33984 Datasheet, PDF (29/38 Pages) Freescale Semiconductor, Inc – Dual Intelligent High-current Self-protected Silicon High Side Switch (4.0 mOhm)

TYPICAL APPLICATIONS
TYPICAL APPLICATIONS
V_PWR
V_DD
Voltage
Regulator
V_DD
V_DD NC V_PWR
V_DD
V_PWR
MCU
2.2k 10k
100 nF
I/O
I/O
SCLK
CS
I/O
SI
SO
I/O
A/D
10 k
10 k
10 k
10 k
10 k
10 k
1k
10 _VDD
10 µF
VPWR ¹⁴
2.5 µF
10 nF
2
4
12
8
7
3
11
9
5
1
6
RFSI
WAKE
IN0
IN1
SCLK
CS
RST
SO
SI
FS
CSNS
FSI
33984
HS1 ¹⁵
HS0 ¹⁶
GND ¹³
LOAD
LOAD
Figure 11. Typical Applications
The loads must be chosen in order to guarantee the device
normal operating conditions for junction temperatures from -
40 to 150°C. In case of permanent short-circuit conditions,
the duration and number of activation cycles must be limited
with a dedicated MCU fault management, using the fault
reporting through the SPI. When driving DC motor or
Solenoid loads demanding multiple switching, an external
recirculation device must be used to maintain the device in its
Safe Operating Area.
Two application notes are available:
• AN3274, which proposes safe configurations of the
eXtreme Switch devices in case of application faults, and
to protect all circuitry with minimum external components.
• AN2469, which provides guidelines for Printed Circuit
Board (PCB) design and assembly.
Development effort will be required by the end users to
optimize the board design and PCB layout, in order to reach
electromagnetic compatibility standards (emission and
immunity).
OUTPUT CURRENT MONITORING
This section relates to the output current monitoring for
33984, Dual 4.0 mΩ High Side Switch. This device is a self-
protected silicon switch used to replace electromechanical
relays, fuses, and discrete circuits in power management
applications. The MC33984 features a current recopy which
is proportional to the load current. It can be configured
between 2 ratios via SPI (CSR0 and CSR1).
This section presents the current recopy tolerance of the
device and the improvement of this feature with the
calibration practice.
CURRENT RECOPY TOLERANCE
The Current Sense Ratio Accuracies described page 9
and 10 (CSR0_ACC and CSR1_ACC) take into account:
• part to part deviation due to manufacturing,
• ambient temperature derating (from -40 to 125°C),
• battery voltage range (from 9 to 16 V).
Thanks to statistical data analysis performed on 3
production lots (initial testing only), the effect of each
contributor has been demonstrated.
Analog Integrated Circuit Device Data
Freescale Semiconductor
33984
29