Micrel MIC2772 Dual voltage supervisor Datasheet

MIC2772
Dual Voltage Supervisor
General Description
Features
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.
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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
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Servers
Embedded Controllers
Telecommunications Systems
Power Supply Sequencing
Hot-swapping
Power supplies
____________________________________________________________________________________________________
Typical Application
VCC1
10k
MR1
VCC1
RESET1
GND1
VCC
RESET
GND
µP
VCC
RESET
GND
µP
VCC2
10k
MR2
VCC2
RESET2
GND2
MIC2772 Typical Application Circuit
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MIC2772
Ordering Information
Part Number
Standard
MIC2772-L3L3BML(1)
MIC2772-M3M3BML(1)
MIC2772-T3T3BML(1)
MIC2772-S3S3BML(1)
Top Mark
Standard Pb-Free
Pb-Free
MIC2772-L2L3YML(2)
MIC2772-M2M3YML (2)
MIC2772-L3L3YML(1)
MIC2772-M3M3YML(1)
MIC2772-T3T3YML(1)
MIC2772-S3S3YML(1)
MIC2772-T2T3YML(2)
MIC2772-S2S3YML(2)
MIC2772-L3T3YML(2)
MIC2772-M3S3YML(2)
UP0
UP1
UP2
UP3
UP4
UP5
UP6
UP7
UP8
UP9
UP2
UP3
UP4
UP5
Supervisor 1
tRESET
VTH (V)
(ms)
4.63
20
4.38
20
4.63
140
4.38
140
3.08
140
2.93
140
3.08
20
2.93
20
4.63
140
4.38
140
Supervisor 2
tRESET
VTH (V)
(ms)
4.63
140
4.38
140
4.63
140
4.38
140
3.08
140
2.93
140
3.08
140
2.93
140
3.08
140
2.93
140
Note:
1.
Available now.
2.
Contact factory.
Pin Configuration
MR1
1
8
VCC1
GND1
2
7
RESET1
MR2
3
6
VCC2
GND2
4
5
RESET2
8-lead 2mm X 2mm MLF(ML)
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MIC2772
Pin Description
Pin Number
April 2005
Pin Name
1
/MR1
2
GND1
3
/MR2
4
GND2
5
/RESET2
6
VCC2
7
/RESET1
8
VCC1
Pin Function
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 tRESET1 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.
Ground return for supervisor 1.
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 tRESET2 later. /MR2
may be driven by a CMOS or TTL logic signal or a mechanical switch. Debouncing is performed internally. /MR2 has an internal pull-up to VCC2; leave
open if unused.
Ground return for supervisor 2.
Digital Output; open-drain; supervisor 2. Asserted low whenever VCC2 falls
below the threshold voltage. It remains asserted for no less than tRESET2 and is
de-asserted after VCC2 returns above the threshold.
Analog Input. Power supply input for supervisor 2.
Digital Output; open-drain; supervisor 1. Asserted low whenever VCC1 falls
below the threshold voltage. It remains asserted for no less than tRESET1 and is
de-asserted after VCC1 returns above the threshold.
Analog Input. Power supply input for supervisor 1.
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MIC2772
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage, VCC ...............................-0.3V to 6.0V
Input Voltage, /MR ....................... -0.3V to VCC + 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
Supply Voltage...........................................1V to 5.5V
Input Voltage (/MR )..................................... 0 to 5.5V
Input Voltage (/RESET ) ............................ 0 to +5.5V
Operating Temperature Range (TA).... -40°C to +85°C
Lead Temperature – Soldering, 10s .................300°C
Package Thermal Resistance (θJA)................ 93°C/W
Electrical Characteristics
For typical values, TA = 25°C, 2.5V ≤ VCCn ≤ 5.5V; values in bold are for 2.5V ≤ VCCn ≤ 5.5V, TMIN ≤ TA ≤ TMAX,
unless otherwise noted.
Symbol
Parameter
Condition
Min
Typ
Max
Units
/MR1 = /MR2 = /RESET1 = /RESET2 =
open, VCC1 = VCC2 = 5.5V
10
30
µA
/MR1 = /MR2 = /RESET1 = /RESET2 =
open, VCC1 = VCC2 = 3.6V
10
20
µA
/MR1 = /MR2 = /RESET1 = /RESET2 =
open, VCCn = 0V, VCCm = 5.5V
5
15
µA
/MR1 = /MR2 = /RESET1 = /RESET2 =
open, VCCn = 0V, VCCm = 3.6V
5
10
µA
Power Supply
IDD
Supply Current
/RESETn OUTPUTS
VTHn
tRESET
Reset-voltage threshold
Reset Pulse Width
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
T voltage code
3.00
3.08
3.15
V
timeout code = 2
20
44
ms
VOL
ILEAK
/RESET Output Voltage Low
Output leakage
timeout code = 3
140
320
timeout code = 4
1100
2500
VCCn ≥ 4.25V, ISINK = 3.2mA
0.4
V
VCCn ≥ 2.5V, ISINK = 1.2mA
0.3
V
VCCn ≥ 1V, ISINK = 50µA
0.3
V
/RESET not asserted
±1
µA
/MRn INPUTS
VIH
VIL
Input Voltage, High
Input Voltage, Low
April 2005
VTHn > 4.0V
2.3
V
VTHn < 4.0V
0.7*V
CC
V
VTHn > 4.0V
0.8
V
VTHn < 4.0V
0.25*
VCC
V
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MIC2772
Electrical Characteristics cont.
