MIC4827BMM Micrel Inc, MIC4827BMM Datasheet - Page 9

• Manufacturer Part Number: MIC4827BMM
• Description: IC EL DRIVER 180VPP OUT 8-MSOP
• Manufacturer: Micrel Inc
• Type: EL Lamp Driverr

Specifications of MIC4827BMM

• Frequency: 60 ~ 1000 Hz
• Current - Supply: 21µA
• Voltage - Supply: 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Supply Current: 21µA
• Meter Display Type: Electroluminescent Lamp
• Supply Voltage Range: 1.8V To 5.5V
• Driver Case Style: MSOP
• No. Of Pins: 8
• Operating Temperature Range: -40°C To +85°C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Output: -
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant, Contains lead / RoHS non-compliant

Application Information
Inductor
In general, smaller value inductors, which can handle
more current, are more suitable to drive larger size
lamps. As the inductor value decreases, the switching
frequency (controlled by R
avoid saturation or the input voltage should be
increased. Typically, inductor values ranging from 220µH
to 560µH can be used. Murata offers the LQH3C series
up to 560µH and LQH4C series up to 470µH, with low
DC resistance. A 220µH Murata (LQH4C221K04)
inductor is recommended for driving a lamp size of 3
square inches. It has a maximum DC resistance of 4.0Ω
Pre-designed Application Circuit
Micrel, Inc.
July 2009
GRM42-6X5R106K6.3
Li-Ion Battery
3.0V to 4.2V
V
IN
10 F/6.3V
SW
GRM39X7R 224K10
Murata
) should be increased to
C2
0.22 F/10V
3.3V
V
Murata
IN
Figure 5. Typical 100Hz EL Driver for 3in
C1
28mA
3.32M
I
IN
R2
V
332k
180V
R1
A
– V
TIME (2ms/div)
1
2
3
4
PP
VDD
RSW
REL
GND
B
LQH4C221K04
9
MIC4827
Murata
220 H
Diode
The diode must have a high reverse voltage (150V),
since the output voltage at the CS pin can reach up to
110V. A fast switching diode with lower forward voltage
and higher reverse voltage (150V), such as BAV20WS,
can be used to enhance efficiency.
Output Capacitor
Low ESR capacitors should be used at the regulated
boost output (CS pin) of the MIC4827 to minimize the
switching output ripple voltage. Selection of the capacitor
value will depend upon the peak inductor current,
inductor size, and the load. MuRata offers the GRM42-6
series with up to 0.047µF at 100V, with a X7R
temperature coefficient in 1206 surface-mount package.
Typically, values ranging from 0.01µF to 0.1µF at 100V
can be used for the regulated boost output capacitor
L1
106Hz
F
EL
SW
CS
VA
VB
5
6
8
7
3in
BAV20WS
Lamp Size
2
2
D1
LAMP
Lamp
3in
2
C
0.01 F/100V
GRM40X7R103K
OUT
M9999-070709-A
[phone]
MIC4827