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
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.
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.
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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DA6240.001
20 November 2006
PIN DESCRIPTION
Pin Description
Control signal input for setting charge pump mode
Control signal input for setting charge pump mode
Enable signal + Digital signal input
Flying capacitor negative terminal
Supply ground
Digital audio signal output
Digital audio signal output
Flying capacitor negative terminal
Flying capacitor positive terminal
Charge pump output
Flying capacitor positive terminal
Power supply
Symbol
EN1
EN2
DIN
CN1
GND
VO2
VO1
CN2
CP1
VOUT
CP2
VIN
Type
DI
DI
DI
I/O
G
DO
DO
I/O
I/O
AO
I/O
P
X-coordinate
152
µm
152
µm
152
µm
672
µm
808
µm
980
µm
980
µm
980
µm
980
µm
765
µm
612
µm
447
µm
Y-coordinate
989
µm
804
µm
588
µm
200
µm
202
µm
225
µm
378
µm
558
µm
711
µm
1000
µm
1000
µm
999
µm
G = Ground, P = Power, D = Digital, A = Analog, I = Input, O = Output.
Note:
Because the substrate of the die is internally connected to GND, the die has to be connected to GND or
left floating. Please make sure that GND is the first pad to be bonded. Pick-and-place and all component
assembly are recommended to be performed in ESD protected area.
Note:
Pad coordinates are measured from the left bottom corner of the chip to the center of the pads. The
coordinates may vary depending on sawing width and location, however, distances between pads are accurate.
Note:
See IC outlines on a page 6 for IC layout.
ABSOLUTE MAXIMUM RATINGS
Parameter
Supply Voltage
Outputs and Flying
Capacitors Pins Voltages
Symbol
VIN
VOUT,
CP1, CP2,
CN1, CN2,
VO1, VO2
DIN,
EN1, EN2
t
SC
Conditions
Min
-0.3
-0.3
Max
5.5
10
Unit
V
V
Voltage Range for Input
Pins
VOUT Short-Circuit
Duration
Storage Temperature
ESD Rating
-0.3
Note 1
VIN + 0.3
Indefinite
V
-55
Human Body Model (HBM)
+150
1
C
kV
o
NOTE 1.
SHORT CIRCUIT CURRENT INTERNALLY LIMITED.
RECOMMENDED OPERATING CONDITIONS
All voltages with respect to ground.
Parameter
Operating Junction
Temperature
Operating Ambient
Temperature
Operating Supply Voltage
Symbol
T
J
T
A
V
IN
Conditions
Min
-40
-40
2.5
Typ
Max
+125
Unit
°
C
°
C
V
+27
3.0
+85
3.3
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DA6240.001
20 November 2006
DETAILED DESCRIPTION
MAS6240 first pulse skipping
10
9
8
7
6
voltage [V]
5
4
3
2
1
0
-1
-20
-10
0
10
20
30
40
50
60
70
VO1
DIN
time [ms]
Figure 3: Enabling output VO1
The piezo driver is enabled at the second rising edge of the pulse at DIN, thus the signal is transferred to the
piezo output VO1. An output VO2 is enabled at the same time, but it is optional to take it in use. Control logic is
switching the charge pump on at first rising signal of digital input DIN pin. If only one continous pulse is fed to the
input DIN, the output VO1 is not enabled. This make it possible to control e.g. a white LED or other device
through pin VOUT while charge pump is enabled, without enabling the piezo output VO1.
MAS6240 first pulse skipping & power down delay
10
8
6
voltage [V]
DIN
VO2
4
2
0
-20
-2
time [sec]
-10
0
10
20
30
40
50
60
70
Figure 4: Disabling VO2
Figure 4 is drawn in the case of VO2. The switch-off signal will be generated after the signal at DIN has been low
at least for 10 ms. In the figure 4 the switch-off delay is about 25 ms. Again when new pulses are fed into DIN,
the charge pump and piezo driver will be enabled.
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