Symbol
Parameter
Condition
tPROP
/MR to /RESET Propagation
Delay
/MRn < VIL → /RESETn < VIL
tMIN
Minimum Input Pulse Width
Reset Occurs
tREJECT
Widest Pulse Ignored
No Reset Occurs
RPU
Min
Typ
Max
0.5
µs
10
10
Pull-up Resistance
Units
µs
100
ns
20
kΩ
30
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
VCCn
VTH
/MRn
/RESETn
tRST
tRST
MIC2772 Timing Diagram
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MIC2772
Functional Block Diagram
VCC
MR1 (1)
RESET
GENERATOR
RESET1 (7)
RESET
GENERATOR
RESET2 (5)
+
VCC1 (8)
Reset
Threshold (V)
GND1 (2)
VCC
MR2 (3)
+
VCC2 (6)
Reset
Threshold (V)
GND2 (4)
MIC2772 Block Diagram
Application Information
Reset Output, /RESET
The /RESET pin is active low (open drain) pin. The
/RESET pin is asserted whenever VCC falls below
the reset threshold voltage or if /MR (manual reset)
is forced low. The /RESET pin remains asserted for
the duration of the threshold timeout period after
VCC has risen above the reset threshold and/or /MR
has returned high. The reset function ensures the
microprocessor is properly reset and power up in a
known condition after a power failure. /RESET will
remain valid with VCC as low as 1.0V.
The /RESET output is a simple open-drain Nchannel MOSFET structure. A pull-up resistor must
be used to pull this output to some voltage. For
most applications, this voltage will be the same
power supply that supplies VCC to MIC2772. It is
possible however to tie this resistor to some other
voltage. This will allow the MIC2772 to monitor one
voltage while level-shifting the /RESET output to
some other voltage. The pull-up voltage must be
limited to 6.0V or less (absolute maximum) to avoid
damage to the MIC2772. The resistor must be small
enough to supply current to the inputs and leakage
paths that are driven by the /RESET output.
April 2005
Manual Reset Input, /MR
The ability to initiate a reset via external logic or a
manual switch is provided in addition to the
MIC2772’s automatic supervisory functions. Driving
the /MR input to a logic low causes an immediate
and unconditional reset to occur. Assuming VCC is
within tolerance when /MR is released (returns high),
the /RESET output will be de-asserted no less than
tRESET later. /MR may be driven by a CMOS or TTL
logic signal, or a mechanical switch. Typically, a
momentary push-button switch is connected such
that /MR is shorted to ground when the switch
contacts close. Switch de-bouncing is performed
internally; the switch may be connected directly
between /MR and GND. /MR has an internal 20kΩ
pull-up resistor (typical) to VCC and may be left
open if unused.
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MIC2772
Motorola 68HC11 family is one example. Because
the MIC2772’s output is active-low, open-drain, it
can be connected directly to the processor’s reset
pin with only the pull-up resistor normally required.
MAX. TRANSIENT DURATION (µs)
Transients on VCC
The MIC2772 is inherently immune to very short
“glitches” on VCC.
In the case of very brief
transients, VCC may drop below the reset-voltage
threshold without triggering a reset. As shown in the
graph, the MIC2772 is relatively immune to
transients with typical duration of 25us. The lines on
the graph represent the typical allowable transient
duration for a given amount of threshold overdrive
that will not generate a reset. The data was taken by
adding negative-going square-wave pulse to a DC
input voltage set at 0.5V above actual measured
threshold for the part being characterized. Figure 1
shows the graph for the MIC2772[UP3] and Figure 2
shows the graph for the MIC2772[UP5]
35
MIC2772 Replaces Single Supervisor
The table below lists common single voltage
supervisors that can be considered for replacement
by MIC2772.
Typical Transient
Response
P/N Suffix
Supervisor #1
Supervisor #2
L2L3
MIC6315-46D2
MIC1810-5,
MIC6315-46D3,
MIC809L, MIC811L
M2M3
MIC6315-44D2
MIC1810-10,
MIC6315-44D3,
MIC809M,
MIC811M
L3L3
MIC1810-5,
MIC6315-46D3,
MIC809L, MIC811L
MIC1810-5,
MIC6315-46D3,
MIC809L, MIC811L
M3M3
MIC1810-10,
MIC6315-44D3,
MIC809M,
MIC811M
MIC1810-10,
MIC6315-44D3,
MIC809M,
MIC811M
T3T3
MIC6315-31D3,
MIC809T, MIC811T
MIC6315-31D3,
MIC809T, MIC811T
S3S3
MIC1815-10,
MIC6315-29D3,
MIC809S, MIC811S
MIC1815-10,
MIC6315-29D3,
MIC809S, MIC811S
T2T3
MIC6315-31D2
MIC6315-31D3,
MIC809T, MIC811T
S2S3
MIC6315-29D2
MIC1815-10,
MIC6315-29D3,
MIC809S, MIC811S
L3T3
MIC1810-5,
MIC6315-46D3,
MIC809L, MIC811L
MIC6315-31D3,
MIC809T, MIC811T
M3S3
MIC1810-10,
MIC6315-44D3,
MIC809M,
MIC811M
MIC1815-10,
MIC6315-29D3,
MIC809S, MIC811S
30
25
20
15
10
5
0
VTH = 4.393V
0
200 400 600 800 1000
RESET COMP. OVERDRIVE VTH - VCC (mV)
MAX. TRANSIENT DURATION (µs)
Figure 1
40
Typical Transient
Response
35
30
25
20
15
10
5
VTH = 2.933V
0
0
200 400 600 800 1000
RESET COMP. OVERDRIVE VTH - VCC (mV)
Figure 2
Interfacing to Processors with Bi-directional
Reset Pins
Some microprocessors have reset signal pins that
are bi-directional, rather than input only. The
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MIC2772
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MIC2772
Package Information
8-Pin 2mm X 2mm MLF (ML)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for
its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a
product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for
surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant
injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk
and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Incorporated.
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