G680HT1F [GMT]
Power Supply Support Circuit, Fixed, 1 Channel, +1.25VV, PDSO5, SOT-23, 5 PIN;
| 型号： | G680HT1F |
| 厂家： | 
GLOBAL MIXED-MODE TECHNOLOGY INC |
| 描述： | Power Supply Support Circuit, Fixed, 1 Channel, +1.25VV, PDSO5, SOT-23, 5 PIN 光电二极管 |
| 文件： | 总7页 (文件大小：218K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Global Mixed-mode Technology Inc.
G680/G681
Microprocessor Reset IC
Features
General Description
High ±2% Voltage Threshold Accuracy
The G680/G681 are microprocessor (µP) supervisory
circuits used to monitor the power supplies in µP and
digital systems. High- and Low- voltage thresholds can
be adjusted independently, allowing for wide hystere-
sis. Voltage detection thresholds are accurate to 2%.
Independently Adjustable High- and Low-
Voltage Thresholds
Fully Specified Over Temperature
Available in Three Output Configurations
Push-Pull RESET Output (G680L)
Push-Pull RESET Output (G680H)
These circuits perform a single function: they assert a
reset signal whenever the VCC supply voltage declines
below the low-voltage threshold, keeping it asserted
for at least 140ms after VCC has risen above the
high-voltage threshold.
Open-Drain RESET Output (G681L)
140ms min Power-On Reset Pulse Width
4µA Supply Current
Power Supply Transient Immunity
5-Pin SOT-23-5 Packages
The G681L has an open-drain output stage, while the
G680 have push-pull outputs. The G681L’s open-drain
RESET output requires a pull-up resistor that can be
connected to a voltage higher than VCC. The G680L
Applications
Computers
have an active-low RESET output, while the G680H
has an active-high RESET output. The reset com-
parator is designed to ignore fast transients on thresh-
old input.
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable / Battery-Powered Equipment
Automotive
The IC’s power supply is separate from the detector
inputs, allowing the G680/G681 to be powered from a
down-stream supply. Low supply current (4µA, typical)
makes the G680/G681 ideal for use in portable
equipment. The G680/G681 are available in 5 pin SOT
-23-5 packages.
Ordering Information
ORDER
NUMBER
G680H(L)T1
G681LT1
ORDER NUMBER
TEMP. RANGE
PIN-PACKAGE
(Pb free)
G680H(L)T1f
G681LT1f
-40°C ~ +105°C
-40°C ~ +105°C
SOT-23-5
SOT-23-5
Pin Configuration
Typical Application Circuit
VCC
HTH
Vcc
1
5
4
VCC
VCC
HTH
RPULL-UP
*
2
3
GND
LTH
µP
G680/G681
SOT-23-5
G680/G681
RESET
RESET
(RESET)
LTH
INPUT
GND
GND
RESET(RESET)
*G681 ONLY
() is for G680H
TEL: 886-3-5788833
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Ver: 1.3
Dec 13, 2004
1
Global Mixed-mode Technology Inc.
G680/G681
Absolute Maximum Ratings
Terminal Voltage (with respect to GND)
Continuous Power Dissipation (TA = +70°C)
VCC.……………………………….…………-0.3V to +6.0V
Input Voltage (VLTH, VHTH)…..…..…-0.3V to (VCC + 0.3V)
SOT23-5…………………………….….………….568mW
Operating Temperature Range......…..-40°C to +105°C
Storage Temperature Range.....….…..-65°C to +150°C
Reflow Temperature (soldering, 10sec)…....……260°C
RESET,RESET (push-pull)....…....-0.3V to (VCC + 0.3V)
RESET (open drain)...….......….......…....-0.3V to +6.0V
Input Current, VCC .........................……................20mA
Output Current, RESET, RESET .…...................20mA
Stresses beyond 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 beyond those indicated in the operational sections of the
specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Electrical Characteristics
(VCC = full range, TA = -40°C to +105°C, unless otherwise noted. Typical values are at TA = +25°C, VCC = 3.3V (Note 1)
PARAMETER
SYMBOL
CONDITION
MIN TYP MAX UNITS
VCC Range
2.5
---
---
4
5.5
7.5
V
µA
Supply Current (SOT23)
Reset Threshold
ICC
VCC<5.5V
VTH
1.23 1.25 1.29
V
Reset Threshold Tempco
VLTH to Reset Delay (Note 2)
---
---
80
---
70
15
---
---
ppm/°C
µs
VLTH = VTH to VTH – 100mV
VCC = 2.5V
250
500
550
---
Reset Active Timeout Period
ms
VCC = 5.5V
VCC = 2.5V, V RESET (VRESET) = 0.5V,RESET
Asserted or RESET not asserted
VCC = 2.5V, V RESET (VRESET) = 2V, RESET
not asserted or RESET asserted.
