SG Micro SGM814 User manual

SGM814/SGM815/SGM816
Ultra-Low Power Voltage Detectors
with Optional Watchdog
SG Micro Corp
www.sg-micro.com
JUNE 2022 –REV. A
GENERAL DESCRIPTION
The SGM814, SGM815 and SGM816 are a family of
complete microprocessor supervisory devices which
combine ultra-low power, supervisory circuits and timer
circuits. System reliability is significantly improved by
such integration compared to the designs using
individual ICs or discrete components. These devices
feature a wide supply voltage from 1V to 5V.
Regardless of whether the detection voltage is high or
low, the output can be forced low through the manual
reset pin (nMR).
If the supply voltage (VDD) exceeds 0.5V during the
power-on period, nRESET will assert low. And when
VDD is under the default voltage threshold, the nRESET
output keeps low. The VHYS design on VDD can avoid
nRESET triggering by mistake.
The SGM814 and SGM815 both have an active-low
open-drain reset output, and can monitor two different
voltages, either PFI or SENSE trigger the threshold, the
nRESET will assert. The SGM816 has an active-low
push-pull reset output and a watchdog timer to monitor
the process.
The devices are available in a Green SOT-23-6
package. They operate over a junction temperature
range of -40℃to +125℃.
FEATURES
●High Accuracy Fixed Detection Options: 1.2V,
1.5V, 1.6V, 2V and 3.3V
●High Trigger Accuracy: 1% (TYP)
●Low Quiescent Current: 1.6μA (TYP)
●Low nRESET Defined Input Voltage: 0.5V
●Delay Time for the Power-on Reset Generator:
140ms
●Reset Output Options:
Open-Drain: SGM814 and SGM815
Push-Pull: SGM816
●Available in a Green SOT-23-6 Package
APPLICATIONS
Microprocessor Systems
Controllers
Battery-Powered Systems
Portable Equipment
Instruments and Apparatus
Communications-Equipment
TYPICAL APPLICATION
SGM815-3.3 DSP
VDD
3.3V
1.6V
nMR
SENSE
nRSTVDD
nRSTSENSE
GND GND
nRESET
V
IO
V
CORE
R
1
R
2
R
3
Figure 1. Typical Application Circuit Example
AVAILABLE OPTIONS
Device nRESET Output
nRSTSENSE,
nRSTVDD Output
nPFO Output WDI Input PFI Input nMR Input SENSE Input
SGM814 √(Open-Drain) √(Open-Drain) √√
SGM815 √(Open-Drain)
√√
SGM816 √(Push-Pull) √√√

SGM814 Ultra-Low Power Voltage Detectors
SGM815/SGM816 with Optional Watchdog
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PACKAGE/ORDERING INFORMATION
MODEL PACKAGE
DESCRIPTION
SPECIFIED
TEMPERATURE
RANGE
ORDERING
NUMBER
PACKAGE
MARKING
PACKING
OPTION
SGM814-1.2 SOT-23-6 -40℃to +125℃SGM814-1.2XN6G/TR G6DXX Tape and Reel, 3000
SGM814-1.5 SOT-23-6 -40℃to +125℃SGM814-1.5XN6G/TR G6GXX Tape and Reel, 3000
SGM814-2.0 SOT-23-6 -40℃to +125℃SGM814-2.0XN6G/TR OU9XX Tape and Reel, 3000
SGM814-3.3 SOT-23-6 -40℃to +125℃SGM814-3.3XN6G/TR G6HXX Tape and Reel, 3000
SGM815-1.6 SOT-23-6 -40℃to +125℃SGM815-1.6XN6G/TR G6IXX Tape and Reel, 3000
SGM815-3.3 SOT-23-6 -40℃to +125℃SGM815-3.3XN6G/TR G5LXX Tape and Reel, 3000
SGM816-1.2 SOT-23-6 -40℃to +125℃SGM816-1.2XN6G/TR SWXXX Tape and Reel, 3000
SGM816-1.5 SOT-23-6 -40℃to +125℃SGM816-1.5XN6G/TR G6LXX Tape and Reel, 3000
SGM816-3.3 SOT-23-6 -40℃to +125℃SGM816-3.3XN6G/TR G6MXX Tape and Reel, 3000
MARKING INFORMATION
NOTE: XX = Date Code.
Date Code - Year
Date Code - Week
Serial Number
YYY XX
Green (RoHS & HSF): SG Micro Corp defines "Green" to mean Pb-Free (RoHS compatible) and free of halogen substances. If
you have additional comments or questions, please contact your SGMICRO representative directly.

