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Voltage Supervisor. MIC1232 Datasheet |
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MIC1232
5V Voltage Supervisor with Manual Reset,
Watchdog Timer and Dual Reset Outputs
General Description
The MIC1232 is a low-current microprocessor supervisor
for monitoring 5V systems. The device features logic
selectable (TOL) reset thresholds of 5% or 10% of 5V; a
pushbutton reset input (/PBRST); a watchdog timer with
three-state selectable (TD) timeout periods of 150ms,
600ms, or 1.2s; a fixed reset timeout period of 250ms
(min); and active-low open-drain reset (/RST) and active-
high push-pull reset (RST) outputs. The /RST output
maintains a valid reset condition for VCC as low as 1.4V.
The MIC1232 asserts a reset condition if the supply
voltage drops below the reset threshold, the pushbutton
reset is asserted low, or the watchdog timer does not see
a high-to-low transition on the watchdog timer input within
the watchdog timer period. A reset condition is held for the
reset timeout period of 250ms (min) after the pushbutton
input is released or after the supply voltage increases
above the reset threshold voltage.
The MIC1232 is a drop-in replacement for the DS1232,
MAX1232, and TC1232. It consumes a low 18µA (typ) of
supply current, 40µA (max). This is one-tenth the max
current of the DS1232, and one-quarter the max current of
the MAX1232 and TC1232. It operates over the –40C to
+85C temperature range and is available in the Pb-Free
8-pin SOIC and PDIP packages.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
• Low-current version of
DS1232/MAX1232/TC1232/CAT1232
• Low current: 18µA (typ), 40µA (max)
• Selectable threshold (TOL): 5% or 10% of 5V
• Selectable watchdog timer (TD): 150ms, 600ms, 1.2s
• Power OK/Reset time delay: 250ms (min)
• Debounced pushbutton reset input (/PBRST)
• Dual complementary reset outputs
– Active-low, open-drain reset output
– Active-high, push-pull reset output
• Available in Pb-Free 8-pin SOIC and PDIP packages
• –40°C to +85°C temperature range
• Pin-for-Pin compatible with MIC1832/DS1832/CAT1832
Applications
• Automotive systems
• Intelligent systems
• Critical microprocessor power monitoring
• Battery powered computers
• Controllers
_________________________________________________________________________________________________________________________
Typical Application
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2013
M9999-020413
|
Micrel, Inc.
Ordering Information
Part Number
MIC1232NY
MIC1232MY
Temperature Range
–40° to +85°C
–40° to +85°C
Package
8-Pin PDIP
8-Pin SOIC
Pin Configuration
Lead Finish
Pb-Free
Pb-Free
MIC1232
8-Pin PDIP
8-Pin SOIC
Pin Description
Pin Number Pin Name
1 /PBRST
2 TD
3 TOL
4 GND
5 RST
6 /RST
7 /ST
8 VCC
Pin Function
Pushbutton Reset input: This input is debounced and can be driven with external logic signals or by
using a mechanical pushbutton to actively force a reset. All pulses less than 1ms in duration on the
/PBRST pin are ignored; any pulse with a duration of 20ms or greater is guaranteed to cause a
reset.
Time Delay input: This input selects the timebase used by the watchdog timer. When TD = 0V, the
watchdog timeout period is set to a normal value of 150ms. When TD = open, the watchdog timeout
period is set to a nominal value of 600ms. When TD = VCC, the watchdog period is 1.2s nominally.
Tolerance Select input: This input selects whether 5% or 10% of VCC is used as the reset threshold
voltage. When TOL = 0V, the 5% tolerance level is selected and when TOL = VCC, a 10% tolerance
level is selected.
IC ground pin, 0V reference.
RST is asserted high if either VCC goes below the reset threshold, the watchdog times out, or
/PBRST is pulled low for a minimum of 20ms. RST remains asserted for one reset timeout period
after VCC exceeds the reset threshold, after the watch times out, or after /PBRST goes high.
/RST is asserted low if either VCC goes below the reset threshold, the watchdog times out, or
/PBRST is pulled low for a minimum of 20ms. /RST remains asserted for one reset timeout period
after VCC exceeds the reset threshold, after the watch times out, or after /PBRST goes high. Open-
drain output.
Input to watchdog timer. If /ST does not see a transition from high to low within the watchdog
timeout period, RST and /RST will be asserted.
Primary supply input, +5V.
February 2013
2 M9999-020413
|
Micrel, Inc.
MIC1232
Absolute Maximum Ratings(1)
Terminal Voltage
VCC ......................................................... −0.3V to +6.0V
All other inputs ............................. −0.3V to (VCC + 0.3V)
Input Current
VCC ......................................................................250mA
GND, all other inputs ............................................25mA
Lead Temperature (soldering, 10sec.) ....................... 300°C
Storage Temperature (Ts)........................... −65°C to 150°C
ESD Rating(3).......................................................see Note 3
Operating Ratings(2)
Operating Temperature Range
MIC1232M/N......................................... –40°C to +85°C
Electrical Characteristics
VCC = 4.5 V to 5.5V; TA = Operating Temperature Range; bold values indicate –40°C≤ TA ≤ +85°C, unless noted.
Parameter
Condition
Min Typ Max
Supply Voltage Range
Supply Current
/ST and /PBRST Input Levels
VCC
ICC(4)
VIH(5)
4.5
18
2.0
VIL −0.3
Input Leakage
IIL
Output Source Current, RST
VOH = 2.4V
1.0 10
Output Sink Current, /RST. RST
VOL = 0.4V
2.0 10
VCC 5% Trip Point (Reset Threshold Voltage)
TOL = GND
4.5 4.62
VCC 10% Trip Point (Reset Threshold Voltage)
Input Capacitance, /ST, TOL
Output Capacitance, /RST, RST
TOL = VCC
CIN(6)
COUT(6)
4.25 4.37
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. ICC is measured with outputs open and inputs within 0.5V of supply rails.
5. /PBRST has an internal pull-up resistor to VCC (typ. 40kΩ).
6. Guaranteed by design.
5.5
40
VCC + 0.3
0.8
±1
4.74
4.49
5
7
Units
V
µA
V
V
µA
mA
mA
V
V
pF
pF
February 2013
3 M9999-020413
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