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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 (P) supervisory circuits used to monitor the power supplies in P 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 VCC supply voltage declines below a preset threshold, with hysteresis after VCC 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 VCC. The G684L have an active-low RESET output, while the G684H has an active-high RESET output. The reset comparator is designed to ignore fast transients on VCC, and the outputs are guaranteed to be in the correct logic state for VCC down to 0.8V. Low supply current makes the G684/G685 ideal for use in portable equipment. The G684/G685 are available 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) 14A Supply Current Guaranteed Reset Valid to VCC = 0.8V Power Supply Transient Immunity 5 pin SOT23-5 Packages 2% Threshold Accuracy
Applications
Computers Controllers Intelligent Instruments Critical P and C Power Monitoring Portable / Battery-Powered Equipment Automotive
Ordering Information
ORDER NUMBER TEMP. RANGE
G684H(L)xxxT1U G685LxxxT1U -40C ~ +105C -40C ~ +105C
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
VCC
N.C.
VCC VCC Rpull-up* VCC
GND
2
G684/G685
G684/G685
RESET (RESET)
P
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
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Global Mixed-mode Technology Inc.
Absolute Maximum Ratings
Terminal Voltage (with respect to GND) VCC..................................................-0.3V to +6.0V Delay Capacitor Pin Voltage, VCD.....-0.3 to (VCC +0.3V) 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
G684/G685
Continuous Power Dissipation (TA = +70C) 5-Pin SOT23-5 (derate 2.17mW/C above +70C).174mW Operating Temperature Range ...........-40C to +105C Storage Temperature Range...............-65C to +150C Lead Temperature (soldering, 10s)...................+260C
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 = -40C to +105C, unless otherwise noted. Typical values are at TA = +25C, VCC = 5V for 463/438/400/330 versions, VCC= 3.3V for 308/293 versions, and VCC = 3V for 263 version.) (Note 1) PARAMETER
VCC Range Supply Current (SOT23-5) ICC
SYMBOL
CONDITION
TA = 0C +70C TA = -40C +105C VCC<5.5V, G68_ _463/438/400/330_ VCC<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 A
Reset Threshold
VTH-
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)
VHYS VCC from 0V to 5V IOL VCC = 2.5V, V RESET = 0.5V VCC = 5V, V RESET = 4.5V, G684L463/438/400/330 VCC = 3.3V, V RESET = 2.8V, G684L308/293 VCC = 3V, V RESET = 2.5V, G684L263 VCC = 5V, VRESET = 0.5V, G684H463/438/400/330 VCC = 3.3V, VRESET = 0.5V, G684H308/293 VCC = 3V, VRESET = 0.5V, G684H263 VCC = 2.5V, VRESET = 2V VCC > VTH, RESET deasserted
% ppm/C ms mA
4.5 3 2 16 12 10 2 ---
-----------------
--------------1 mA A mA mA
RESET Output Current High (push-pull active low, G684L)
IOH
RESET Output Current Low (push-pull active high, G684H)
IOL
RESET Output Current High (push-pull active high, G684H)
RESET Open-Drain Output Leakage Current (G685L)
IOH
Note 1: Production testing done at TA = +25C; limits over temperature guaranteed by design.
Ver: 1.2 Jun 03, 2004
TEL: 886-3-5788833 http://www.gmt.com.tw
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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
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Global Mixed-mode Technology Inc.
Typical Operating Characteristics
G684/G685
(VCC = full range, TA = -40C to +105C, unless otherwise noted. Typical values are at TA = +25C, VCC = 5V for 463/438/400/330 versions, VCC= 3.3V for 308/293 versions, and VCC = 3V for 263 version.)
Supply Current vs. VCC
8 7 6
Supply Curremt vs. Temperature (No Load)
7
VCC=5V
6
Supply Current (A)
Supply Current (A)
5 4
VCC=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
VCC=2.5V
3 2 1 0
VCC (V)
-40
-20
0
20
40
60
80
Temperature (C)
Normalized Reset Threshold vs. Temperature
1.06
Normalized Ormalized V TH+, VTH- (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
VT
VTH
TA, Ambient Temperature (C)
Functional Diagram
5 VCC 5 VCC 4 RESET
RD
+
4
RD
+
VTH
*
RESET (RESET)
VTH
2 GND () is for G684H
2
GND
Figure 1
Ver: 1.2 Jun 03, 2004
TEL: 886-3-5788833 http://www.gmt.com.tw
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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 VCC is below the reset threshold, and for 2ms typical after VCC rises above the reset threshold. RESET Output remains high while VCC is below the reset threshold, and for 2ms typical after VCC rises above the reset threshold.