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SGM815/SGM816 with Optional Watchdog
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ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VDD............................................. -0.3V to 6V
nMR, nRESET (Push-Pull), VnMR, VnRESET (Push-Pull)
.................................................................-0.3V to VDD + 0.3V
All Other Pins....................................................... -0.3V to 6V
Maximum Low Output Current, IOL ................................ ±5mA
Maximum High Output Current, IOH............................... ±5mA
Input Current, IIK (VSENSE < 0V or VSENSE > VDD).......... ±10mA
Output Current, IOK (VOUT < 0V or VOUT > VDD)(2) ........ ±10mA
Package Thermal Resistance
SOT-23-6, θJA .......................................................... 230℃/W
Junction Temperature.................................................+150℃
Storage Temperature Range ....................... -65℃to +150℃
Lead Temperature (Soldering, 10s) ............................+260℃
ESD Susceptibility
HBM (SGM814, SGM815) ........................................... 1500V
HBM (SGM816) ........................................................... 3000V
CDM ............................................................................ 1000V
NOTES:
1. To ensure the reliable running of the device, the continuous
running time of the device at 5V cannot exceed t = 1000h.
2. For push-pull outputs, the output is clamped by the back
gate diodes inside to the IC, and there is no clamp in the
open-drain outputs.
RECOMMENDED OPERATING CONDITIONS
Supply Voltage, VDD..................................................1V to 5V
SENSE Voltage, VSENSE .......................................... 0V to VDD
WDI
High-level Input Voltage (VIH) at nMR ..........0.8 × VDD (MIN)
Low-level Input Voltage (VIL) at nMR ......... 0.3 × VDD (MAX)
Input Transition Rise and Fall Rates at Δt/ΔV at nMR
..................................................................... 100ns/V (MAX)
nMR, PFI Voltage ................................................... 0V to VDD
Operating Junction Temperature Range...... -40℃to +125℃
OVERSTRESS CAUTION
Stresses beyond those listed in Absolute Maximum Ratings
may cause permanent damage to the device. Exposure
to
absolute maximum rating conditions for extended periods
may affect reliability. Functional operation of the device at any
conditions beyond those indicated in the Recommended
Operating Conditions section
is not implied.
ESD SENSITIVITY CAUTION
This integrated circuit can be damaged if ESD protections are
not considered carefully. SGMICRO recommends that all
integrated circuits be handled with appropriate precautions.
Failure
to observe proper handling and installation procedures
can cause damage. ESD damage can range from subtle
performance
degradation to complete device failure. Precision
integrated circuits may be more susceptible to damage
because even small parametric changes could cause the
device not to meet the published specifications.
DISCLAIMER
SG Micro Corp reserves the right to make any change in
circuit design, or specifications without prior notice.

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SGM815/SGM816 with Optional Watchdog
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PIN CONFIGURATION AND DESCRIPTION
SGM814 (TOP VIEW)
VDD
6
nMR PFI
nRESET
GND
3
2
1
4
nPFO
5
SOT-23-6
Table 1. SGM814 Pin Description
PIN NAME I/O FUNCTION
1 nRESET O Active-Low Open-Drain Reset Output Pin.
2 GND G Ground.
3 nMR I
Manual Reset Input Pin. nRESET keeps low when nMR is low. When nMR is high, nRESET
becomes high after a timeout period. Leave it floating or connect it to VDD if not used.
4 PFI I
Power-Fail Voltage Monitor Input Pin. When PFI is less than 0.551V, nPFO goes low. Connect it
to VDD if not used.
5 nPFO O
Power-Fail Output Pin. Power-fail output goes low and sinks current when PFI is less than
0.551V; otherwise nPFO stays high.
6 VDD I Power Supply Voltage Pin. Monitor the voltage on VDD.
NOTE: I: input, O: output, G: ground.
Table 2. SGM814 Function Table
nMR
V
PFI
> 0.551V
V
DD
> V
IT-
nRESET
nPFO
L 0 X
(1)
L L
L 1 X L H
H 0 0 L L
H 0 1 H L
H 1 0 L H
H 1 1 H H
NOTE:
1. X = Don’t care.

