Datasheet

2
TOT DS(ON) OUT(RMS)
P R (I )= ´
VM
OUT1
OUT2
GND
VCC
nSLEEP
IN1/PH
IN2/EN
8
7
6
5
1
2
3
4
DRV8837 and
DRV8838
PAD
M
VCC
0.1 µF
VM
0.1 µF
DRV8837, DRV8838
www.ti.com SLVSBA4C –JUNE 2012–REVISED FEBRUARY 2014
8 Applications and Implementation
8.1 Application Information
The DRV883x is device is used to drive one DC motor or other devices like solenoids. The following design
procedure can be used to configure the DRV883x.
8.2 Typical Applications
Figure 6. Schematic of DRV883x Application
8.2.1 Design Requirements
Table 5 shows required parameters for a typical usage case.
Table 5. System Design Requirements
Design Parameter Reference Example Value
Motor supply voltage VM 9 V
Logic supply voltage VCC 3.3 V
Target RMS current I
OUT
0.8 A
8.2.2 Detailed Design Procedure
8.2.2.1 Power Dissipation
Power dissipation in the DRV883x is dominated by the power dissipated in the output FET resistance, or R
DS(ON)
.
Average power dissipation when running a stepper motor can be roughly estimated by:
where
• P
TOT
is the total power dissipation
• R
DS(ON)
is the resistance of the HS plus LS FETs
• I
OUT(RMS)
is the RMS or DC output current being supplied to the load (1)
The maximum amount of power that can be dissipated in the device is dependent on ambient temperature and
heatsinking.
Note that R
DS(ON)
increases with temperature, so as the device heats, the power dissipation increases.
The DRV883x has thermal shutdown protection. If the die temperature exceeds approximately 150°C, the device
will be disabled until the temperature drops to a safe level.
Any tendency of the device to enter thermal shutdown is an indication of either excessive power dissipation,
insufficient heatsinking, or too high an ambient temperature.
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