Global Mixed-mode Technology Inc.
G684/G685
Microprocessor Reset IC
Features
Precision Monitoring of +3V, +3.3V, and +5V
Power-Supply Voltages
General Description
The G684/G685 are microprocessor (µP) supervisory
circuits used to monitor the power supplies in µP and
digital systems. They provide excellent circuit reliability
and low cost and adjustments when used with +5V,
+3.3V, +3.0V- powered circuits.
These circuits perform a single function: they assert a
reset signal whenever the V
CC
supply voltage declines
below a preset threshold, with hysteresis after V
CC
has
risen above the reset threshold. Reset thresholds
suitable for operation with a variety of supply voltages
are available.
The G685 has an open-drain output stage, while the
G684 have push-pull outputs. The G685L’s open-drain
RESET output requires a pull-up resistor that can be
connected to a voltage higher than V
CC
. The G684L
have an active-low RESET output, while the G684H
has an active-high RESET output. The reset com-
parator is designed to ignore fast transients on V
CC
,
and the outputs are guaranteed to be in the correct
logic state for V
CC
down to 0.8V.
Low supply current makes the G684/G685 ideal for
use in portable equipment. The G684/G685 are avail-
able in 5-pin SOT23-5 packages.
Fully Specified Over Temperature
Available in Three Output Configurations
Push-Pull RESET Output (G684L)
Push-Pull RESET Output (G684H)
Open-Drain RESET Output (G685L)
14µA Supply Current
Guaranteed Reset Valid to V
CC
= 0.8V
Power Supply Transient Immunity
5 pin SOT23-5 Packages
2% Threshold Accuracy
Applications
Computers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable / Battery-Powered Equipment
Automotive
Ordering Information
ORDER NUMBER TEMP. RANGE
G684H(L)xxxT1U
G685LxxxT1U
-40°C ~ +105°C
-40°C ~ +105°C
PACKAGE
SOT23-5
SOT23-5
Note:
T1 : SOT23-5
U : Tape & Reel
* xxx specifies the threshold voltage.
e.g. 263 denotes the 2.63V threshold voltage.
Pin Configuration
1
5
Typical Application Circuit
V
CC
N.C.
VCC
VCC
R
pull-up*
VCC
GND
2
G684/G685
G684/G685
RESET
(RESET)
µP
RESET
INPUT
GND
GND
3
SOT23-5
4
RESET
(RESET)
GND
()is for G684H
*G685 ONLY
Ver: 1.2
Jun 03, 2004
TEL: 886-3-5788833
http://www.gmt.com.tw
1
Global Mixed-mode Technology Inc.
Absolute Maximum Ratings
Terminal Voltage (with respect to GND)
V
CC
.……………………………..…….…….-0.3V to +6.0V
Delay Capacitor Pin Voltage, V
CD
…..-0.3 to (V
CC
+0.3V)
RESET, RESET (push-pull)....…....-0.3V to (V
CC
+ 0.3V)
RESET (open drain)...…......…................-0.3V to +6.0V
Input Current, V
CC
............................…..…............20mA
Output Current, RESET, RESET ......…...............20mA
G684/G685
Continuous Power Dissipation (T
A
= +70°C)
5-Pin SOT23-5 (derate 2.17mW/°C above +70°C).174mW
Operating Temperature Range …...…..-40°C to +105°C
Storage Temperature Range..….…......-65°C to +150°C