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PIN CONFIGURATION AND DESCRIPTION (continued)
SGM815 (TOP VIEW)
VDD
6
nMR SENSE
nRSTVDD
GND
3
2
1
4
nRSTSENSE5
SOT-23-6
Table 3. SGM815 Pin Description
PIN NAME I/O FUNCTION
1 nRSTVDD O Active-Low Open-Drain Reset Output Pin. The logic level is related to VDD and nMR state.
2 GND G Ground.
3 nMR I
Manual Reset Input Pin. Pull it low to force a reset. nRSTVDD and nRSTSENSE keeps low
when nMR is low. When nMR is high, nRESET becomes high after a timeout period.
Leave it
floating or connect it to VDD if not used.
4 SENSE I
Sense Voltage Pin. If the voltage is below 0.551V, the reset asserts. Connect it to VDD if not
used.
5 nRSTSENSE O
Active-Low Open-Drain Reset Output Pin. The logic level is related to SENSE voltage and
nMR state.
6 VDD I Power Supply Voltage Pin. Monitor the voltage on VDD.
NOTE: I: input, O: output, G: ground.
Table 4. SGM815 Function Table
nMR
V
SENSE
> 0.551V
V
DD
> V
IT-
nRSTVDD
nRSTSENSE
L X
(1)
X L L
H 0 0 L L
H 0 1 H L
H 1 0 L H
H 1 1 H H
NOTE:
1. X = Don’t care.

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SGM815/SGM816 with Optional Watchdog
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PIN CONFIGURATION AND DESCRIPTION (continued)
SGM816 (TOP VIEW)
VDD
6
nMR SENSE
nRESET
GND
3
2
1
4
WDI
5
SOT-23-6
Table 5. SGM816 Pin Description
PIN NAME I/O FUNCTION
1 nRESET O Active-Low Push-Pull Reset Output Pin.
2 GND G Ground.
3 nMR I
Manual Reset Input Pin. Pull it low to force a reset. nRESET keeps low when nMR is low.
When nMR is high, nRESET becomes high after a timeout period. Leave it floating
or
connect it to VDD if not used.
4 SENSE I
Sense Voltage Pin. If the voltage is below 0.551V, the reset asserts. Connect it to VDD if not
used.
5 WDI I
Watchdog Timer Input Pin. If the WDI remains high or low for more than the watchdog
timeout period, the watchdog timer expires. The internal watchdog timer is kept clear while a
reset is asserted. The timer is also cleared if the WDI input is changed (on rising or falling
edges).
6 VDD I Power Supply Voltage Pin. Monitor the voltage on VDD.
NOTE: I: input, O: output, G: ground.
Table 6. SGM816 Function Table (1)
nMR
V
SENSE
> 0.551V
V
DD
> V
IT-
nRESET
L X
(2)
X L
H
0
0
L
H 0 1 L
H 1 0 L
H
1
1
H
NOTES:
1. The watchdog timer function is not included.
2. X = Don’t care.

