LM5085SDE/NOPB National Semiconductor, LM5085SDE/NOPB Datasheet - Page 16
![IC BUCK ADJ 8LLP](/photos/6/51/65153/pkg_sda08a_sml.jpg)
LM5085SDE/NOPB
Manufacturer Part Number
LM5085SDE/NOPB
Description
IC BUCK ADJ 8LLP
Manufacturer
National Semiconductor
Series
PowerWise®r
Type
Step-Down (Buck)r
Datasheet
1.LM5085MYENOPB.pdf
(22 pages)
Specifications of LM5085SDE/NOPB
Design Resources
LM(2)5085 Quick Start Calculator
Internal Switch(s)
No
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
1.25 ~ 75 V
Frequency - Switching
Up to 1MHz
Voltage - Input
4.5 ~ 75 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
8-LLP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Output
-
Power - Output
-
Other names
LM5085SDETR
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LM5085SDE/NOPB
Manufacturer:
NS
Quantity:
70
Part Number:
LM5085SDE/NOPB
Manufacturer:
TI/德州仪器
Quantity:
20 000
www.national.com
C
vides not only noise filtering and stability for the VCC regula-
tor, but also provides the surge current for the PFET gate
drive. The typical recommended value for C
good quality, low ESR, ceramic capacitor is recommended.
C
VCC pins. If the selected PFET has a Total Gate Charge
specification of 100 nC or larger, or if the circuit is required to
operate at input voltages below 7 volts, a larger capacitor may
be required. The maximum recommended value for C
1 µF.
IC Power Dissipation: The maximum power dissipated in the
LM5085 package is calculated using Equation 12 at the max-
VCC
VCC
: The capacitor at the VCC pin (from VIN to VCC) pro-
must be located as close as possible to the VIN and
VCC
is 0.47 µF. A
FIGURE 4. Example Circuit
VCC
is
16
imum input voltage. The Total Gate Charge for the Si7465
PFET is specified to be 40 nC (max) in its data sheet. There-
fore the total power dissipation within the LM5085 is calcu-
lated to be:
Using an MSOP-8EP package with a θ
a temperature rise of 34°C from junction to ambient.
Final Design Example Circuit
The final circuit is shown in Figure 4, and its performance is
presented in Figure 5 through Figure 8.
P
DISS
= 55V x ((40 nC x 300 kHz) + 1.4 mA) = 737 mW
JA
of 46°C/W produces
30057742