MIC2772
Dual Voltage Supervisor
General Description
The MIC2772 is a dual power supply supervisor that
provides under-voltage monitoring and power-on
reset generation. It may replace two discrete
voltage supervisors such as MIC1810, MIC1815,
MIC809, MIC811, MIC6315, etc. The two voltage
supervisors are completely independent. Each
functional block features an under-voltage detector,
a delay-generator, and a de-bounced manual reset
input.
A wide choice of voltage thresholds is available.
The reset output is asserted at power-on and any
time the input voltage drops below the reference
voltage. It remains asserted for the chosen timeout
period after the input rises back above the threshold.
Reset timeouts of 20, 140, and 1100ms (minimum)
are available.
A reset can be generated at any time by asserting
the manual reset input, /MR. This input is internally
de-bounced, and the reset output will remain active
for the timeout period after the release of /MR. The
/MR input can also be used to daisy-chain one or
more of the MIC2772's supervisors onto existing
power monitoring circuitry or other supervisors.
The tiny 2x2mm MLF package has a footprint
smaller than that of a single SOT23 voltage
supervisor.
Data sheets and support documentation can be
found on Micrel's web site at
www.micrel.com
.
Features
Two independent voltage supervisors
Directly replaces discrete supervisors
Generates power-on reset pulses
De-bounced manual reset Inputs
Choice of voltage thresholds
20, 140, or 1100ms reset timeouts
Reset output may be pulled above VCC
Rejects brief input transients
Ultra-small 2x2mm MLF package
Applications
Servers
Embedded Controllers
Telecommunications Systems
Power Supply Sequencing
Hot-swapping
Power supplies
____________________________________________________________________________________________________
Typical Application
MR1
MR2
GND2
RESET2
VCC2
VCC2
10k
10k
RESET1
VCC1
VCC1
GND1
RESET
VCC
GND
GND
RESET
VCC
P
P
MIC2772 Typical Application Circuit
April 2005
M9999-042005
(408) 955-1690
Micrel
MIC2772
Ordering Information
Part Number
Top Mark
Supervisor 1
Supervisor 2
Standard Pb-Free
Standard
Pb-Free
V
TH
(V)
t
RESET
(ms)
V
TH
(V)
t
RESET
(ms)
MIC2772-L2L3YML
(2)
UP0
4.63
20
4.63
140
MIC2772-M2M3YML
(2)
UP1
4.38
20
4.38
140
MIC2772-L3L3BML
(1)
MIC2772-L3L3YML
(1)
UP2 UP2 4.63 140
4.63
140
MIC2772-M3M3BML
(1)
MIC2772-M3M3YML
(1)
UP3 UP3 4.38 140
4.38
140
MIC2772-T3T3BML
(1)
MIC2772-T3T3YML
(1)
UP4 UP4 3.08 140
3.08
140
MIC2772-S3S3BML
(1)
MIC2772-S3S3YML
(1)
UP5 UP5 2.93 140
2.93
140
MIC2772-T2T3YML
(2)
UP6
3.08
20
3.08
140
MIC2772-S2S3YML
(2)
UP7
2.93
20
2.93
140
MIC2772-L3T3YML
(2)
UP8
4.63
140
3.08
140
MIC2772-M3S3YML
(2)
UP9
4.38
140
2.93
140
Note
:
1. Available
now.
2. Contact
factory.
Pin Configuration
1
MR1
GND1
MR2
GND2
8
VCC1
RESET1
VCC2
RESET2
7
6
5
2
3
4
8-lead 2mm X 2mm MLF(ML)
April 2005
2
M9999-042605
(408) 955-1690
Micrel
MIC2772
Pin Description
Pin Number
Pin Name
Pin Function
1
/MR1
Digital Input; supervisor 1. Driving this pin low initiates an immediate and
unconditional reset. If VCC1 is above the threshold when /MR1 is released
(returns high), RESET1 will be de-asserted no less than t
RESET1
later. /MR1 may
be driven by a CMOS or TTL logic signal or a mechanical switch. De-bouncing
is performed internally. /MR1 has an internal pull-up to VCC1; leave open if
unused.
2
GND1
Ground return for supervisor 1.
3
/MR2
Digital Input; supervisor 2. Driving this pin low initiates an immediate and
unconditional reset. If VCC2 is above the threshold when /MR2 is released
(returns high), the /RESET2 will be de-asserted no less than t
RESET2
later. /MR2
may be driven by a CMOS or TTL logic signal or a mechanical switch. De-
bouncing is performed internally. /MR2 has an internal pull-up to VCC2; leave
open if unused.