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SGM815/SGM816 with Optional Watchdog
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ELECTRICAL CHARACTERISTICS
(TJ= -40℃to +125℃, typical values are at TJ= +25℃, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
High-Level Output Voltage VOH
VDD = 3.3V, IOH = -3mA
0.8 × VDD
V
VDD = 1.8V, IOH = -2mA
0.8 × VDD
VDD = 1.5V, IOH = -1mA
0.8 × VDD
VDD = 1.2V, IOH = -0.4mA
0.8 × VDD
Low-Level Output Voltage VOL
V
DD
= 3.3V, I
OL
= 3mA
0.3
V
V
DD
= 1.5V, I
OL
= 2mA
0.3
VDD = 1.2V, IOL = 1mA
0.3
VDD = 1V, IOL = 500μA
0.3
Low-Level Output Voltage (nRESET Only)
VOL
VDD = 0.5V, IOL = 5μA
0.1
V
Negative-Going Input Threshold Voltage (1) VIT-
SGM81x-1.2
TJ= +25℃
1.131
1.142
1.154
V
SGM81x-1.5
1.420
1.434
1.449
SGM81x-1.6
1.506
1.521
1.537
SGM81x-2.0
1.825
1.843
1.861
SGM81x-3.3
2.911
2.941
2.971
SGM81x-1.2
TJ= -40℃to +125℃
1.108
1.176
SGM81x-1.5
1.391
1.477
SGM81x-1.6
1.476
1.566
SGM81x-2.0
1.788
1.898
SGM81x-3.3
2.852
3.030
Negative-Going Input Threshold Voltage (1)
(SENSE, PFI) VIT-(S) TJ= +25℃0.534 0.551 0.568 V
TJ= -40℃to +125℃0.523 0.579
Temperature Coefficient of VIT-, PFI, SENSE TKTJ= -40℃to +125℃-0.003 -0.019 %/K
Hysteresis Accuracy at VDD Input
VHYS/VIT-
1.5
%
Hysteresis at SENSE, PFI Input
VHYS(S)
VDD ≥1V
15
mV
High-Level Input Current (nMR)
IIH
nMR = VDD, VDD = 3.3V
-50
50
nA
High-Level Input Current (SENSE, PFI)
SENSE, PFI = VDD, VDD = 3.3V
-40
40
High-Level Input Current (WDI)
WDI = VDD, VDD = 3.3V
-60
60
Low-Level Input Current (nMR)
IIL
nMR = 0V, V
DD
= 3.3V
-39
-32
-25
μA
Low-Level Input Current (SENSE, PFI)
SENSE, PFI, WDI = 0V, V
DD
= 3.3V
-30
30
nA
Low-Level Input Current (WDI)
WDI = 0V, VDD = 3.3V
-75
75
High-Level Output Current at nRESET (2)
(Open-Drain)
IOH VDD = VIT-+ 0.2V, VOH = 3.3V 200 nA
Supply Current IDD
V
DD
= 1V
(average current)
TJ= -40℃to +125℃
1.6 4.5
μA
V
DD
= 2V
(average current)
1.7 5
V
DD
= 3.6V
(average current)
1.8 5
V
DD
= 5.0V
(average current)
2 5
Internal Pull-Up Resistor at nMR
R
nMR
70
100
130
kΩ
Input Capacitance at nMR, SENSE, PFI, WDI
C
IN
V
IN
= 0V to V
DD
4
pF
NOTES:
1. Place a 0.1μF bypass capacitor near VDD to ensure the stability of the threshold voltage.
2. Also refers to nRSTVDD and nRSTSENSE.

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TIMING REQUIREMENTS
(At RL= 1MΩ, CL= 50pF and TJ= -40℃to +125℃, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Timeout Period at WDI tT_OUT 0.5 1.2 1.9 s
Pulse Duration at VDD
tW
VIH = 1.1 × VIT-, VIL = 0.9 × VIT-, VIT-= 1.142V 40
μs
Pulse Duration at nMR VDD ≥ VIT-+ 0.2V, VIL = 0.3 × VDD, VIH = 0.8 × VDD 2
Pulse Duration at SENSE VDD ≥ VIT-, VIH = 1.1 × VIT-(S), VIL = 0.9 × VIT-(S) 25
Pulse Duration at PFI VIH = 1.1 × VIT-(S), VIL = 0.9 × VIT-(S) 25
Pulse Duration at WDI VDD ≥ VIT-, VIL = 0.3 × VDD, VIH = 0.7 × VDD 0.2
SWITCHING CHARACTERISTICS
(At RL= 1MΩ, CL= 50pF and TJ= -40℃to +125℃, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Delay Time tDVDD ≥1.1 × VIT-, nMR = 0.8 × VDD, s
ee Timing
Requirements
40 140 250 ms
VDD to nRESET or nRSTVDD Propagation
Delay Time, High-to-Low Level Output
tPHL_VDD VIH = 1.1 × VIT-, VIL = 0.9 × VIT-50 μs
SENSE to nRESET or nRSTSENSE
Propagation Delay Time, High-to-Low Level
Output
tPHL_SENSE VIH = 1.1 × VIT-, VIL = 0.9 × VIT-20 μs
PFI to nPFO Propagation Delay Time,
High-to-Low Level Output
tPHL_nPFO VIH = 1.1 × VIT-, VIL = 0.9 × VIT-20 μs
PFI to nPFO Propagation Delay Time,
Low-to-High Level Output
tPLH_nPFO VIH = 1.1 × VIT-, VIL = 0.9 × VIT-550 μs
nMR to nRESET, nRSTVDD, nRSTSENSE
Propagation Delay Time, High-to-Low Level
Output
tPHL_MR VDD ≥ VIT-, VIL = 0.3 × VDD, VIH = 0.8 × VDD 1 1.5 μs
nRESET
V
DD
V
IT-
Output Condition
Undefined
nMR
0.5V
t
D
t
D
t
D
t
t
t
Output Condition
Undefined
V
IT-
+ V
HYS
Figure 2. nRESET Timing Diagram for SGM814

