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IMP183 4/A/D
POWER MANAGEMENT
Dual 5V and 3.3V P Power Supply Supervisors w/Manual Reset
- Push-Pull and Open-Dr ain Outputs - Select able T r ip Point Toler ance
The IMP1834 supervisors simultaneously monitor both 3.3V and 5V power sources and issue reset signals when either supply is out of tolerance. When an out-of-tolerance condition is detected, the output-reset signal of the affected supply becomes active and resets the system microprocessor/microcontroller. On power-up and after the supply voltage returns to an in-tolerance condition, the reset signal remains active for approximately 350ms. This allows the power supply and system microprocessor to stabilize. The IMP1834 supervisors are pin-compatible with devices from Dallas Semiconductor and require up to 40% less current. Tolerance levels are independently selectable for both supplies. Tolerance options are 5- and 10-percent for the 5V supply and for the 3.3V supply, 10- and 20-percent. The IMP1834 and IMP1834D have push-pull reset output stages. The IMP1834A active LOW reset outputs are open drain devices that can both be connected to either 5 volt or 3.3 volt supply. The IMP1834 and IMP1834A have active LOW reset outputs. The IMP1834D has active HIGH reset outputs. All devices can issue reset signals through an internally debounced pushbutton reset input that affects both reset outputs. All devices operate over the extended industrial temperature range. Devices are available in 8-pin DIP, surface mount 8-pin SO and 8-pin MicroSO packages. Die are also available.
Key Features
x Lower power, pin-compatible replacements for the Dallas DS1834 -- 40% lower maximum supply current: 30A vs 50A x Monitor 5V and 3.3V supplies simultaneously x 5V and 3.3V power-on reset x 350ms reset time x Debounced pushbutton reset input x Push-Pull CMOS output -- IMP1834, IMP1834D -- Eliminates external pull-up resistors -- Active LOW (IMP1834), HIGH (IMP1834D) x Open drain output -- IMP1834A -- Active LOW x Selectable 5V and 3.3V trip point tolerance x Internal power drawn from highest input voltage, 5V or 3.3V x Precision temperature-compensated voltage reference and comparator x Low-cost surface mount SO, compact MicroSO and DIP packages x Wide operating temperature, - 40C to +85C
IMP1834A
2 5VRESET
Block Diagram
IMP1834
5VIN 1
1834_02.eps
7
3.3VRESET
5VTOL
3
5V Tolerance Bias Low TC Reference 40k
+ -
For IMP1834D 350 ms Delay 2 5VRESET 5VRESET (IMP1834D)
PBRST 3.3VIN 3.3VTOL GND
5 8 6 4 3.3V Tolerance Bias
Pushbutton Level Sense and Debounce
For IMP1834D
+ -
350 ms Delay
7
3.3VRESET 3.3VRESET (IMP1834D)
1834_01.eps
(c) 1999 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP183 4/A/D
Pin Configuration
DIP/SO/MicroSO
5VIN 5VRESET* 5VTOL GND 1 2 3 4 IMP1834 IMP1834A IMP1834D 8 7 6 5 3.3VIN 3.3VRESET* 3.3VTOL PBRST
* IMP1834D reset outputs are active HIGH (5VRESET and 3.3VRESET). Outputs are open drain for IMP1834A.
1834_03.eps
Pin Descriptions
Pin Number
1 2 3 4 5 6 7 8
Name
5VIN 5VRESET 5VRESET 5VTOL GND PBRST 3.3VTOL 3.3VRESET 3.3VRESET 3.3VIN 5V power supply input.
Function
5V reset output (Active LOW, IMP1834, IMP1834A. Open drain outputs for IMP1834A). 5V reset output (Active HIGH, IMP1834D). 5V input tolerance select: 10% tolerance for 5VTOL 5VIN and 5% tolerance for 5VTOL = GND. Ground. Debounced manual pushbutton reset input (40k internal pull up). 3.3V input tolerance select: 20% tolerance for 3.3VTOL = 3.3VIN, and 10% tolerance for 3.3VTOL = GND. 3.3V reset output (Active LOW, IMP1834, IMP1834A. Open drain outputs for IMP1834A). 3.3V reset output (Active HIGH, IMP1834D). 3.3V power supply input.
