LM3711YSBP-308 [TI]
1-CHANNEL POWER SUPPLY SUPPORT CKT, PBGA9, MICRO, SMD-9;
| 型号： | LM3711YSBP-308 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PBGA9, MICRO, SMD-9 |
| 文件： | 总18页 (文件大小：305K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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November 2000
LM3710/LM3711
Microprocessor Supervisory Circuits with Power Fail
Input, Low Line Output, Manual Reset and Watchdog
Timer
General Description
Features
n Standard Reset Threshold voltage: 3.08V
n Custom Reset Threshold voltages: For other voltages
between 2.2V and 5.0V in 10mV increments, contact
National Semiconductor Corp.
The LM3710/LM3711 series of microprocessor supervisory
circuits provide the maximum flexibility for monitoring power
supplies and battery controlled functions in systems without
backup batteries. The LM3710/LM3711 series are available
in MSOP-10 and 9-bump micro SMD packages.
n No external components required
Built-in features include the following:
n Manual-Reset input
n RESET (LM3710) or RESET (LM3711) outputs
n Precision supply voltage monitor
n Factory programmable Reset and Watchdog Timeout
Delays
Reset: Reset is asserted during power-up, power-down, and
brownout conditions. RESET is guaranteed down to VCC of
1.0V.
Manual Reset Input: An input that asserts reset when pulled
low.
n Separate Power Fail comparator
n Available in micro SMD package for minimum footprint
Power-Fail Input: A 1.225V threshold detector for power fail
±
±
warning, or to monitor a power supply other than VCC
.
n
n
0.5% Reset threshold accuracy at room temperature
2% Reset threshold accuracy over temperature
Low Line Output: This early power failure warning indicator
goes low when the supply voltage drops to a value which is
2% higher than the reset threshold voltage.
extremes
n Reset assertion down to 1V VCC (RESET option only)
n 28 µA VCC supply current
Watchdog Timer: The WDI (Watchdog Input) monitors one of
the µP’s output lines for activity. If no output transition occurs
during the watchdog timeout period, reset is activated.
Applications
n Embedded Controllers and Processors
n Intelligent Instruments
n Automotive Systems
n Critical µP Power Monitoring
Typical Application
DS200118-3
© 2000 National Semiconductor Corporation
DS200118
www.national.com
Connection Diagram
MSOP-10
Top View
(looking from the coating side)
micro SMD 9 Bump Package
BPA09
DS200118-2
DS200118-1
Pin Description
Pin No.
Name
Function
micro
SMD
1
MSOP
2
MR
Manual-Reset input. When MR is less than VMRT (Manual Reset Threshold)
RESET/RESET is engaged.
2
3
1
VCC
Power Supply input.
10
RESET
Reset Logic Output. Pulses low for tRP (Reset Timeout Period) when triggered, and
stays low whenever VCC is below the reset threshold or when MR is below VMRT. It
remains low for tRP after either VCC rises above the reset threshold, or after MR input
rises above VMRT (LM3710 only).
RESET
PFO
Reset Logic Output. RESET is the inverse of RESET (LM3711 only).
4
5
8
7
Power-Fail Logic Output. When PFI is below VPFT, PFO goes low; otherwise, PFO
remains high.
LLO
Low-Line Logic Output. Early Power-Fail warning output. Low when VCC falls below
VLLOT (Low-Line Output Threshold). This output can be used to generate an NMI
(Non-Maskable Interrupt) to provide an early warning of imminent power-failure.
6
7
5
4
GND
WDI
Ground reference for all signals.
Watchdog Input Transition Monitor: If no transition activity occurs for a period exceeding
tWD (Watchdog Timeout Period), reset is engaged.
8
9
3
PFI
NC
Power-Fail Comparator Input. When PFI is less than VPFT (Power-Fail Reset Threshold),
the PFO goes low; otherwise, PFO remains high.
6, 9
No Connect. Test input used at factory only. Leave floating.
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2
Block Diagram
DS200118-5
3
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Ordering Information
DS200118-4
*
For other voltages between 2.2V and 5.0V, please contact National Semiconductor sales office.
LM3710/LM3711
Package
micro
Reset
Timeout
Period
Watchdog
Timeout
Period
Package
Part Number
Output
Marking
MSOP
SMD
LM3710XQBP-308
LM3710XQBPX-308
LM3710XQMM-308
LM3710XQMMX-308
LM3711XQBP-308
LM3711XQBPX-308
LM3711XQMM-308
LM3711XQMMX-308
totem-pole
totem-pole
totem-pole
totem-pole
totem-pole
totem-pole
totem-pole
totem-pole
200ms
200ms
200ms
200ms
200ms
200ms
200ms
200ms
1600ms
1600ms
1600ms
1600ms
1600ms
1600ms
1600ms
1600ms
x
x
%%37
%%37
R37B
R37B
%%38
%%38
R38B
R38B
x
x
x
x
x
x
%% is the datecode and will vary with time.