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SWITCHING CHARACTERISTICS (continued)
PFI
V
IT-(S)
= 0.551V
t
Output Condition
Undefined
t
nPFO
Output Condition
Undefined
V
IT-(S)
+ V
HYS-(S)
Figure 3. nPFO Timing Diagram for SGM814
nRSTSENSE
nRSTVDD
VDD
VIT-
0.5V
Output Condition
Undefined
VIT-(S) = 0.551V
SENSE
t
t
t
t
t
nMR
Output Condition
Undefined
Output Condition
Undefined
Output Condition
Undefined
tDtD
tD
tD
VIT- + VHYS
VIT-(S) + VHYS(S)
Figure 4. Timing Diagram for SGM815

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SWITCHING CHARACTERISTICS (continued)
X
t
t
t
t
t
V
DD
Output Condition
Undefined
t
D
t
D
t
D
t
D
t
D
t
T_OUT
V
IT-
0.5V
V
IT-(S)
= 0.551V
SENSE
nRESET
Output Condition
Undefined
WDI
nMR
X = Don’t care
V
IT-
+ V
HYS
V
IT-(S)
+ V
HYS(S)
Figure 5. Timing Diagram for SGM816

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TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs. Supply Voltage
Output Voltage vs. Supply Voltage
Low-Level Output Voltage vs. Low-Level Output Current
Low-Level Output Voltage vs. Low-Level Output Current
Low-Level Output Voltage vs. Low-Level Output Current
High-Level Output Voltage vs. High-Level Output Current
0
1
2
3
4
5
6
7
00.5 11.5 22.5 33.5 44.5 5
Supply Current (μA)
Supply Voltage (V)
TJ= -40℃
TJ= 0℃
TJ= +25℃
TJ= +85℃
TJ= +105℃
TJ= +125℃
nMR, nRESET: Open, SENSE = VDD, WDI: triggered
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Output Voltage (V)
Supply Voltage (V)
TJ= -40℃
TJ= 0℃
TJ= +25℃
TJ= +85℃
TJ= +105℃
TJ= +125℃
SGM814-3.3, RPULL = 100kΩ
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Low-Level Output Voltage (V)
Low-Level Output Current (mA)
TJ= -40℃
TJ= 0℃
TJ= +25℃
TJ= +85℃
TJ= +105℃
TJ= +125℃
VDD = 1.2V, SENSE, nMR = GND, WDI: GND
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
012345678910 11 12
Low-Level Output Voltage (V)
Low-Level Output Current (mA)
TJ= -40℃
TJ= 0℃
TJ= +25℃
TJ= +85℃
TJ= +105℃
TJ= +125℃
VDD = 3.3V, SENSE, nMR = GND, WDI: GND
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0246810 12 14
Low-Level Output Voltage (V)
Low-Level Output Current (mA)
TJ= -40℃
TJ= 0℃
TJ= +25℃
TJ= +85℃
TJ= +105℃
TJ= +125℃
VDD = 5.0V, SENSE, nMR = GND, WDI: GND
1.10
1.12
1.14
1.16
1.18
1.20
1.22
00.1 0.2 0.3 0.4 0.5
High-Level Output Voltage (V)
High-Level Output Current (mA)
TJ= -40℃
TJ= 0℃
TJ= +25℃
TJ= +85℃
TJ= +105℃
TJ= +125℃
VDD = 1.2V, SENSE, nMR = VDD, WDI: triggered

