SUMMIT SMS1242S, SMS1242S-A, SMS1242S-B, SMS1242S-C, SMS1242S-D Datasheet
...
SUMMIT
MICROELECTRONICS, Inc.
2.5V, 3V, 3.3V & 5V Dual Voltage, Dual Reset
Microprocessor Supervisory Circuits
SMS1242
FEATURES
• Supply voltage monitor
- Nominal V
of 2.45V, 2.65V, 2.95V, 4.45V,
RST
4.55V or 4.65V
- RESET# Outputs Guaranteed true at VCC = 1V
- 150ms Reset Delay Time
• Second voltage monitor
-V
SENSE
Input
- 1.25V threshold ±1%
• Manual Reset Input
• Includes 16k-bits nonvolatile memory
- Industry standard 2-wire serial interface
FUNCTIONAL BLOCK DIAGRAM
V
CC
8
OVERVIEW
The SMS1242 microprocessor supervisory circuit reduces the complexity and number of components required
to monitor the supply voltage in +5V, +3V and +2.5V
systems. The SMS1242 will significantly improve system
reliability and accuracy when compared to implementing
the same functions with discrete components.
The SMS1242 provides reset output during power-up,
power-down, and brown-out conditions. It has a 1.25V
threshold input detector for power-fail warning, low battery
detection, or monitoring a secondary power supply. The
part also integrates a separate active low manual reset
input.
It also has 16k-bits of nonvolatile memory accessible over
an industry standard 2-wire serial interface.
V
SENSE
SCL
SDA
6
5
3
1.25V
4
GND
+
–
V
TRIP
+
–
NONVOLATILE
MEMORY
ARRAY
RESET
GENERATOR
7
2
1
2038 BD 2.0
MR#
RESET1#
RESET2#
© SUMMIT MICROELECTRONICS, Inc. 2000 • 300 Orchard City Drive, Suite 131 • Campbell, CA 95008 • Phone 408-378-6461 • Fax 408-378-6586 • www.summitmicro.com
2038 2.0 6/8/00
Characteristics subject to change without notice
1
SMS1242
ABSOLUTE MAXIMUM RATINGS*
Temperature Under Bias –55°C to 125°C
Storage Temperature –65°C to 150°C
Terminal Voltage (With Respect to Ground)–0.3V to 6V
Lead Solder Temperature (10 secs) 300°C
lobmySretemaraPsnoitidnoC.niM.pyT.xaMstinU
V
CC
I
CC
V
TSR
tnerrucylppuS
dlohserhtteseR
egatlovylppusgnitarepO15.5V
<V6.3V
>V6.3V
*COMMENT
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. These are stress
ratings only, and functional operation of the device at these or
any other conditions outside those listed in the operation sections of this specification is not implied. Exposure to any absolute maximum rating for extended periods may affect device
performance and reliability.
5.5<V 5205Aµ
CC
CC
5205Aµ
)ylno3421SMS(sseccayromeM3Am
AnoitpoeciveD573.4524.4574.4V
BnoitpoeciveD526.4576.4527.4V
CnoitpoeciveD524.4574.4525.4V
DnoitpoeciveD524.2054.2574.2V
EnoitpoeciveD526.2056.2576.2V
FnoitpoeciveD529.2059.2579.2V
V
t
V
I
t
V
V
V
V
V
TSYH
TSR
LO
RM
RM
LI
HI
SNS
CC
TSR
V
ESNES
sisiretsyH 05Vm
htdiweslupteseR001051002sm
V,Am2.1=
I
egatlovwoltuptuo#1TESER
KNIS
I
KNIS
V=
CC
V,Aµ002=
CC
.nim3.0V
TSR
V2.1=3.0V
tnerrucpullup#RM 001Aµ
htdiweslup#RM05sn
dlohserhttupni#RM 6.0V
dlohserhttupni#RM7.0 × V
dlohserhttupniV
I
egatlovwoltuptuo#2TESER
I
=V
CC
KNIS
KNIS
V,.nim
TSR
V,Am2.1=
V=
CC
V,Aµ002=
CC
gnillaf02.152.103.1V
ESNES
.nim3.0V
TSR
V2.1=4.0V
CC
2038 Elect Table 2.0
V
2
2038 2.0 6/8/00SUMMIT MICROELECTRONICS, Inc.
SMS1242
PIN NAMES
niPlangiSnoitcnuF
1#1TESER
2#2TESER
3V
4DNGdnuorG
5DNG/ADSdnuorgro,O/IataD3421SMS
6DNG/LCSdnuorgro,kcolCataD3421SMS
7#RMsteseRroftupnilaunaM
8V
ESNES
CC
ro;dloV
CC
steseR
:ybwolnevirDV
ESNES
ESNES
ro,V
retfasm051rofwolV
.dlohserhtevobasi,#RMdna
noitcennocniard
egatlovylppuS
2038 Pin Table 2.0
PIN CONFIGURATION
8-Pin SOIC
.pullupkaewhtiwtuptuowolevitcA
-hserhtwoleb
elihwdlohserhtwoleb
sniameR.dlohserhtwolebsi#RM
CC
RESET1#
RESET2#
V
SENSE
GND
nepotpecxe,#1teseRsaemaS
ehtroftupnirotceteddlohserhT
1
2
3
4
V
8
7
6
5
CC
MR#
SCL
SDA
2038 T PCon 2.0
V
CC
RESET#
MR#
V
SENSE
V
RST
V
RST
t
RST
V
V
IL
t
MR
IH
t
RST
Figure 1. Reset Waveforms
V
SNS
t
RST
2038 T Fig01 2.0
2038 2.0 6/8/00
SUMMIT MICROELECTRONICS, Inc.
3
4.5
4.4
4.3
4.2
4.1
4.0
GLITCH AMPLITUDE (V)
3.9
SMS1242
V
RST
0V
0V
3.8
02
31
4
PULSE WIDTH (ms)
6
75
Figure 2. Supply Voltage Noise Rejection, V
2V
V
CC
RESET#
500ms/Div.
1.25V
0V
V
CC
0V
108
9
2038 Fig02 2.0
=4.55V, TA = 25ºC
RST
V
SENSE
RESET#
Figure 3. RESET Output vs. Supply
4
Figure 4. RESET Output vs. V
SENSE
2038 2.0 6/8/00SUMMIT MICROELECTRONICS, Inc.
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