Table Of Functions
Part
Active
Low
Reset
x
Active
High
Output
Reset
Timeout
Watchdog
Timeout
Manual
Reset
Power Fail
Low
Line
Output
x
Number
(X = totem-pole)
(Y = open-drain)
Comparator
Reset
Period
Period
*
LM3710
LM3711
X, Y
X
Customized
Customized
Customized
Customized
x
x
x
x
x
x
*
= available upon request. Contact National
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4
Absolute Maximum Ratings (Note 1)
Power Dissipation
(Note 3)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Operating Ratings (Note 1)
Temperature Range
−40˚C ≤ TJ ≤ 85˚C
Supply Voltage (VCC
All Other Inputs
)
−0.3V to 6.0V
−0.3V to VCC + 0.3V
ESD Ratings (Note 2)
Human Body Model
Machine Model
1.5kV
150V
LM3710/LM3711 Series Electrical Characteristics
Limits in the standard typeface are for TJ = 25˚C and limits in boldface type apply over full operating range. Unless other-
wise specified: VCC = +2.2V to 5.5V.
Symbol
POWER SUPPLY
VCC Operating
Parameter
Conditions
Min
Typ
Max
Units
LM3710
LM3711
1.0
1.2
5.5
5.5
50
Voltage Range:
VCC
V
ICC
VCC Supply
Current
All inputs = VCC; all outputs floating
28
µA
RESET THRESHOLD
VRST
Reset Threshold
VCC falling
−0.5
+0.5
−2
+2
VRST
%
VCC falling: TA = 0˚C to 70˚C
−1.5
+1.5
VRSTH
tRP
Reset Threshold
Hysteresis
0.0032•VRST
mV
Reset Timeout
Period
Reset Timeout Period = E, J, N, S
Reset Timeout Period = F, K, P, T
Reset Timeout Period = G, L, Q, U
Reset Timeout Period = H, M, R, V
1
20
140
1120
1.4
28
200
1600
2
40
280
2240
ms
µs
tRD
VCCto Reset
Delay
VCCfalling at 1mV/µs
20
RESET (LM3711)
VOL RESET
>
VCC 2.25V, ISINK = 900µA
0.3
0.3
0.4
>
VCC 2.7V, ISINK = 1.2mA
V
>
VCC 4.5V, ISINK = 3.2mA
>
VOH
RESET
VCC 1.2V, ISOURCE = 50µA
0.8 VCC
0.8 VCC
>
VCC 1.8V, ISOURCE = 150µA
>
VCC 2.25V, ISOURCE = 300µA
0.8 VCC
V
>
VCC 2.7V, ISOURCE = 500µA
0.8 VCC
>
VCC 4.5V, ISOURCE = 800µA
VCC − 1.5V
ILKG
Output Leakage
Current
VRESET = 5.5V
1.0
µA
RESET (LM3710)
VOL RESET
>
VCC 1.0V, ISINK = 50µA
0.3
0.3
0.3
0.3
0.4
>
VCC 1.2V, ISINK = 100µA
>
VCC 2.25V, ISINK = 900µA
>
VCC 2.7V, ISINK = 1.2mA
V
>
VCC 4.5V, ISINK = 3.2mA
>
VOH
RESET
VCC 2.25V, ISOURCE = 300µA
0.8 VCC
0.8 VCC
>
VCC 2.7V, ISOURCE = 500µA
>
VCC 4.5V, ISOURCE = 800µA
VCC − 1.5V
5
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LM3710/LM3711 Series Electrical Characteristics (Continued)
Limits in the standard typeface are for TJ = 25˚C and limits in boldface type apply over full operating range. Unless other-
wise specified: VCC = +2.2V to 5.5V.