VHTH(VLTH)=5V
RESET (RESET) Output Current Low
IOL
8
---
---
mA
RESET Output Current High
(push-pull G680)
IOH
2
---
---
mA
µA
HTH, LTH Pin Input Leakage
ILEAK
---
0.1
0.5
Note 1: Production testing done at TA = +25°C; limits over temperature guaranteed by design.
Note 2:RESET output is for G680L/G681L; While RESET output is for G680H.
Selector Guide
PART / SUFFIX
G680LT1
OUTPUT TYPE
Push-pull RESET
Push-pull RESET
Open-Drain RESET
TOP MARK
680Ax
G680HT1
680Bx
G681LT1
681Ax
TEL: 886-3-5788833
http://www.gmt.com.tw
Ver: 1.3
Dec 13, 2004
2
Global Mixed-mode Technology Inc.
G680/G681
Timing Diagram
A
VHTH
VLTH
VBATT
0V
tRST
tRST
VOH
VOL
VRESET
VOH
VOL
VRESET
Propagation delays not shown for clarity.
Functional Diagram
VDD
Low-Voltage Detect
+
LTH
HTH
R
S
Q
Q
RESET
RESET
One Shot
High-Voltage Detect
+
Delay
Line
1.25V
Bandgap
+
Reference
G680/G681
GND
TEL: 886-3-5788833
Ver: 1.3
http://www.gmt.com.tw
Dec 13, 2004
3
Global Mixed-mode Technology Inc.
G680/G681
Typical Operating Characteristics
(VCC = full range, TA = -40°C to +105°C, unless otherwise noted. Typical values are at TA = +25°C, VCC = 5V
for 463/438/400 versions, VCC= 3.3V for 308/293 versions, and VCC = 3V for 263 version.)
Power -Down Reset Delay
vs. Temperature
Supply Current vs.
Temperature
70
60
50
40
30
20
10
0
5
4.5
4
VOD=VTH-VLTH
VOD=10mV
Vcc=5V
3.5
3
Vcc=2.5V
Vcc=3.3V
2.5
2
VOD=100mV
VOD=200mV
1.5
1
0.5
0
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
Temperature (°C)
Temperature(°C)
Normalized Reset Threshold
vs. Temperature
Reset Timeout Period
vs. Temperature
800
700
600
500
400
300
200
100
0
1.002
1
VCC=5.5V
VCC=3V
0.998
0.996
0.994
0.992
0.99
0.988
0.986
-40 -30 -20 -10
0 10 20 27 30 40 50 60 70 80 90
-40 -30 -20 -10
0
10 20 30 40 50 60 70 80 90
Temperature (°C)
Temperature (°C)
TEL: 886-3-5788833
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Ver: 1.3
Dec 13, 2004
4
Global Mixed-mode Technology Inc.
G680/G681
Pin Description
PIN
NAME
FUNCTION
High-Voltage Theshold (Input): Analog input to a comparator. When the level on this pin initially
rises above VTH, the delay generator cycles and the RESET remains low or RESET remains high
for a minimum of 140ms.
1
HTH
2
GND
LTH
Ground
Low-Voltage Threshold (Input): Analog input to a comparator. This is the voltage monitor input
3
assigned to detect a low voltage condition. When the level on this pin falls below VTH
,
RESET or
RESET is asserted and the condition is latched until VHTH > VTH
.
Reset (Output): Push-pull output. This output is asserted and latched when VLTH <VTH, indicating
a low voltage condition. This state remains latched until VHTH > VTH. The polarity of this signal
(active-high or low) is determined by the part number suffix. See ordering information.
Power Supply (Input): Independent supply input for internal circuitry.
RESET (RESET)
VCC
4
5
Detailed Description
Applications Information
A microprocessor’s (µP’s) reset input starts the µP in a
known state. The G681L/G680L/G680H assert reset to
prevent code-execution errors during power-up,
power-down, or brownout conditions. They assert a
reset signal whenever the threshold voltage declines
below VTH, keeping it asserted for at least 140ms after
threshold voltage input has risen above the reset
threshold. The G681L uses an open-drain output, and
the G680L/G680H have a push-pull output stage.
Negative-Going VCC Transients
In addition to issuing a reset to the µP during power-up,
power-down,
and
brownout
conditions,
the
G681L/G680H/G680L are relatively immune to short-
duration negative-going VLTH transients (glitches).
Figure1. shows typical transient duration vs. reset
comparator overdrive, for which the G681L/G680H/
G680L do not generate a reset pulse. The graph was
generated using a negative-going pulse applied to
VLTH, starting 0.1V above the actual reset threshold
and ending below it by the magnitude indicated (reset
comparator overdrive). The graph indicates the maxi-
mum pulse width a negative-going VLTH transient can
have without causing a reset pulse. As the magnitude
of the transient increases (goes farther below the reset
threshold), the maximum allowable pulse width de-
creases. Typically, a VLTH transient that goes 100mV
below the reset threshold and lasts 7µs or less will not
cause a reset pulse. A 0.1µF bypass capacitor
mounted as close as possible to the VLTH pin provides
additional transient immunity.
