EM6420

Copyright

© 2008, EM Microelectronic-Marin SA

Subject to change without notice

Rev. B, 10/08

Phone: +41.32.755-5111, Fax: +41.32.755-5403

www.emmicroelectronic.com

info@emmicroelectronic.com

Ultra Low Power Capacitive Touch Sensor Interface IC

Description

The EM6420 is an ultra low power Touch Sensor Interface IC

able to scan sequentially up to 16 capacitive sensors. No

software development is required. The device parameters

(number of used sensors, sensors scan frequency, sensors

sensitivity level, IRQ condition) are configurable either from a

host microcontroller through a communication port or through

configuration inputs.

Recognised touch inputs will be signaled with an active edge

at the IRQ pad and data are ready to be read through the

communicaion port by the host MCU. Conditions for the IRQ

to get active are configurable : at the end of every scan, at

the end of a scan if at least one sensor is active or at the end

of a scan if the sensors state has changed.

The EM6420 can also detect the most active sensor in

applications where sensors are tightly spaced. It compares

relative levels among sensors and selects the sensor with the

largest signal strength.

To increase the number of sensors >16, use several EM6420

in parallel.

Depending on the selected supply voltage range, 3 or 4

decoupling capacitors are required for the entire functionality

of the EM6420 from -40 to + 85°C.

Features

Up to 16 analogue sensor inputs

User selectable communication interfaces : 4-wire SPI,

I

User-selectable active edge IRQ output signal

Active high enable input

No software development and tuning required

Development tools and documentations available

Complete solution/module available: IC + sensors

design on any subtract

Electrical Characteristics

Supply voltage

1.2 V to 2.0 V

or

2.2 V to 3.6 V

Power consumption active

8.5 µA @ 3.0 V

Power consumption standby

5.5 µA @ 3.0 V

Power consumption sleep

0.6 µA @ 3.0 V

Nominal sensor capacitance

3 to 31 pF

Sensors scan frequency

1 Hz to 128 Hz *

* frequency depending on number of sensors

COM clock frequency

up to 400 kHz

Availability

Naked die

SMT package MLF40

Design Considerations

The EM6420 is well suited for battery and mains powered

applications where the following features are important :

Tamper proof applications

Nice and clean designs

Touch function to avoid buttons and keys

Slider functions

Hygienic issues, cleaning aspects

Waterproof designs

Applications

Mobile phones, cordless phones

PDA, keyboards

White & brown goods

Toys

Lighting - Sliders for dimming