LM4040C datasheet(28/61 Pages) TI2

28 / 61 page

8.2.2.3 Output Capacitor

The LM4040 does not require an output capacitor across cathode and anode for stability. However, if an output

bypass capacitor is desired, the LM4040 is designed to be stable with all capacitive loads.

8.2.2.4 SOT-23 Connections

There is a parasitic Schottky diode connected between pins 2 and 3 of the SOT-23 packaged device. Thus, pin 3

of the SOT-23 package must be left floating or connected to pin 2.

8.2.2.5 Start-Up Characteristics

In any data conversion system, start-up characteristics are important, as to determine when to safely begin

conversion based upon a steady and settled reference value. As shown in Figure 8-4 allow >20µs from supply

start-up to begin conversion.

1 Hz Rate

LM4040

VIN

Figure 8-3. Test Circuit

8.2.3 Application Curve

−1

−10

VZ = 2.5 V

TJ = 25°C

RS = 30 kW

Response Time (ms)

VIN

−2

−4

−6

−8

−10

−12

Figure 8-4. Startup Response

8.3 Power Supply Recommendations

To not exceed the maximum cathode current, be sure that the supply voltage is current limited.

For applications shunting high currents (15mA max), pay attention to the cathode and anode trace lengths,

adjusting the width of the traces to have the proper current density.

8.4 Layout

8.4.1 Layout Guidelines

Figure 8-5 shows an example of a PCB layout of LM4040XXXDBZ. Some key Vref noise considerations are:

• Connect a low ESR, 0.1μF (CL) ceramic bypass capacitor on the cathode pin node.

• Decouple other active devices in the system per the device specifications.

• Using a solid ground plane helps distribute heat and reduces electromagnetic interference (EMI) noise

pickup.

LM4040A, LM4040B, LM4040C, LM4040D

SLOS456P – JANUARY 2005 – REVISED MARCH 2025

www.ti.com

Submit Document Feedback

Product Folder Links: LM4040A LM4040B LM4040C LM4040D

LM4040C Scheda tecnica(PDF) 28 Page - Texas Instruments

LM4040C Scheda tecnica(HTML) 28 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

Scheda tecnica Scarica

Link URL