LM3676SD-ADJ/NOPB National Semiconductor, LM3676SD-ADJ/NOPB Datasheet - Page 15

• Manufacturer Part Number: LM3676SD-ADJ/NOPB
• Description: IC CONV DC-DC 600MA ADJ 8-LLP
• Manufacturer: National Semiconductor
• Type: Step-Down (Buck)r

Specifications of LM3676SD-ADJ/NOPB

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.1 ~ 3.3 V
• Current - Output: 600mA
• Frequency - Switching: 2MHz
• Voltage - Input: 2.9 ~ 5.5 V
• Operating Temperature: -30°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-LLP
• Power - Output: 1.78W
• For Use With: LM3676SD-ADJEV - BOARD EVALUATION LM3676SD-ADJ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM3676SD-ADJTR

4.7 µF for C
10 µF for C
OUTPUT CAPACITOR SELECTION
A ceramic output capacitor of 10 µF, 6.3V is sufficient for most
applications. Use X7R or X5R types; do not use Y5V. DC bias
characteristics of ceramic capacitors must be considered
when selecting case sizes like 0805 and 0603. DC bias char-
acteristics vary from manufacturer to manufacturer and dc
bias curves should be requested from them as part of the ca-
pacitor selection process.
The minimum output capacitance to guarantee good per-
formance is 5.75µF at 1.8V dc bias including tolerances
and over ambient temperature range. The output filter ca-
pacitor smoothes out current flow from the inductor to the
load, helps maintain a steady output voltage during transient
load changes and reduces output voltage ripple. These ca-
pacitors must be selected with sufficient capacitance and
sufficiently low ESR to perform these functions.
The output voltage ripple is caused by the charging and dis-
charging of the output capacitor and by the R
calculated as:
Voltage peak-to-peak ripple due to capacitance can be ex-
pressed as follow:
GRM21BR60J475K
GRM21BR60J106K
C2012X5R0J475K
C1608X5R0J475K
C2012X5R0J106K
C1608X5R0J106K
JMK212BJ475K
JMK212BJ106K
LPO3310-222MX
CDRH2D14-2R2
DO3314-222MX
ELL5GM2R2N
Model
OUT
IN
Model
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
TABLE 2. Suggested Capacitors and Their Suppliers
Type
TABLE 1. Suggested Inductors and Their Suppliers
Panasonic
Coilcraft
Coilcraft
Vendor
Sumida
ESR
and can be
Taiyo-Yuden
Taiyo-Yuden
Vendor
Murata
Murata
TDK
TDK
TDK
TDK
15
Dimensions LxWxH(mm)
Voltage peak-to-peak ripple due to ESR can be expressed as
follow:
V
Because these two components are out of phase the rms (root
mean squared) value can be used to get an approximate val-
ue of peak-to-peak ripple.
The peak-to-peak ripple voltage, rms value can be expressed
as follow:
Note that the output voltage ripple is dependent on the induc-
tor current ripple and the equivalent series resistance of the
output capacitor (R
The R
dependent); make sure the value used for calculations is at
the switching frequency of the part.
PP-ESR
3.2 x 3.2 x 1.55
3.3 x 3.3 x 1.4
3.3 x 3.3 x 1.0
5.2 x 5.2 x 1.5
ESR
= (2 * I
is frequency dependent (as well as temperature
Voltage Rating
RIPPLE
ESR
6.3V
6.3V
6.3V
6.3V
6.3V
6.3V
6.3V
6.3V
) * R
).
ESR
0805 (2012)
0805 (2012)
0805 (2012)
0603 (1608)
0805 (2012)
0805 (2012)
0805 (2012)
0603 (1608)
D.C.R (max)
Inch (mm)
Case Size
200 mΩ
150 mΩ
53 mΩ
94 mΩ
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