1834_01t.eps
Ordering Information
Part Number
IMP1834 IMP1834EMA IMP1834S IMP1834/D IMP1834A IMP1834AEMA IMP1834AS IMP1834A/D IMP1834D IMP1834DEMA IMP1834DS IMP1834D/D
Package
8-DIP MicroSO 8-SO DICE 8-DIP MicroSO 8-SO DICE 8-DIP MicroSO 8-SO DICE
Operating Temperature Range
- 40C to 85C - 40C to 85C - 40C to 85C 25C - 40C to 85C - 40C to 85C - 40C to 85C 25C - 40C to 85C - 40C to 85C - 40C to 85C 25C
Reset Polarity
LOW LOW LOW LOW LOW LOW LOW LOW HIGH HIGH HIGH HIGH
Output Stage
Push-Pull Push-Pull Push-Pull Push-Pull Open Drain Open Drain Open Drain Open Drain Push-Pull Push-Pull Push-Pull Push-Pull
1834_02t.eps
2
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IMP183 4/A/D
Absolute Maximum Ratings
Voltage on VIN pins . . . . . . . . . . . . . . . . -0.5V to 7V Voltage on 5VRESET . . . . . . . . . . . . . . . -0.5V to (+5VIN +0.5V) (IMP1834, IMP1834D) Voltage on 3.3VRESET . . . . . . . . . . . . . . -0.5V to (+3.3VIN +0.5V) (IMP1834, IMP1834D) Voltage on PBRST and reset outputs . . -0.5V to the greater of 5VIN +0.5V or 3.3VIN +0.5V (IMP1834A) Operating Temperature Range . . . . . . . -40C to 85C Storage Temperature . . . . . . . . . . . . . . . -55C to 125C Soldering Temperature . . . . . . . . . . . . . . 260C for 10 seconds Voltages measured with respect to ground. These are stress ratings only and functional operation is not implied.
Electrical Characteristics
Recommended DC operating condition over the operating temperature range of -40C to +85C. All voltages are referenced to ground.
Parameter
5V Supply Voltage (5VIN) 3.3V Supply Voltage (3.3V) PBRST Input High Level PBRST Input High Level PBRST Input Low Level
Symbol
5VIN 3.3VIN VIH VIH VIL
Conditions
Both 3.3VIN and 5VIN 2.7V Both 3.3VIN and 5VIN 2.7V
Min
1.2 1.2 2 VINMAX - 0.4V - 0.3
Typ
Max
5.5 5.5 VINMAX + 0.3V 0.5
Units
V V V V V
Unless otherwise noted, VIN = 1.2V to 5.5V and specifications are over the operating temperature range of -40C to +85C.
Parameter
Output Voltage Input Leakage Output Current
Symbol
VOH IIL IOH
Conditions
Output = 2.4V. Either 3.3VIN or 5VIN 2.7V. (IMP1834/1834D only) Output = 0.4V. Either 3.3VIN or 5VIN 2.7V. (IMP1834/1834D only) 3.3VIN and 5VIN 5.5V, RESET outputs open. 3.3VIN and 5VIN 3.6V, RESET outputs open. 5VTOL = GND 5VTOL = 5VIN 3.3VTOL = GND 3.3VTOL = 3.3VIN
Min
-1.0
Typ
VIN - 0.1V 350
Max
+1.0
Units
V A A
Output Current
IOL
+10
mA A A V V V V pF ms ms ms s s ns ms
5V Operating Current 3.3V Operating Current 5V Trip Point 5V Trip Point 3.3V Trip Point 3.3V Trip Point Output Capacitance PBRST Manual Reset Minimum Low Time PBRST Stable LOW to Reset Active Reset Active Time VCC Detect Noise Immunity VCC Slew Rate VCC Slew Rate VCC Detect to RESET or RESET
ICC ICC VINTP VINTP VINTP VINTP COUT tPB tPDLY tRST tRPD tF tR tRPU
16 12 4.50 4.25 2.80 2.47 2 4.63 4.38 2.88 2.55
30 25 4.75 4.49 2.97 2.64 10
2 200 VINTP (MAX) to VINTP (MIN) VINTP (MIN) to VINTP (MAX) trise = 5s 300 0 200 350 500 2
350
500
(c) 1999 IMP, Inc.
