MAS6240 Datasheet, PDF (1/10 Pages) Micro Analog systems – Piezo Driver with Multi-Mode Charge Pump

DA6240.001
20 November 2006
MAS6240
Piezo Driver with Multi-Mode Charge Pump
This is preliminary information on a new
product under development. Micro Analog
Systems Oy reserves the right to make any
changes without notice.
• Both Single Ended and
Differential Output
• Three-Step Volume Adjusting
• Up to 18Vpp Output from 3V
Supply
• One Wire Audio & Shutdown
Control
• High Efficiency
• Solution without Inductors
• Low External Part Count
DESCRIPTION
MAS6240 is a piezo driver device that can drive
outputs up to 18Vpp from 3V supply. An internal
three-mode charge pump generates boosted supply
voltage for piezo driver. For adjusting the piezo
element sound volume, the charge pump can
operate in either of a 1x, 2x or 3x mode. In 1x mode
the input voltage is bypassed to the output, in 2x or
3x mode the input voltage is boosted up accordingly
2 or 3 times. Charge pump mode is selected by
control pins EN1 and EN2 (see Table1 at page 2).
MAS6240 is an easy and low-cost solution for piezo
driver, since only 4 small value capacitors are
needed in addition to sound element - the use of
inductors can be avoided. The inductorless design
also causes significantly less disturbance to the
surrounding circuits making it an ideal choice for
sensitive designs. Its charge pump switches at
1MHz, allowing to use as small as 100nF external
capacitors.
Control logic is switching the charge pump on at
first rising signal of digital input (DIN) pin. The
switch-off signal will be generated while the signal at
DIN has been low at least for 10ms. The piezo
driver is enabled at a second rising edge of a pulse
at DIN and the signal is transferred to piezo output
VO1. The same signal is inverted into output VO2
for using differential output.
Continuous logic high level at DIN input causes the
charge pump to be turned ON but leaves the audio
amplifier disabled. In that state the charge pump
output can be used to power the external LEDs or
any other external circuit. The output voltage is still
selectable at three steps.
In "disabled" mode (DIN has been low for 10ms) all
functional blocks are switched off to achieve the
quiescent current less than 1µA.
See more information in the chapter Detailed
Description.
FEATURES
Thin 0.75 mm QFN 12 package
Piezo Driver
• Three-Step Volume Adjusting
• Both Single Ended and Differential Output
• Up to 18Vpp Output from 3V Supply
• One Wire Audio & Shutdown Control
Charge Pump
• Low External Part Count
• Solution without Inductors
• 1 MHz Switching Frequency
• Multi-Mode Charge Pump (1x/2x/3x)
APPLICATIONS
•Wrist Watches
•Alarm Clocks
•Handheld GPS devices
•PDAs
•Portable Device with Sound Feature
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