IN, LX, and PGND separately to a large
5) Ensure all feedback connections are short and
6) Route high-speed switching nodes, such as LX,
copper area to help cool the IC to further improve
efficiency and long-term reliability.
direct. Place the feedback resistors and compensa-
tion components as close to the IC as possible.
away from sensitive analog areas (FB, COMP).
TOP VIEW
*EP = EXPOSED PAD.
PGND
PGND
EN
IN
IN
IN
19
20
21
22
23
24
+
18
1
*EP
17
2
THIN QFN
MAX8643A
16
Pin Configuration
3
15
4
14
5
13
6
12
11
10
9
8
7
PWRGD
FREQ
OUT
FB
COMP
GND