Lead Temperature (soldering, 10s)...…...….…...+260°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress rat-
ings 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
(V
CC
= full range, T
A
= -40°C to +105°C, unless otherwise noted. Typical values are at T
A
= +25°C, V
CC
= 5V
for 463/438/400/330 versions, V
CC
= 3.3V for 308/293 versions, and V
CC
= 3V for 263 version.) (Note 1)
PARAMETER
V
CC
Range
Supply Current (SOT23-5)
I
CC
SYMBOL
CONDITION
T
A
= 0°C +70°C
T
A
= -40°C +105°C
V
CC
<5.5V, G68_ _463/438/400/330_
V
CC
<3.6V, G68_ _308/293/263_
G69_ _463_
G69_ _438_
G69_ _400_
G69_ _330_
G69_ _308_
G69_ _293_
G69_ _263_
MIN
0.8
1
---
---
4.50
4.23
3.88
3.25
3.04
2.86
2.59
3.6
---
---
8
TYP MAX
---
---
16.5
13.9
4.60
4.32
3.96
3.30
3.10
2.91
2.64
5.3
70
2
---
5.5
5.5
25
27
4.69
4.40
4.04
3.37
3.16
2.96
2.69
7
---
---
---
UNIT
V
µA
Reset Threshold
V
TH-
V
Reset Threshold Hysterisis
Reset Threshold Tempco
Reset Time Delay
RESET
Output Current Low
(push-pull active low,
and open-drain active-low, G684L
and G685L)
V
HYS
V
CC
from 0V to 5V
I
OL
V
CC
= 2.5V, V
RESET
= 0.5V
V
CC
= 5V, V
RESET
= 4.5V,
G684L463/438/400/330
V
CC
= 3.3V, V
RESET
= 2.8V,
G684L308/293
V
CC
= 3V, V
RESET
= 2.5V,
G684L263
V
CC
= 5V, V
RESET
= 0.5V,
G684H463/438/400/330
V
CC
= 3.3V, V
RESET
= 0.5V,
G684H308/293
V
CC
= 3V, V
RESET
= 0.5V,
G684H263
V
CC
= 2.5V, V
RESET
= 2V
V
CC
> V
TH
,
RESET
deasserted
%
ppm/°C
ms
mA
4.5
3
2
16
12
10
2
---
---
---
---
---
---
---
---
---
---
---
---
---
---
---
---
1
mA
µA
mA
mA
RESET
Output Current High
(push-pull active low, G684L)
I
OH
RESET Output Current Low
(push-pull active high, G684H)
I
OL
RESET Output Current High
(push-pull active high, G684H)
RESET
Open-Drain Output Leak-
age Current (G685L)
I
OH
Note 1: Production testing done at T
A
= +25°C; limits over temperature guaranteed by design.
Ver: 1.2
Jun 03, 2004
TEL: 886-3-5788833
http://www.gmt.com.tw
2
Global Mixed-mode Technology Inc.
Selector Guide
PART/SUFFIX
G685L463T1U
G685L438T1U
G685L400T1U
G685L330T1U
G685L308T1U
G685L293T1U
G685L263T1U
G684H463T1U
G684H438T1U
G684H400T1U
G684H330T1U
G684H308T1U
G684H293T1U
G684H263T1U
G684L463T1U
G684L438T1U
G684L400T1U
G684L330T1U
G684L308T1U
G684L293T1U
G684L263T1U
G684/G685
TOP MARK
685Gx
685Fx
685Ex
685Dx
685Cx
685Bx
685Ax
684Lx
684Kx
684Jx
684Nx
684Ix
684Hx
684Gx
684Fx
684Ex
684Dx
684Mx
684Cx
684Bx
684Ax
RESET THRESHOLD (V)
4.63
4.38
4.00
3.30
3.08
2.93
2.63
4.63
4.38
4.00
3.30
3.08
2.93
2.63
4.63
4.38
4.00
3.30
3.08
2.93
2.63
OUTPUT TYPE
Open-Drain
RESET
Open-Drain
RESET
Open-Drain
RESET
Open-Drain
RESET
Open-Drain
RESET
Open-Drain
RESET
Open-Drain
RESET
Push-Pull RESET
Push-Pull RESET
Push-Pull RESET
Push-Pull RESET
Push-Pull RESET
Push-Pull RESET
Push-Pull RESET
Push-Pull
RESET
Push-Pull
RESET
Push-Pull
RESET
Push-Pull
RESET
Push-Pull
RESET
Push-Pull
RESET
Push-Pull
RESET
Ver: 1.2
Jun 03, 2004
TEL: 886-3-5788833
http://www.gmt.com.tw
3
Global Mixed-mode Technology Inc.
