Micrel MIC2775-31YM5 Micro-power voltage supervisor Datasheet

MIC2775
Micro-Power Voltage Supervisor
IttyBitty®
General Description
Features
The MIC2775 is a power supply supervisor that provides
undervoltage monitoring, manual reset capability, and
power-on reset generation in a compact 5-pin SOT
package. Features include an undervoltage detector, a
delay generator, a manual reset input, and both activehigh and active-low reset outputs. The undervoltage
detector compares VDD against a fixed threshold. Ten
factory-programmed thresholds are available.
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The reset outputs are asserted for no less than 140ms at
power-on and any time the input voltage drops below the
reference voltage. It remains asserted for the timeout
period after the input voltage subsequently rises back
above the threshold boundary. A reset can be generated
at any time by asserting the manual reset input, /MR. This
reset output will remain active at least 140ms after the
release of /MR. The /MR input can also be used to daisychain the MIC2775 onto existing power monitoring circuitry
or other supervisors. Hysteresis is included to prevent
chattering due to noise. Typical suppy current is an ultralow 3.5µA.
Datasheets and support documentation are available on
Micrel’s website at: www.micrel.com.
Monitors power supply for undervoltage conditions
Choice of factory-programmed thresholds
Generates 140ms (minimum) power-on reset pulse
Manual reset capability
Both active-high and active-low reset outputs
/RST output valid down to 1.2V
Ultra-low supply current, 3.5µA typical
Rejects brief input transients
No external components
For extended temperature range see Micrel’s MAX825
®
IttyBitty 5-pin SOT-23 package
Applications
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Monitoring processor core and input/output voltages
Computer systems
PDAs, handheld PCs
Embedded controllers
Telecommunications systems
Power supplies
Typical Application
IttyBitty is a registered trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
March 23, 2015
Revision 4.0
Micrel, Inc.
MIC2775
Ordering Information
(1,2)
Part Number
MIC2775-XXYM5
(1,3)
Marking
UJXX
Junction Temperature Range
–40°C to +85°C
Package
(4)
SOT-23-5
Note:
1. XX = Voltage Code, see Part Numbering Conventions below. There are ten standard versions available with an order increment of 3,000 pieces.
Samples of standard versions are normally available from stock. Contact factory for information on non-standard versions. Available in tape-and-reel
only.
2. Order entry part number add a space, then TR. Example: MIC2775-22YM5 TR.
3. Underbar (__) symbol may not be to scale.
4. Standard reel SOT-23: Reel diameter is 7 inches, hub diameter is 2 inches, width is 8mm.
Part Numbering Conventions
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MIC2775
Pin Configuration
SOT-23-5 (M5)
(Top View)
Pin Description
Pin Number
Pin Name
1
/RST
Digital (Output): Asserted low whenever VDD falls below the reference voltage. It will remain
asserted for no less than 140ms after VDD returns above the threshold limit.
2
GND
Ground.
3
RST
Digital (Output): Asserted high whenever VDD falls below the reference voltage. It will remain
asserted for no less than 140ms after VDD returns above the threshold limit.
4
/MR
Digital (Input): Driving this pin low initiates an immediate and unconditional reset. Assuming VDD
is above the threshold when /MR is released (returns high), the reset output will be de-asserted
no less than 140ms later. /MR has an internal pull-up to VDD and may be left open if unused.
5
VDD
Analog (Input): Power supply input and the voltage being monitored.
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Pin Function
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Micrel, Inc.
MIC2775
Absolute Maximum Ratings(5)
Operating Ratings(6)
Supply Voltage (VDD) .................................... –0.3V to +7.0V
Output Voltage (V/MR) ................................... –0.3V to +7.0V
RST, (/RST) Current ................................................... 20mA
Storage Temperature (Ts)......................... –65°C to +150°C
(7)
ESD Rating ............................................................... 1.5kV
Supply Voltage (VDD) .................................... +1.5V to +5.5V
Input Voltage (V/MR) ...................................... –0.3V to +6.0V
Ambient Temperature (TA) .......................... –40°C to +85°C
Package Thermal Resistance (θJA) ........................ 256°C/W
Electrical Characteristics(8)
TA = 25°C, bold values indicate –40°C≤ TA ≤ +85°C, unless noted.
Symbol
Parameter
Condition
Min.
IDD
Supply Current
VDD = VTH + 1.6%, /MR, RST, /RST open,
Typ.
Max.
3.5
Units
µA
VDD Voltage Threshold
VTH1.5%
Undervoltage Threshold on
VDD
VHYST
Hysteresis Voltage
VTH
VTH+
1.5%
V
1
%
20
µs
RST, /RST Outputs
tPROP
Propagation Delay
tRST
Reset Pulse Width
VOL
RST or /RST Output Voltage
Low
VOH
RST or /RST Output Voltage
High
VDD = VTH + 1.5% + 100mV to
VDD = VTH – 1.5% - 100mV
140
280
ms
ISINK = 1.6mA; VDD ≥ 1.6V
0.3
V
ISINK = 100µA; VDD ≥ 1.2V; Note 9
0.3
V
ISOURCE = 500µA; VDD ≥ 1.5V
0.8VDD
V
ISOURCE = 10µA; VDD ≥ 1.2V; Note 9
0.8VDD
V
0.7VDD
V
/MR Input
VIH
Input High Voltage
VIL
Input Low Voltage
tPROP
Propagation Delay
From V/MR < (VIL – 100mV)
5
µs
tMIN
Minimum Input Pulse Width
Reset occurs, V/MR < VIL
33
ns
IPU
Internal Pull-up Current
100
nA
IIN
Input Current, /MR
100
nA
0.3VDD
V/MR < VIL
V
Notes:
5. Exceeding the absolute maximum ratings may damage the device.
6. The device is not guaranteed to function outside its operating ratings.
7. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.
