Rp _ MAX Rp _ MIN

Rp

Rp _ MIN (1 Y) Rp _ MAX Y

u

u





u

0

10

20

30

40

50

60

0

1

2

3

4

5

6

7

8

Distance (mm)

C003

LDC1051

www.ti.com

SNOSCY0 – MARCH 2014

Feature Description (continued)

Figure 10. Transfer Characteristics Of LDC1051 With Rp_MIN= 1.347 k

Ω And Rp_MAX= 38.785 kΩ

The resonance impedance can be calculated from the digital output code as follows:

Where:

•

Y=Proximity Data/2

7

•

Rp_MAX and Rp_MIN are the maximum and minimum Rp values selected in the respective registers

•

Proximity data is the LDC output, register address 0x22.

(2)

Example: If Proximity data (address 0x22) is 50, Rp_MIN is 2.394 k

Ω, and Rp_MAX is 38.785 kΩ, the

resonance impedance is given by:

Rp=(38785*2394)/(2394×(1-0.3906) + 38785×0.3906) =(92851290)/(15149.421 + 1458.9036)

Rp = 5.59 k

Ω

7.4 Device Functional Modes

7.4.1 Power Modes

The LDC1051 has two power modes:

•

Active Mode : In this mode the Proximity data conversion is enabled.

•

Stand-by Mode: This is the default mode on device power-up. In this mode conversion is disabled.

7.4.2 INTB terminal Modes

The INTB terminal is a configurable output terminal which can be used to drive an interrupt on an MCU. The

LDC1051 provides three different modes on INTB terminal:

1. Comparator Mode

2. Wake-Up Mode

3. DRDY Mode

LDC1051 has built-in High and Low trigger threshold registers which can be used as a comparator with

programmable hysteresis or in a special mode which can be used to wake-up an MCU. These modes are

explained in detail below.

Copyright © 2014, Texas Instruments Incorporated

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