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)
High-Level Output Voltage vs. High-Level Output Current
High-Level Output Voltage vs. High-Level Output Current
Minimum Pulse Duration at VDD vs. Threshold Overdrive Voltage
VDD Normalized Threshold Voltage vs. Temperature
Hysteresis Accuracy at VDD Input vs. Temperature
SENSE, FPI Threshold Voltage vs. Temperature
2.8
2.9
3.0
3.1
3.2
3.3
3.4
0246810
High-Level Output Voltage (V)
High-Level Output Current (mA)
TJ= -40℃
TJ= 0℃
TJ= +25℃
TJ= +85℃
TJ= +105℃
TJ= +125℃
VDD = 3.3V, SENSE, nMR = VDD, WDI: triggered
4.6
4.7
4.8
4.9
5.0
5.1
0246810
High-Level Output Voltage (V)
High-Level Output Current (mA)
TJ= -40℃
TJ= 0℃
TJ= +25℃
TJ= +85℃
TJ= +105℃
TJ= +125℃
VDD = 5V, SENSE, nMR = VDD, WDI: triggered
0
10
20
30
40
50
00.1 0.2 0.3 0.4 0.5
Minimum Pulse Duration at VDD (μs)
Threshold Overdrive Voltage (V)
nMR Open, SENSE = VDD
VDD = 3.3V
VDD = 1.2V
0.995
0.996
0.997
0.998
0.999
1.000
1.001
1.002
1.003
1.004
1.005
-40 -25 -10 520 35 50 65 80 95 110 125
VDD Normalized Threshold Voltage (V)
Temperature (℃)
1.360
1.365
1.370
1.375
1.380
1.385
1.390
1.395
1.400
1.405
1.410
-40 -25 -10 520 35 50 65 80 95 110 125
Hysteresis Accuracy at VDD Input (%)
Temperature (℃)
551.0
551.2
551.4
551.6
551.8
552.0
552.2
552.4
-40 -25 -10 520 35 50 65 80 95 110 125
SENSE, PFI Threshold Voltage (mV)
Temperature (℃)

SGM814 Ultra-Low Power Voltage Detectors
SGM815/SGM816 with Optional Watchdog
13
JUNE 2022
SG Micro Corp
www.sg-micro.com
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
Hysteresis at SENSE, FPI Input vs. Temperature
Delay Time vs. Temperature
11
12
13
14
15
16
17
18
19
20
21
22
-40 -25 -10 520 35 50 65 80 95 110 125
Hysteresis at SENSE, PFI Input (mV)
Temperature (℃)
120
125
130
135
140
145
150
155
160
-40 -25 -10 520 35 50 65 80 95 110 125
Delay Time (ms)
Temperature (℃)

SGM814 Ultra-Low Power Voltage Detectors
SGM815/SGM816 with Optional Watchdog
14
JUNE 2022
SG Micro Corp
www.sg-micro.com
FUNCTIONAL BLOCK DIAGRAMS
+
+
Reset Logic
and Timer
VDD
nMR
PFI
VREF = 0.551V
nRESET
nPFO
Voltage
Reference
GND
Voltage
Reference
Figure 6. SGM814 Block Diagram
+
+
Reset Logic
and Timer
VDD
nMR
SENSE
VREF = 0.551V
Voltage
Reference
GND
Voltage
Reference
nRSTSENSE
nRSTVDD
Figure 7. SGM815 Block Diagram
+
+
Reset Logic
and Timer
VDD
nMR
SENSE
V
REF
= 0.551V
Voltage
Reference
GND
Voltage
Reference nRESET
V
DD
WDI Watchdog Logic
and Control
Figure 8. SGM816 Block Diagram

