MAX1822ESA+ Maxim Integrated Products, MAX1822ESA+ Datasheet - Page 7

• Manufacturer Part Number: MAX1822ESA+
• Description: IC POWER SUPPLY HI SIDE 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Switched Capacitor (Charge Pump)r

Specifications of MAX1822ESA+

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 14.5 ~ 27.5 V
• Current - Output: 25mA
• Frequency - Switching: 90kHz
• Voltage - Input: 3.5 ~ 16.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Power - Output: 471mW
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Maximum Power Dissipation: 471 mW
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

internal switches during charge-pump cycles. This may
damage the device.
The MAX1822 is not internally short-circuit protected. In
applications where the output is susceptible to short
circuit, external output short-circuit protection must be
provided. Accomplish this by connecting a resistor
between V
less than 25mA. The resistor value is determined by the
following formula:
Multiple subsystems or modules can be turned on and
off using a single MAX1822 and an open-drain hex
buffer such as the 74C906
buffer outputs are pulled through resistors to the
MAX1822’s V
the number of channels being used with the MAX1822
and power-dissipation limitations. The minimum pullup
resistor value is determined by the number of channels
paralleled on each high-side power supply and the
Figure 4. H-Bridge Motor Controller
0.047µF
0.047µF
OUT
C1
C2
+5V
OUT
and the load to limit output current to
. The pullup resistance depends on
_______________________________________________________________________________________
R
1
7
6
2
CL
C1
C1-
C2+
C2-
Typical Applications
≥
Six High-Side Switches
25
MAX1822
V
GND
V
(Figure 3). The drains of all
CC
CC
mA
One MAX1822 Drives
REVERSE
FORWARD
8
4
Output Protection
V
OUT
5
C3
10µF
11
4
6
9
D1
D2
IN1
IN2
GND
H-BRIDGE MOTOR CONTROL
7
DG303
D3
V+
14
3
High-Side Power Supply
high-side output current from the MAX1822 at a given
supply voltage, calculated as follows:
where V
the output current of the MAX1822.
For example, assuming an output current of 1mA and
six channels, as in Figure 3, the minimum pullup resis-
tor value that will not excessively load the MAX1822 is
about 100kΩ, assuming all six channels are pulled low
at the same time. The value of the pullup resistor also
affects the turn-on time of each FET, and hence the
amount of energy dissipated in the FET during turn-on.
The rate of rise of V
stant of the pullup resistor and FET gate capacitance;
waste power will be dissipated in the FET equal to
(I
An H-bridge motor driver is shown in Figure 4. The
motor direction can be controlled by toggling between
IN1 and IN2 of the DG303 analog switch. Each switch
section turns on the appropriate FET pair, which pass-
es current through the motor in the desired direction.
LOAD
D4
12
S2
S4
S3
S1
10
13
5
)
2
R
OUT
x r
MIN
DS
is the high-side output voltage and I
=
during the RC time period.
V
OUT
GS
x number of channels
IRF541
IRF541
+
is limited by the RC time con-
(
H-Bridge Motor Driver
DC MOTOR
I
OUT
+5V
–
IRF541
IRF541
)
OUT
is
7