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Datasheet Reliability Report Package Information Order Sample  
Key Specifications
Part Number Description Status Reset Out treset (min) Watchdog Feature Watchdog Timeout Manual Reset Power Fail Comparator Reset Thresh. Accur. (@ +25°C) (%) Icc (max) (µA) RoHS Available Oper. Temp. (°C) Pin/Package EV Kit Available?
UM821xxE μP Reset Circuits with Long Manual Reset Setup Period ACTIVE Push-pull, active LOW 140ms No Yes No 2.5 5 Yes -40 to 85 4/SOT143 Y
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Product Description
 
The UM807/821/822 are low-power microprocessor (μP) supervisory circuits used to monitor power supplies in μP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with 5V-powered or 3V-powered circuits. The UM807/821/822 also provide a debounced manual reset input with long setup period.
On all devices, the reset output asserts when the VCC supply voltage drops below its specified threshold. The reset output remains asserted for the reset timeout period (240ms typ) after VCC rises above the reset threshold. The reset output is one-shot pulse asserted for the reset timeout period (140ms min) when manual reset input is held low for a fixed setup timeout period. These devices ignore manual reset transitions of less than the fixed setup timeout period.
The UM807 has an active-low RESET(_______________) with open-drain output, the UM821 has an active-low RESET(_______________) with push-pull output, and the UM822 has an active-high RESET with push-pull output. These devices, offered in small SOT143 package, are fully guaranteed over the extended temperature range (-40°C to +85°C).
 
Features
 
- No External Components
- VCC Transient Immunity
- Correct Logic Output Guaranteed to VCC=1.0V
- Precision VCC Monitoring of 3.0V, 3.3V and 5.0V Supplies
- 2μA Supply Current
- 140ms Minimum Power-On Reset Pulse Width
- Available in 3 Manual Reset Setup Periods (tMR):
  A: 10.08s
  B: 6.72s
  C: 1.68s
- Available in 3 Output Configurations:
  Open-Drain Active-Low RESET(_______________) Output(UM807);
  Push-Pull Active-Low RESET(_______________) Output(UM821)
  Push-Pull Active-High RESET Output(UM822)
- 4-Pin SOT143 Package
- Wide Operation Temperature: -40°C to +85°C
 
Typical Application Circuit

 
 
Applications
 
- Set-Top Boxes
- Consumer Electronics
- DVD Players
- Cable/DSL Modems
- MP3 Players
- Industrial Equipments
- Automotive
- Medical Devices
 
Pin Configurations  

                
( ) are for UM822
 
Ordering Information
 
UM8 XX Z T P
XX: Output Type
=07   Open-Drain Active Low
=21   Push-Pull Active Low
=22   Push-Pull Active High
Z: Reset Threshold (V)
=L     4.63
=M    4.38
=J     4.00
=T     3.08
=S     2.93
=R     2.63
=Z     2.32
T: Manual Reset Setup Period (s)
=A     10.08
=B     6.72
=C     1.68
P: Package Type
=E     SOT143
 
Selection Table
 
Part Number
RESET Threshold (V)
Timeout Period (ms)
Manual Reset Setup Period (s)
Output Type
Marking Code
Package Type
Shipping Qty
UM821LAE
4.63
240
10.08
Push-Pull, Active Low
1LA
SOT143
3000pcs/7Inch
Tape & Reel
UM821MAE
4.38
240
Push-Pull, Active Low
1MA
UM821JAE
4.00
240
Push-Pull, Active Low
1JA
UM821TAE
3.08
240
Push-Pull, Active Low
1TA
UM821SAE
2.93
240
Push-Pull, Active Low
1SA
UM821RAE
2.63
240
Push-Pull, Active Low
1RA
UM821ZAE
2.32
240
Push-Pull, Active Low
1ZA
UM821LBE
4.63
240
6.72
Push-Pull, Active Low
1LB
UM821MBE
4.38
240
Push-Pull, Active Low
1MB
UM821JBE
4.00
240
Push-Pull, Active Low
1JB
UM821TBE
3.08
240
Push-Pull, Active Low
1TB
UM821SBE
2.93
240
Push-Pull, Active Low
1SB
UM821RBE
2.63
240
Push-Pull, Active Low
1RB
UM821ZBE
2.32
240
Push-Pull, Active Low
1ZB
UM821LCE
4.63
240
1.68
Push-Pull, Active Low
1LC
UM821MCE
4.38
240
Push-Pull, Active Low
1MC
UM821JCE
4.00
240
Push-Pull, Active Low
1JC
UM821TCE
3.08
240
Push-Pull, Active Low
1TC
UM821SCE
2.93
240
Push-Pull, Active Low
1SC
UM821RCE
2.63
240
Push-Pull, Active Low
1RC
UM821ZCE
2.32
240
Push-Pull, Active Low
1ZC
 
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