4
GND2
Ground return for supervisor 2.
5
/RESET2
Digital Output; open-drain; supervisor 2. Asserted low whenever VCC2 falls
below the threshold voltage. It remains asserted for no less than t
RESET2
and is
de-asserted after VCC2 returns above the threshold.
6
VCC2
Analog Input. Power supply input for supervisor 2.
7
/RESET1
Digital Output; open-drain; supervisor 1. Asserted low whenever VCC1 falls
below the threshold voltage. It remains asserted for no less than t
RESET1
and is
de-asserted after VCC1 returns above the threshold.
8
VCC1
Analog Input. Power supply input for supervisor 1.
April 2005
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M9999-042605
(408) 955-1690
Micrel
MIC2772
Absolute Maximum Ratings
(1)
Supply Voltage, V
CC
...............................-0.3V to 6.0V
Input Voltage, /MR ....................... -0.3V to V
CC
+ 0.3V
Input Voltage, /RESET ..........................-0.3V to 6.0V
Input Current (VCC, /MR) ................................. 20mA
Output Current (/RESET) ................................ 20mA
Storage Temperature....................... -65
C to +150
C
ESD Rating (Note 3) .............................................3kV
Operating Ratings
(2)
Supply Voltage...........................................1V to 5.5V
Input Voltage (/MR )..................................... 0 to 5.5V
Input Voltage (/RESET ) ............................ 0 to +5.5V
Operating Temperature Range (T
A
).... -40
C to +85
C
Lead Temperature Soldering, 10s .................300C
Package Thermal Resistance (
JA
)................ 93C/W
Electrical Characteristics
For typical values, T
A
= 25
C, 2.5V
VCCn
5.5V; values in bold are for 2.5V
VCCn
5.5V, T
MIN
T
A
T
MAX
,
unless otherwise noted.
Symbol Parameter
Condition
Min Typ Max Units
Power Supply
I
DD
Supply Current
/MR1 = /MR2 = /RESET1 = /RESET2 =
open, VCC1
= VCC2 = 5.5V
10
30
A
/MR1 = /MR2 = /RESET1 = /RESET2 =
open, VCC1
= VCC2 = 3.6V
10
20
A
/MR1 = /MR2 = /RESET1 = /RESET2 =
open, VCCn = 0V, VCCm = 5.5V
5
15
A
/MR1 = /MR2 = /RESET1 = /RESET2 =
open, VCCn = 0V, VCCm = 3.6V
5
10
A
/RESETn OUTPUTS
L voltage code
4.5
4.63
4.75
V
M voltage code
4.25
4.38
4.50
V
S voltage code
2.85
2.93
3.00
V
V
THn
Reset-voltage threshold
T voltage code
3.00
3.08
3.15
V
timeout code = 2
20
44
ms
timeout code = 3
140
320
t
RESET
Reset Pulse Width
timeout code = 4
1100
2500
V
CCn
4.25V, I
SINK
= 3.2mA
0.4
V
V
CCn
2.5V, I
SINK
= 1.2mA
0.3
V
V
OL
/RESET Output Voltage Low
V
CCn
1V, I
SINK
= 50
A
0.3
V
I
LEAK
Output leakage
/RESET not asserted
1
A
/MRn INPUTS
V
IH
Input Voltage, High
V
THn
> 4.0V
2.3
V
V
THn
< 4.0V
0.7*V
CC
V
V
IL
Input Voltage, Low
V
THn
> 4.0V
0.8
V
V
THn
< 4.0V
0.25*
VCC
V
April 2005
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M9999-042605
(408) 955-1690
Micrel
MIC2772
Electrical Characteristics cont.
Symbol Parameter
Condition
Min Typ Max Units
t
PROP
/MR to /RESET Propagation
Delay
/MRn < V
IL
/RESETn < V
IL
0.5 s
t
MIN
Minimum Input Pulse Width
Reset Occurs
10
s
t
REJECT
Widest Pulse Ignored
No Reset Occurs
100
ns
R
PU
Pull-up Resistance
10
20
30
k
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.
Timing Diagram
V
CCn
/MR
n
/RESET
n
t
RST
t
RST
V
TH
MIC2772 Timing Diagram
April 2005
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