1

10

100

1000

FREQUENCY (kHz)

0.1

1

10

100

VCC = 15V

VCC = 10V

VCC = 5V

TA = 25°C

CL = 2200pF

100

1

1k

100

10k

CAPACITIVE LOAD (pF)

0.1

10

1000

f = 500kHz

f = 100kHz

f = 10kHz

TA = 25°C

VCC = 12V

12

LM5111

SNVS300H – JULY 2004 – REVISED SEPTEMBER 2016

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Copyright © 2004–2016, Texas Instruments Incorporated

Typical Application (continued)

9.2.2 Detailed Design Procedure

9.2.2.1 VCC

Although quiescent VCC current is very low, total supply current will be higher, depending on OUTA and OUTB

current and the programmed oscillator frequency. Total VCC current is the sum of quiescent VCC current and the

average OUT current. Knowing the operating frequency and the MOSFET gate charge (Qg), average OUT

current can be calculated using Equation 1.

IOUT = Qg × f

where

•

f is frequency

(1)

For the best high-speed circuit performance, two VCC bypass capacitors are recommended to prevent noise

problems. The use of surface mount components is highly recommended. A 0.1-µF ceramic capacitor should be

located closest to the VDD to ground connection. In addition, a larger capacitor (such as 1 µF and above) with

relatively low ESR should be connected in parallel, to help deliver the high current peaks to the load. The parallel

combination of capacitors should present a low impedance characteristic for the expected current levels in the

driver application.

9.2.3 Application Curves

Figure 13. Supply Current vs Frequency

Figure 14. Supply Current vs Capacitive Load