Typical Operating Characteristics
G684/G685
(V
CC
= full range, T
A
= -40°C to +105°C, unless otherwise noted. Typical values are at T
A
= +25°C, V
CC
= 5V
for 463/438/400/330 versions, V
CC
= 3.3V for 308/293 versions, and V
CC
= 3V for 263 version.)
Supply Current vs. V
CC
8
7
6
Supply Curremt vs. Temperature (No Load)
7
V
CC
=5V
6
Supply Current (µA)
Supply Current (µA)
5
4
V
CC
=3.3V
5
4
3
2
1
0
0
0.6 1
1.2 1.5 1.8 2.1 2.4 2.7
3
3.2 3.3 3.4 3.5 3.7 3.9
4
4.5
5
5.5 6
V
CC
=2.5V
3
2
1
0
V
CC
(V)
-40
-20
0
20
40
60
80
Temperature (°C)
Normalized Reset Threshold vs. Temperature
1.06
Normalized Ormalized V
TH+
, V
TH-
(V)
1.05
1.04
1.03
1.02
1.01
1
0.99
0.98
0.97
0.96
-40 -30 -20 -10
0
10
20
27
30
40
50
60
70
80
90
V
T
V
TH
T
A
, Ambient Temperature (°C)
Functional Diagram
5
V
CC
5
V
CC
4
RESET
R
D
+
4
R
D
+
V
TH
*
RESET
(RESET)
V
TH
2 GND
() is for G684H
2
GND
Figure 1
Ver: 1.2
Jun 03, 2004
TEL: 886-3-5788833
http://www.gmt.com.tw
4
Global Mixed-mode Technology Inc.
Pin Description
PIN
1
2,3
4
5
G684/G685
NAME
N.C.
GND
RESET
(G684L/G685L)
FUNCTION
No Connection.
Ground
RESET
Output remains low while V
CC
is below the reset threshold, and for 2ms typical after V
CC
rises above the reset threshold.
RESET Output remains high while V
CC
is below the reset threshold, and for 2ms typical after V
CC
rises above the reset threshold.
RESET (G684H)
V
CC
Supply Voltage (+5V, +3.3V, +3.0V)
Detailed Description
A microprocessor’s (µP’s) reset input starts the µP in a
known state. The G685L/G684L/G684H assert reset to
prevent code-execution errors during power-up,
power-down, or brownout conditions. They assert a
reset signal whenever the V
CC
supply voltage declines
below a preset threshold (V
TH-
), V
CC
has risen above
the high reset threshold V
TH+
(V
TH-
+V
HYS
). The G685L
uses an open-drain output, and the G684L/G684H
have a push-pull output stage. Connect a pull-up resistor
on the G685L’s RESET output to any supply between 0
and 5.5V.
Ensuring a Valid Reset Output Down to V
CC
= 0
When V
CC
falls below 0.8V, the G684 RESET output
no longer sinks current—it becomes an open circuit.
Therefore, high-impedance CMOS logic inputs con-
nected to RESET can drift to undetermined voltages.
This presents no problem in most applications since
most µP and other circuitry is inoperative with
VCC
be-
low 0.8V. However, in applications where RESET ust
be valid down to 0V, adding a pull-down resistor to
RESET causes any stray leakage currents to flow to
ground, holding RESET low (Figure 2). R1’s value is
not critical; 100kΩ is large enough not to load RESET
and small enough to pull RESET to ground.
A 100kΩ pull-up resistor to V
CC
is also recommended
for the G685L if RESET is required to remain valid for
V
CC
< 0.8V.
V
CC
G684
RESET
GND
R1
100k
Figure2.
RESET
Valid to V
CC
= Ground Circuit
Ver: 1.2
Jun 03, 2004
TEL: 886-3-5788833
http://www.gmt.com.tw
5
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