SGM814 Ultra-Low Power Voltage Detectors
SGM815/SGM816 with Optional Watchdog
15
JUNE 2022
SG Micro Corp
www.sg-micro.com
DETAILED DESCRIPTION
Manual Reset (nMR)
The manual reset (nMR) input allows the operator, test
technician, or external logic circuit to initiate a reset. A
logic low on nMR forces the nRESET low. After nMR
returns to a logic high, nRESET is deasserted after a
reset delay time period (tD). nMR is pulled up to VDD
with an internal 100kΩ resistor. This pin can be floating
if nMR is not used. It is recommended to connect a
0.1μF capacitor between nMR pin and GND to reduce
ambient noise interference.
PFI, nPFO (SGM814 Only)
For SGM814, PFI (Power-Fail Input) and nPFO
(Power-Fail Open-Drain Output) pins can be used for
power-fail warning or monitoring a power supply other
than the device power supply, and doesn’t affect
nRESET pin.
The internal voltage reference (0.551V) is used for
compare with PFI pin, once the PFI voltage is lower
than the negative-going input threshold voltage (VIT-(S)),
the nPFO goes low. Once PFI voltage exceeds 0.551V
plus a hysteresis of about 15mV, the output goes high.
Connecting a resistor divider externally can monitor any
voltage above 0.551V.
To assure the PFI pin leakage current compared with
the current through the resistor divider can be
neglected and minimize the resistor power
consumption, the sum of two resistors should be about
1MΩ. To ensure the accuracy of the detection voltage,
the tolerance of the external resistor should be less
than 1%. It is recommended to leave nPFO floating and
connect PFI to VDD if the PFI comparator is not used.
SENSE (SGM815 and SGM816 Only)
A 0.551V reference voltage is intergraded in sense
block, then the voltage at SENSE input will compare
with it. If the SENSE voltage falls below VIT-(S), the
nRESET goes low. For the SGM815, there is a
dedicated nRSTSENSE output. For the SGM816, the
logic signal of SENSE is OR-wired with the signal of
VDD or nMR. Once the sensed voltage exceeds
0.551V plus a hysteresis of about 15mV, the output
returns to the inactive state after a fixed delay by the
internal timer.
Watchdog (SGM816 Only)
A watchdog timer is integrated in SGM816 only. It must
be periodically triggered by a rising edge or a falling
edge of WDI. If the monitoring system cannot retrigger
the watchdog circuit during the timeout period, the
nRESET becomes active within the tDperiod, which will
also clear the watchdog timer.

SGM814 Ultra-Low Power Voltage Detectors
SGM815/SGM816 with Optional Watchdog
16
JUNE 2022
SG Micro Corp
www.sg-micro.com
APPLICATION INFORMATION
The SGM814, SGM815 and SGM816 are excellent
voltage detectors that integrate a manual reset pin. The
SGM814 and SGM815 have an active-low open-drain
reset output, and the SGM816 has an active-low
push-pull reset output. For the SGM814, the PFI and its
corresponding nPFO can be used to monitor power
supplies other than the input power supply. It also has a
short delay time that can realize more direct trigger
output. While the SGM815 has a SENSE input and
corresponding output (nRSTSENSE) to monitor two
different voltages, and its delay time is longer than the
SGM814 which can reduce accidental triggering of the
output. The SGM816 features a watchdog timer to
monitor the running of the microprocessor.
SGM814-1.2
VDD
nMR
PFI nRESET
GND
R
1
R
2
R
3
Reset Output
2-Cell
NiMH
nPFO
Figure 9. Battery Monitoring with Low Supply Current
Design Requirements
Both the SGM814 and SGM815 are suitable for some
applications that need low quiescent current during the
reset period. The SGM815 has two reset outputs,
nRSTVDD and nRSTSENSE, which are triggered by
the monitoring result of VDD voltage and the monitoring
result of SENSE voltage respectively. The SGM814-1.2
used to monitor the input voltage of battery is shown in
Figure 9. The threshold voltage VIT- is 1.142V. Select
low VIT- to ensure the supply voltage higher than the
VDD threshold voltage. And the battery voltage can be
monitored by the SENSE pin.
Detailed Design Process
The voltage divider can be calculated by Equation 1,
asserting a reset using the nRSTSENSE output at 2 ×
0.8V = 1.6V.
TRIP
12
IT-(S)
V
R R -1
V