Connect a pull-up resistor on the G681L’s RESET out-
put to any supply between 0 and 5.5V.
Battery voltage is monitored by a comparator via a
voltage divider network. The divided voltage is com-
pared to an internal reference voltage. When the volt-
age at the LTH input pin drops below the internal ref-
erence voltage, the output is asserted. At this point,
the voltage at HTH is assumed to be below the refer-
ence voltage.
350
300
250
200
150
100
50
Programming the Thresholds
The low-voltage threshold is calculated using:
R1+R2+R3
VBAT (Io) = VREF
R2+R3
The low-voltage threshold is calculated using:
R1+R2+R3
VBAT (hi) = VREF
R3
where, for both equations:
VBAT (hi) = 1.245V
G680
0
1
10
100
1000
Reset Comparator Overdrive, VTH- VLTH (mV)
In order to provide the additional criteria needed to
solve for the resistor values, the resistors can be se-
lected such that they have a given total value, that is,
Figure1. Maximum Transient Duration without
Causing a Reset Pulse vs. Reset Com-
parator Overdrive
R1 + R2 + R3 = RTOTAL
.
TEL: 886-3-5788833
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Ver: 1.3
Dec 13, 2004
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Global Mixed-mode Technology Inc.
G680/G681
A value such as 1MΩ for RTOTAL is a reasonable value
because it draws minimum battery current but has no
measurable effect on accuracy.
Once R3 is determined, the equation for VBAT (lo) can
be used to determine R2. A single lithium-ion cell
should not be discharged below 2.5V. Many applica-
tions limit the drain to 3.1V. Using 3.1V for the V BAT (lo)
threshold allows calculation of the two remaining re-
sistor values.
When working with large resistors, a small amount of
leakage current can cause voltage offsets that de-
grade system accuracy.
1MΩ
VBAT (lo) =3.1V = 1.245
R2+344k
The maximum recommended total resistance from
VBAT to ground is 3MΩ.
R2 = 56kΩ
VBATT
R1 = 1MΩ - R2 - R3
R 1=600kΩ
604k
1%
G680/G681
R1
The accuracy of the resistors can be chosen based
upon the accuracy required by the system.
VCC
LTH
HTH
RESET
RESET
56k
1%
R2
R3
VCC
VCC
VCC
340k
1%
RPULL-UP
µP
G681
RESET MOTOROLA
RESET
INPUT
68HCXX
Figure 2. Example Circuit
GND
GND
Once the desired trip points are determined, set the
VBAT(hi) threshold first.
For example, use a total of 1M = R1 + R2 + R3. For a
typical single-cell lithium ion battery, 3.6V is a good
“high threshold” because at 3.6V the battery is moder-
ately charged. Solving for R3:
Figure 3. Interfacing to µPs with Bidirectional Re
set I/O
Interfacing to µPs with Bidirectional Reset Pins
1MΩ
R3
V
BAT (hi) = 1.245
Since the RESET output on the G681L is open drain,
this device interfaces easily with µPs that have bidirec-
tional reset pins, such as the Motorola 68HC11. Con-
R3 = 344kΩ
necting the µP supervisor’s RESET output directly to
the microcontroller’s (µC’s) RESET pin with a single
pull-up resistor allows either device to assert reset
(Figure 3).
.
TEL: 886-3-5788833
http://www.gmt.com.tw
Ver: 1.3
Dec 13, 2004
6
Global Mixed-mode Technology Inc.
G680/G681
Package Information
C
D
L
H
E
θ1
e1
e
A
A2
A1
b
Note:
1. Package body sizes exclude mold flash protrusions or gate burrs
2. Tolerance ±0.1000 mm (4mil) unless otherwise specified
3. Coplanarity: 0.1000mm
4. Dimension L is measured in gage plane
DIMENSIONS IN MILLIMETERS
SYMBOLS
MIN
1.00
0.00
0.70
0.35
0.10
2.70
1.40
-----
NOM
1.10
MAX
1.30
0.10
0.90
0.50
0.25
3.10
1.80
-----
A
A1
A2
b
-----
0.80
0.40
C
0.15
D
2.90
E
1.60
e
1.90(TYP)
0.95
e1
H
-----
-----
2.60
0.37
1º
2.80
3.00
-----
L
------
5º
θ1
9º
Taping Specification
PACKAGE
Q’TY/REEL
SOT-23-5
3,000 ea
Feed Direction
SOT-23-5 Package Orientation
GMT Inc. does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and GMT Inc. reserves the right at any time without notice to change said circuitry and specifications.
TEL: 886-3-5788833
http://www.gmt.com.tw
Ver: 1.3
Dec 13, 2004
7
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