408-432-9100/www.impweb.com
3
IMP183 4/A/D
Application Information
Operation - Power Monitor
The IMP1834 supervisors simultaneously detect out-of-tolerance power supply conditions on both 3.3V and 5V power supplies. If the voltages at 5VIN or 3.3VIN are outside the tolerance band, the reset for the failing supply voltage becomes active. When the monitored supply returns to an in-tolerance state, the reset remains active for approximately 350ms before returning to the inactive state. On power-up, the reset signals are kept active for approximately 350ms after the power supply voltages have reached the selected tolerance. This allows the power supply and microprocessor to stabilize before the reset is removed. All supply current for the IMP1834 devices is drawn from the input (5VIN or 3.3VIN) with the highest voltage level. The outputs draw current from their input supplies 5VIN and 3.3VIN.
tR VINTP (Max) VINTP (Min) VINTP
Reset Signal Polarity and Output Stage Structure
The IMP1834 and IMP1834A supervisors have active LOW reset signals. The IMP1834D reset outputs are active HIGH. The IMP1834 and IMP1834D have CMOS push-pull output stages. The IMP1834A has open drain reset outputs.
IMP Part
IMP1834 IMP1834EMA IMP1834S IMP1834A IMP1834AEMA IMP1834AS IMP1834D IMP1834DEMA IMP1834DS
RESET Polarity
LOW LOW LOW LOW LOW LOW HIGH HIGH HIGH
Output Stage Configuration
Push-Pull Push-Pull Push-Pull Open Drain Open Drain Open Drain Push-Pull Push-Pull Push-Pull
Trip Point Tolerance Selection
The 3.3VTOL and 5VTOL inputs allow independent selection of the reset trip points. If 5VTOL is connected to the 5V supply input, a 10% tolerance is selected. If 5VTOL is grounded, a 5% tolerance is selected.
RESET VOH
VIN tRPU
If 3.3VTOL is connected to the 3.3V supply input, a 20% tolerance is selected. If 3.3VTOL is grounded, a 10% tolerance is selected. See Table 1. The 3.3VTOL and 5VTOL tolerance select inputs should be tied to ground or to the respective input supply voltage pin, 3.3VIN or 5VIN.
VOL
RESET (IMP1834D Only)
1834_10.eps
Figure 1. Timing Diagram: Power Up
VIN
tF VINTP (Max) VINTP VINTP (Min)
> tRPD RESET
VOH VOL RESET (IMP1834D Only)
RESET Slews with VCC
1834_09.eps
Figure 2. Timing Diagram: Power Down
4
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IMP183 4/A/D
Application Information
Table 1. Threshold Selection
3.3V Input Tolerance Select
5VTOL = 5VIN 5VTOL = GND 3.3VTOL = 3.3VIN 3.3VTOL = GND
5V Input MAX
-- -- 2.64 2.97
3.3V Tolerance
-- -- 20% 10%
TRIP Point (V) MIN
-- -- 2.47 2.80
Nominal
-- -- 2.55 2.88
5V Tolerance
10% 5% -- --
TRIP Point (V) MIN
4.25 4.5 -- --
Nominal
4.38 4.63 -- --
MAX
4.49 4.75 -- --
1834_03t.eps
Manual Reset Operation
Pushbutton switch input, PBRST, allows the user to override the internal trip point detection circuits and issue reset signals. The pushbutton input is debounced and is pulled HIGH through a 40k, internal pull-up resistor. When at least one of the reset outputs is not asserted, a pushbutton initiated reset signal can be issued by holding PBRST LOW for at least 2ms. When PBRST is held LOW, both resets become active and remain active for approximately 350ms after PBRST returns HIGH. See Figure 3 and Figure 4.
5V IMP1834 1 2 3 4 5VIN 3.3VIN 8 7 6 5
3.3V tPB tPDLY VIL tRST RESET VOH VOL
1834_05.eps
PBRST
VIH
5VRESET 3.3VRESET 5VTOL GND 3.3VTOL PBRST
1834_04.eps
RESET (IMP1834D)
Figure 3. Pushbutton Reset
Figure 4. Timing Diagram: Pushbutton Reset
(c) 1999 IMP, Inc.