= ×


(1)
where:
VTRIP is the battery voltage when a reset is asserted.
VIT-(S) is the SENSE threshold voltage (0.551V).
R1is selected for a resistor current within 1μA.
When VTRIP is 1.6V, R1is 1.9 × R2. Therefore, R1is
820kΩ and R2is 430kΩ.
Power Supply Recommendations
The devices operate with a wide input range from 1V to
5V. A 0.1μF ceramic capacitor is recommended
between the VDD and GND pin to reduce the input
supply noise.
Typical Application Example
SGM814-2.0 DSP
Analog
Circuit
nMR
PFI nRESET
nPFO
GND
VDD
nRESET
VDD
Py.x
GND
V
IN+
V
IN-
R
1
R
2
Px.x
R
3
R
4
( )
−
=
2
TH _ VIN DD
1
R
V 0.551V - V - 0.551V
R
(2)
NOTE: 1. R3and R4can be integrated in a microcontroller.
Figure 10. SGM814 Monitoring a Negative Voltage
SGM816-3.3
VDD
3.3V
1.5V
nMR
SENSE
nRESET
WDI
GND GND
nRESET
DSP
V
IO
V
CORE
R
1
R
2
Px.y
+
= × 12
TH _ CORE
2
RR
V 0.551V R
(3)
Figure 11. SGM816 in a DSP-System Monitoring Both
Supply Voltages

SGM814 Ultra-Low Power Voltage Detectors
SGM815/SGM816 with Optional Watchdog
17
JUNE 2022
SG Micro Corp
www.sg-micro.com
APPLICATION INFORMATION (continued)
Layout
It is recommended to connect the VDD decoupling
capacitor to the device as close as possible. Use short
and wide PCB traces for the VDD supply node.
Because the trace between VDD and the capacitor will
form parasitic inductance, then the parasitic inductance
and the VDD capacitor will form an LC resonant circuit
which will cause a ringing with peak voltages higher
than the maximum VDD value.
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Original (MAY 2022) to REV.A Page
Changed from product preview to production data............................................................................................................................................. All

PACKAGE INFORMATION
TX00034.001
SG Micro Corp
www.sg-micro.com
PACKAGE OUTLINE DIMENSIONS
SOT-23-6
Symbol
Dimensions In Millimeters
MIN
MOD
MAX
A - - 1.450
A1 0.000 - 0.150
A2 0.900 - 1.300
b
0.300
-
0.500
c
0.080
-
0.220
D 2.750 - 3.050
E 1.450 - 1.750
E1
2.600
-
3.000
e 0.950 BSC
e1 1.900 BSC
L 0.300 - 0.600
θ0° - 8°
ccc 0.100
NOTES:
1. This drawing is subject to change without notice.
2. The dimensions do not include mold flashes, protrusions or gate burrs.
3. Reference JEDEC MO-178.
E
E1
e
e1
b
D
A1
A2
c
L
θ
0.25
2.59
0.99
0.95
0.69
RECOMMENDED LAND PATTERN (Unit: mm)
ccc C
SEATING PLANE
C
A

PACKAGE INFORMATION
TX10000.000
SG Micro Corp
www.sg-micro.com
TAPE AND REEL INFORMATION
NOTE: The picture is only for reference. Please make the object as the standard.
KEY PARAMETER LIST OF TAPE AND REEL
Package Type Reel
Diameter
Reel Width
W1
(mm)
A0
(mm)
B0
(mm)
K0
(mm)
P0
(mm)
P1
(mm)
P2
(mm)
W
(mm)
Pin1
Quadrant
DD0001
SOT-23-6 7″ 9.5 3.17 3.23 1.37 4.0 4.0 2.0 8.0 Q3
Reel Width (W1)
Reel Diameter
REEL DIMENSIONS
TAPE DIMENSIONS
DIRECTION OF FEED
P2 P0
W
P1 A0 K0
B0
Q1 Q2
Q4
Q3 Q3 Q4
Q2
Q1
Q3 Q4
Q2
Q1

PACKAGE INFORMATION
TX20000.000
SG Micro Corp
www.sg-micro.com
CARTON BOX DIMENSIONS
NOTE: The picture is only for reference. Please make the object as the standard.
KEY PARAMETER LIST OF CARTON BOX
Reel Type Length
(mm)
Width
(mm)
Height
(mm) Pizza/Carton
DD0002
7″ (Option) 368 227 224 8
7″ 442 410 224 18