8. Specification for packaged product only.
9. VDD operating range is 1.5V to 5.5V. Output is guaranteed to be asserted down to VDD = 1.2V.
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MIC2775
Timing Diagram
Note: Propagation delays not shown for clarity.
A = The MIC2775 ignores very brief transients. See the Application Information section for details.
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MIC2775
Functional Diagram
Functional Description
/MR, Manual Reset Input
The ability to initiate a reset via external logic or a manual
switch is provided in addition to the MIC2775’s automatic
supervisory functions. Driving the /MR input to a logic-low
causes an immediate and unconditional reset to occur.
Assuming VDD is within tolerance when /MR is released
(returns high), the reset outputs will be de-asserted no
less than tRST later. /MR may be driven by a logic signal
or mechanical switch. Typically, a momentary pushbutton switch is connected such that /MR is shorted to
ground when the switch contact close. The switch may be
connected directly between /MR and GND. /MR has an
internal 100nA pull-up current to VDD and may be left
open if unused.
VDD Input
The VDD pin is both the power supply terminal and a
monitored input voltage. The voltage at this pin is
continually compared against the internal reference. The
trip-point at which a reset occurs is factory-programmed.
A reset is triggered if and when VDD falls below the trippoint. Hysteresis is employed to prevent chattering due to
noise. The comparator on the VDD input is relatively
immune to very brief negative-going transients.
RST, /RST Reset Outputs
Typically, the MIC2775 is used to monitor the power
supply of intelligent circuits such as microcontrollers and
microprocessors. By connecting the appropriate reset
output of an MIC2775 to the reset input of a µC or µP, the
processor will be properly reset at power-on, powerdown, and brown-out conditions. In addition, asserting
/MR, the manual reset input, will activate the reset
function.
The reset outputs are asserted any time /MR is asserted
or if VDD drops below the threshold voltage. The reset
outputs remain asserted for tRST(min) after VDD
subsequently returns above the threshold boundary
and/or /MR is released. A reset pulse is also generated at
power-on. Hysteresis is included in the comparator to
prevent chattering of the outputs due to noise.
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MIC2775
Application Information
Transient Response
The MIC2775 is inherently immune to very short
negative-going glitches. Very brief transients may exceed
the voltage threshold without tripping the output.
Ensuring Proper Operation at Low Supply
At VDD levels below 1.2V, the MIC2775’s /RST output
cannot turn on sufficiently to produce a valid logic-low on
/RST. In this situation, circuits driven by /RST could be
allowed to float, causing undesired operation. In most
cases, however, it is expected that the circuits driven by
the MIC2775 will be similarly inoperative at VDD ≤ 1.2V.
In general, as shown in Figure 3, the narrower the
transient, the deeper the threshold overdrive that will be
ignored by the MIC2775. The graph represents the
typical allowable transient duration for a given amount of
threshold overdrive that will not generate a reset.
If a given application requires that /RST be valid below
VDD = 1.2V, this can be accomplished by adding a pulldown resistor to the /RST output. A value or 100kΩ is
recommended as this is usually an acceptable
compromise of quiescent current and pull-down current.
The resistor’s value is not critical, however. See Figure 1.
Figure 3. Typical VDD Transient Response
Figure 1. MIC2775 Valid /RST Below 1.2V
The statements above also apply to the MIC2775’s RST
output. That is, to ensure valid RST signal levels when
VDD < 1.2V, a pull-up resistor (as opposed to a pull-down)
should be added to the RST output. A value or 100kΩ is
typical for this application, as well. See Figure 2.
Figure 2. MIC2775 Valid RST Below 1.2V
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Micrel, Inc.
MIC2775
Package Information and Recommended Landing Pattern(10)
SOT-23-5 (M5)
Note:
10. Package information is correct as of the publication date. For updates and most current information, go to www.micrel.com.
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Micrel, Inc.
MIC2775
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
Micrel, Inc. is a leading global manufacturer of IC solutions for the worldwide high performance linear and power, LAN, and timing & communications
markets. The Company’s products include advanced mixed-signal, analog & power semiconductors; high-performance communication, clock
management, MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches, and physical layer transceiver ICs. Company
customers include leading manufacturers of enterprise, consumer, industrial, mobile, telecommunications, automotive, and computer products.
Corporation headquarters and state-of-the-art wafer fabrication facilities are located in San Jose, CA, with regional sales and support offices and
advanced technology design centers situated throughout the Americas, Europe, and Asia. Additionally, the Company maintains an extensive network
of distributors and reps worldwide.
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this datasheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
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