LM3668_08 Datasheet, PDF (3/18 Pages) National Semiconductor (TI) – 1A, High Efficiency Dual Mode Single Inductor Buck-Boost DC/DC Converter

Connection Diagrams and Package Mark Information
Top View
20191402
Bottom View
20191403
Pin Descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
DAP
Pin Name
VOUT
SW2
PGND
SW1
PV_IN
EN
VDD
NC*
SGND
MODE/SYNC
VSEL
FB
DAP
Description
Connect to output capacitor.
Switching Node connection to the internal PFET switch (P2) and NFET synchronous rectifier (N2).
Power Ground.
Switching Node connection to the internal PFET switch (P1) and NFET synchronous rectifier (N1).
Supply to the power switch, connect to the input capacitor.
Enable Input. Set this digital input high for normal operation. For shutdown, set low.
Signal Supply input. If board layout is not optimum an optional 1µF ceramic capacitor is suggested
as close to this pin as possible.
No connect. Connect this pin to GND on PCB layout.
Analog and Control Ground.
Mode = LOW, Automatic Mode. Mode= HI, Forced PWM Mode SYNC = external clock
synchronization from 1.6MHz to 2.7MHz (When SYNC function is used, device is forced in PWM
mode).
Voltage selection pin; ( ie: 2.8V/3.3V option) Logic input low = 2.8V and logic high = 3.3V to set output
Voltage.
Feedback Analog Input. Connect to the output at the output filter.
Die Attach Pad, connect the DAP to SGND on PCB layout to enhance thermal performance. It should
not be used as a primary ground connection.
Ordering Information
Order Number
LM3668SD - 3.3¹
LM3668SDX - 3.3¹
LM3668SD-3034²
LM3668SDX-3034²
LM3668SD - 4550
LM3668SDX - 4550
Package
LLP-12
LLP-12
LLP-12
NSC Package
Marking
S016B
S018B
S019B
Supplied As
1000 units, Tape and Reel
4500 units, Tape and Reel
1000 units, Tape and Reel
4500 units, Tape and Reel
1000 units, Tape and Reel
4500 units, Tape and Reel
Note 1: LM3668SD/X-3.3V will soon be replaced by new option LM3668SD/X-2833.
Note 2: As an example, if V_OUT option is 3.0V/3.4V, when V_SEL = Low, set V_OUT to 3V; when V_SEL = high, set V_OUT = 3.4V.
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