408-432-9100/www.impweb.com
5
IMP183 4/A/D
Application Information
Reset Output Signal
Reset output signals are valid as long as either voltage at 5VIN or 3.3VIN is above 1.2V. In addition, the IMP1834 has push-pull outputs that can remain valid below a 1.2V input level. To sink current below 1.2V, a resistor should be connected from the reset output to ground. This resistor guarantees a valid reset signal down to 0V. A 100k value is suggested. The IMP1834A open drain reset outputs require pull-up resistors and must be low enough in value to pull the output into a HIGH state. Resistor value is not critical in most applications and a value of 10k is suggested. See Figure 5 and Figure 6. The IMP1834A open drain reset outputs can be connected to the same potential through a single pull up resistor. In this configuration a failure on either supply will generate an active LOW reset. If the outputs are pulled-up to different voltages, the reset outputs (pin 2 and pin 7) should not be connected. See Figure 7.
5V IMP1834A 10k 1 2 3 4 5VIN 3.3VIN 8 7 6 5 10k 3.3V
5VRESET 3.3VRESET 5VTOL GND 3.3VTOL PBRST
1834_07.eps
Figure 6. IMP1834A Open Drain Output Pull-Up Resistor
5V 3.3V IMP1834A 1 2 5VIN 3.3VIN 8 7 6 5 10k 5V or 3.3V
RESET
P Input 100k
1834_06.eps
5VRESET 3.3VRESET 5VTOL GND 3.3VTOL PBRST
3
Figure 5. IMP1834 RESET Valid to 0V
4
1834_08.eps
Figure 7. IMP1834A Wired "OR" Connection
6
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(c) 1999 IMP, Inc.
IMP183 4/A/D
Package Dimensions Absolute Maximum Ratings
MicroSO (8-Pin)
a
Inches Min
A A1 A2 b C D e E E1 L a A A1 B C e E H L D
Millimeters Max Min Max MicroSO (8-Pin)*
E1 E
L D A2 A e b A1
0.10mm 0.004in
C
MicroSO (8-Pin).eps
----- 0.0433 0.0020 0.0059 0.0295 0.0374 0.0098 0.0157 0.0051 0.0091 0.1142 0.1220 0.0256 BSC 0.193 BSC 0.1142 0.1220 0.0157 0.0276 0 6
---- 1.10 0.050 0.15 0.75 0.95 0.25 0.40 0.13 0.23 2.90 3.10 0.65 BSC 4.90 BSC 2.90 3.10 0.40 0.70 0 6 1.35 0.10 0.33 0.19 1.27 3.80 5.80 0.40 4.80 ---- 0.38 2.92 0.36 1.14 0.80 9.02 0.13 7.62 6.10 2.54 7.62 ----- 2.92 10.92 3.81
1834_t04.at3
D
+
SO (8-Pin)**
0.053 0.004 0.013 0.007 0.050 0.150 0.228 0.016 0.189 0.157 0.244 0.050 0.197 0.069 0.010 0.020 0.010 1.75 0.25 0.51 0.25 4.00 6.20 1.27 2.00 5.33 ----- 4.95 0.56 1.78 1.14 10.16 ----- 8.26 7.11
SO (8-Pin)
0- 8
L
E
H
Plastic DIP (8-Pin)***
A ----- 0.210 A1 0.015 ----- A2 0.115 0.195 b 0.014 0.022 b2 0.045 0.070 b3 0.030 0.045 D 0.355 0.400 D1 0.005 ----- E 0.300 0.325 E1 0.240 0.280 e 0.100 ----- eA 0.300 ----- eB ----- 0.430 eC ----- 0.060 L 0.115 0.150 *** JEDEC Drawing MO-187AA *** JEDEC Drawing MS-112AA *** JEDEC Drawing MS-001BA
C D A
e B A1
SO (8-Pin).eps
Plastic DIP (8-Pin)
D1
E D A A2 E1
L A1 e b b2
0-15 C eA eB
Plastic DIP (8-Pin)a.eps
(c) 1999 IMP, Inc.
408-432-9100/www.impweb.com
7
IMP183 4/A/D
IMP, Inc. Corporate Headquarters 2830 N. First Street San Jose, CA 95134-2071 Tel: 408-432-9100 Tel: 800-438-3722 Fax: 408-434-0335 Fax-on-Demand: 1-800-249-1614 (USA) Fax-on-Demand: 1-303-575-6156 (International) e-mail: info@impinc.com http://www.impweb.com
The IMP logo is a registered trademark of IMP, Inc. All other company and product names are trademarks of their respective owners.
(c) 1999 IMP, Inc. Printed in USA Publication #: 1009 Revision: A Issue Date: 07/02/99 Type: Preliminary

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