 STM6904 Product
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STM6905 Product
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ST is expanding its range of analog circuitry with the introduction of two multiple voltage supervisors that provide monitoring of 4 and 5 power supply voltages.
Today’s system designs often have several processors, ASICs or FPGAs, and these complex ICs use more than one voltage supply, such as for the core and I/O. These systems now have more than three voltages. Today’s supervisors need to monitor the multiple voltages to properly supervise the entire system and ST’s new STM6904 and STM6905 meet this need.
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The STM6905 monitors 5 voltages while the STM6904 monitors 4. Both parts have 2 fixed voltages that are set at the factory and many possible voltage combinations are possible. The other 2 or 3 voltages are adjustable by the system designer. Voltage thresholds range from 1.050 V to 3.078 V with a very tight accuracy of +/- 1.8 % across the full temperature and voltage range. Accuracy is +/- 1 % at 25 °C, and the parts have a very low supply current of 12 μA typical. A push-button or manual reset input (MR) is also available. If any of the four or five monitored voltages drops below its factory-trimmed or adjustable thresholds, or if the MR is asserted to logic low, the reset output (RST) is asserted (driven low). Once asserted, RST is maintained Low for a minimum delay period (trec) after ALL monitored supplies rise above their respective thresholds and MR returns to High.
Both parts have options in the reset delay time period (trec). The initial parts available have a 210 ms trec. The STM6904 has a dedicated trec select pin so the user can select between 210 ms or 420 ms. Different fixed reset thresholds and trec times are available upon request.
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Part
number
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Fixed
monitored
voltages
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Adjustable
monitored
voltages
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Manual
reset
input
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Reset
delay
adjust pin |
Package |
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2 |
2 |
Y |
Y |
MSOP-8 |
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2 |
3 |
Y |
N |
MSOP-8 |
Target applications include any system with a high-performance processor or peripheral with multiple voltage inputs. For example, ST’s ARM7 products require 3.3 V for VCC-I/O and 1.8 V for VCCCORE, and are perfect matches for the STM690x series supervisors.
STM6904 and STM6905 features |
 Accurate ±1.8% across temperature voltage threshold (±1% at 25 °C)
Primary supply (VCC) monitor. Fixed (factoryprogrammed)
reset thresholds: 3.078 V to
2.866 V
Second fixed (V2IN) monitor. Fixed (factoryprogrammed)
reset thresholds: 2.333 V to 1.050 V
Two or three additional adjustable supply monitor inputs (externally adjustable)
0.6 V internal reference
RST output (open drain)
Output guaranteed for VCC 0.8 V
Reset delay time (trec) pin selectable (STM6904)
Manual reset input (MR)
Low supply current of 12 μA (typ)
Power supply voltage 0.8 V to 5.5 V
Housed in the standard 8-lead MSOP (TSSOP)
A typical example of monitoring multiple voltages in
a complex system using STM6904
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