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A PRIMER ON ESSENTIALS OF OUTPUT VOLTAGE LIMITATIONS

Typically, overcoming the foremost roadblocks to successfully and reliably applying power and "smart-power" ICs involves an understanding of two critical specifications.

Application Note 29501.1A
APPLICATIONS INFORMATION
A PRIMER ON ESSENTIALS OF OUTPUT VOLTAGE LIMITATIONS
Typically, overcoming the foremost roadblocks to successfully and reliably applying power and "smart-power" ICs involves an understanding of two critical specifications.
COLLECTOR CURRENT
V CE(sus)
OFF "CUSP" ON TIME
V CE(sat)
COLLECTOR VOLTAGE
(BR)CBO
Dwg. GP-047
Figure 1 - Load Line with Resistive Load
INDUCTIVE LOAD LINE
COLLECTOR CURRENT
V CE(sus)
POTENTIALLY DESTRUCTIVE ENERGY
(a) a diode clamp (usually called a "flyback" or "recirculating diode") across the inductive load, or (b) a Zener-diode clamp to supply or ground, or (c) an RC snubber network.
V CE(sat)
COLLECTOR VOLTAGE
(BR)CBO
Dwg. GP-047-1
Figure 2 - Load Line with Inductive Load
For rapid current decay (fast turn-off speeds), using Zener diodes will raise the flyback voltage during turn-off and improve performance. However, the transient / momentary / peak / spike voltage must not exceed the specified minimum sustaining voltage.
A PRIMER ON ESSENTIALS OF OUTPUT VOLTAGE LIMITATIONS
VZ INDUCTIVE LOAD VF IC
Dwg. EP-058
OUTPUT VOLTAGE
The output voltage ratings of popular Allegro power drivers follows. Some of these sustaining voltage ratings (bold faced) do not presently appear in Allegro data sheets these specifications will be added at the next revisions. Additional assistance pertaining to sustaining voltage issues can be provided by Allegro Applications Engineering.
V CE(SAT) I OUT
OUTPUT CURRENT
ZENER CLAMP DIODE CLAMP
Dwg. WP-001
Figure 3 - "Protected" Inductive Load Driver
Part Number(s) 2064 2065 2068 2069 2540 2543 2544 2547 2549 and 2559 2580
Min. VOUT(SUS), VCE(SUS), or VCE(sus) 35 50 35 50 50 35 50 40 40 35
Internal clamp diodes yes yes yes yes yes yes yes no yes yes
A PRIMER ON ESSENTIALS OF OUTPUT VOLTAGE LIMITATIONS
Part Number 2585 2588 2596 and 2597 2878 and 2878-2 2879
2916, 2917, 2918, and 2919 2936 and 2936-120 2944 2961 2962 2981 and 2982 2983 and 2984 2985 2987 2998 3625 Hall 3626 Hall 3952 and 3953 3961 3962 5140 Hall 5275 Hall 5800 and 5801 5804 5821 5829 5841 5842 5890 5891 5895 7003 8902 8925
Maximum allowable supply voltage is specified higher. Listed here is maximum useful operating voltage defined by an internal overvoltage shutdown or current limiting.
A PRIMER ON ESSENTIALS OF OUTPUT VOLTAGE LIMITATIONS
Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of its products. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use nor for any infringements of patents or other rights of third parties which may result from its use.
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