mc ) 0.072F

where R

mum input voltage, g

tance found in the Electrical Characteristics table, and R

D-

SON

is the value chosen from the graph "R

the Typical Performance Characteristics section.

LAYOUT CONSIDERATIONS

The LM2716 uses two separate ground connections, PGND

for the drivers and boost NMOS power device and AGND for

the sensitive analog control circuitry. The AGND and PGND

pins should be tied directly together at the package. The

feedback and compensation networks should be connected

directly to a dedicated analog ground plane and this ground

plane must connect to the AGND pin. If no analog ground

plane is available then the ground connections of the feed-

back and compensation networks must tie directly to the

AGND pin. Connecting these networks to the PGND can

inject noise into the system and effect performance.

The input bypass capacitor C

be placed close to the IC. This will reduce copper trace

resistance which effects input voltage ripple of the IC. For

additional input voltage filtering, a 100nF bypass capacitor

can be placed in parallel with C

shunt any high frequency noise to ground. The output ca-

pacitors, C

the IC. Any copper trace connections for the C

tors can increase the series resistance, which directly effects

output voltage ripple. The feedback network, resistors R

FB1

and R

the inductor, to minimize copper trace connections that can

inject noise into the system. Trace connections made to the

inductors and schottky diodes should be minimized to re-

duce power dissipation and increase overall efficiency. See

Figure 3, Figure 4, and Figure 5 for a good example of

proper layout. For more detail on switching power supply

layout considerations see Application Note AN-1149: Layout

Guidelines for Switching Power Supplies.

Application Information

Some recommended Inductors (others may be used)

Manufacturer

Inductor

Contact Information

Coilcraft

DO3316 and DO5022 series

www.coilcraft.com

Coiltronics

DRQ73 and CD1 series

www.cooperet.com

Pulse

P0751 and P0762 series

www.pulseeng.com

Sumida

CDRH8D28 and CDRH8D43 series

www.sumida.com

Some recommended Input and Output Capacitors (others may be used)

Manufacturer

Capacitor

Contact Information

Vishay Sprague

293D, 592D, and 595D series tantalum

www.vishay.com

Taiyo Yuden

High capacitance MLCC ceramic

www.t-yuden.com

Cornell Dubilier

ESRD seriec Polymer Aluminum Electrolytic

SPV and AFK series V-chip series

www.cde.com

Panasonic

High capacitance MLCC ceramic

EEJ-L series tantalum

www.panasonic.com

www.national.com

14