RESET (G684H)
VCC
Supply Voltage (+5V, +3.3V, +3.0V)
Detailed Description
A microprocessor's (P's) reset input starts the P 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 VCC supply voltage declines below a preset threshold (VTH-), VCC has risen above the high reset threshold VTH+ (VTH-+VHYS). 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 VCC = 0 When VCC falls below 0.8V, the G684 RESET output no longer sinks current--it becomes an open circuit. Therefore, high-impedance CMOS logic inputs connected to RESET can drift to undetermined voltages. This presents no problem in most applications since most P and other circuitry is inoperative with VCC below 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; 100k is large enough not to load RESET and small enough to pull RESET to ground. A 100k pull-up resistor to VCC is also recommended for the G685L if RESET is required to remain valid for VCC < 0.8V.
VCC
G684
RESET
GND
R1 100k
Figure2. RESET Valid to VCC = Ground Circuit
Ver: 1.2 Jun 03, 2004
TEL: 886-3-5788833 http://www.gmt.com.tw
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Global Mixed-mode Technology Inc.
Interfacing to Ps with Bidirectional Reset Pins Since the RESET output on the G685L is open drain, this device interfaces easily with Ps that have bidirectional reset pins, such as the Motorola 68HC11. Connecting the P supervisor's RESET output directly to the microcontroller's (C's) RESET pin with a single pull-up resistor allows either device to assert reset (Figure 3).
G684/G685
+5.0V +5.0 VCC RPULL-UP
+3.3V
VCC
G685
RESET
5V SYSTEM
RESET INPUT
VCC
GND
VCC RPULL-UP VCC
GND
G685
RESET
P
RESET MOTOROLA INPUT 68HCXX
Figure 4. G685L Open-Drain RESET Output Allows Use with Multiple Supplies
GND
GND
Figure 3. Interfacing to Ps with Bidirectional Reset I/O G685L Open-Drain RESET Output Allows Use with Multiple Supplies Generally, the pull-up connected to the G685L will connect to the supply voltage that is being monitored at the IC's VCC pin. However, some systems may use the open-drain output to level-shift from the monitored supply to reset circuitry powered by some other supply (Figure 4). Note that as the G685L's VCC decreases below 1V, so does the IC's ability to sink current at RESET . Also, with any pull-up, RESET will be pulled high as VCC decays toward 0. The voltage where this occurs depends on the pull-up resistor value and the voltage to which it is connected.
Benefits of Highly Accurate Reset Threshold Most P supervisor ICs have reset threshold voltages between 5% and 10% below the value of nominal supply voltages. This ensures a reset will not occur within 5% of the nominal supply, but will occur when the supply is 10% below nominal. When using ICs rated at only the nominal supply 5%, this leaves a zone of uncertainty where the supply is between 5% and 10% low, and where the reset may or may not be asserted. The G68_ _463/G68_ _308 use highly accurate circuitry to ensure that reset is asserted close to the 5% limit, and long before the supply has declined to 10% below nominal.
Ver: 1.2 Jun 03, 2004
TEL: 886-3-5788833 http://www.gmt.com.tw
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Global Mixed-mode Technology Inc.
Package Information
G684/G685
C L
D
E
H
e1 e
1
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 SYMBOLS
A A1 A2 b C D E e e1 H L 1
MIN
1.00 0.00 0.70 0.35 0.10 2.70 1.40 --------2.60 0.37 1
DIMENSIONS IN MILLIMETERS NOM
1.10 ----0.80 0.40 0.15 2.90 1.60 1.90(TYP) 0.95 2.80 -----5
MAX
1.30 0.10 0.90 0.50 0.25 3.10 1.80 --------3.00 ----9
Taping Specification
Feed Direction SOT23-5 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.
Ver: 1.2 Jun 03, 2004
TEL: 886-3-5788833 http://www.gmt.com.tw
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