Symbol
WDI
Parameter
Conditions
Min
−1
Typ
Max
+1
Units
WDI
Watchdog Input
Current
µA
WDIT
tWD
Watchdog Input
Threshold
0.2•VCC
1.225
0.8•VCC
V
Watchdog
Timeout Period
Watchdog Timeout Period = E, F, G, H
Watchdog Timeout Period = J, K, L, M
Watchdog Timeout Period = N, P, Q, R
Watchdog Timeout Period = S, T, U, V
4.3
71
1120
17900
6.2
102
1600
25600
9.3
153
2400
38400
ms
PFI/MR
VPFT
PFI Input
Threshold
1.200
2.0
1.225
1.250
0.8
V
VMRT
MR Input
Threshold
MR, Low
V
MR, High
VPFTH
/
PFI/MR
PFI/MR falling: VCC = VRST MAX to 5.5V
0.0032•VRST
mV
VMRTH
Threshold
Hysteresis
IPFI
RMR
tMD
Input Current
(PFI only)
−75
35
75
75
nA
kΩ
µS
µS
MR Pull-up
Resistance
56
12
MR to Reset
Delay
tMR
MR Pulse Width
25
PFO, LLO
VOL
>
PFO, LLO
Output Voltage
VCC 2.25V, ISINK = 900µA
0.3
0.3
0.4
>
VCC 2.7V, ISINK = 1.2mA
>
VCC 4.5V, ISINK = 3.2mA
V
V
>
VOH
VCC 2.25V, ISOURCE = 300µA
0.8 VCC
0.8 VCC
>
VCC 2.7V, ISOURCE = 500µA
>
VCC 4.5V, ISOURCE = 800µA
VCC − 1.5V
LLO OUTPUT
VLLOT
LLO Output
1.01•VRST
1.02•VRST
1.03•VRST
Threshold
(VLLO − VRST
VCC falling)
,
VLLOTH
Low-Line
Comparator
Hysteresis
0.0032•VRST
mV
µs
tCD
Low-Line
Comparator
Delay
VCC falling at 1mV/µs
20
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6
LM3710/LM3711 Series Electrical Characteristics (Continued)
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The
guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed
conditions.
Note 2: The Human Body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200pF capacitor discharged
directly into each pin.
Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, T (MAX), the junction-to-ambient thermal resistance, θ , and
J
J-A
the ambient temperature, T . The maximum allowable power dissipation at any ambient temperture is calculated using:
A
Where the value of θ
for the MSOP-10 package is 195˚C/W in a typical PC board mounting and the micro SMD package is 220˚C/W.
J-A
7
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Typical Performance Characteristics
Supply Current vs Supply Voltage
3.3V Supply Current vs Temperature
DS200118-11
DS200118-15
Normalized Reset Threshold Voltage vs Temperature
Reset Timeout Period vs VCC
DS200118-12
DS200118-32
Reset Timeout Period vs Temperature
Max. Transient Duration vs Reset Comparator
Overdrive (VCC = 3.3V)
DS200118-10
DS200118-16
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8
Typical Performance Characteristics (Continued)
Watchdog Timeout Period vs Temperature
(tWD programmed as 6.2ms)
Low-Line Comparator Propagation Delay vs
Temperature
DS200118-14
DS200118-13
Power-Fail Comparator (PFI/PFO)
Circuit Information
The PFI is compared to a 1.225V internal reference, VPFT. If
PFI is less than VPFT, the Power Fail Output PFO drops low.
The power-fail comparator signals a falling power supply,
and is driven typically by an external voltage divider that
senses either the unregulated supply or another system
supply voltage. The voltage divider generally is chosen so
the voltage at PFI drops below VPFT several milliseconds
before the main supply voltage drops below the reset thresh-
old, providing advanced warning of a brownout.
Reset Output
The Reset input of a µP initializes the device into a known
state. The LM3710/LM3711 microprocessor supervisory cir-
cuits assert a forced reset output to prevent code execution
errors during power-up, power-down, and brownout condi-
tions.
>
RESET is guaranteed valid for VCC
1V. Once VCC ex-
ceeds the reset threshold, an internal timer maintains the
output for the reset timeout period. After this interval, reset
goes high. The LM3710 offers an active-low RESET; The
LM3711 offers an active-high RESET.
The voltage threshold is set by R1 and R2 and is calculated
as follows:
Any time VCC drops below the reset threshold (such as
during a brownout), the reset activates. When VCC again
rises above the reset threshold, the internal timer starts.
Reset holds until VCC exceeds the reset threshold for longer
than the reset timeout period. After this time, reset releases.
Note this comparator is completely separate from the rest of
the circuitry, and may be employed for other functions as
needed.
The Manual Reset input (MR) will initiate a forced reset also.
See the Manual Reset Input section.
Low-Line Output (LLO)
The low-line output comparator is typically used to provide a
non-maskable interrupt to a µP when VCC begins falling. LLO
monitors VCC and goes low when VCC falls below VLLOT
Reset Threshold
The LM3710/LM3711 family is available with a reset voltage
of 3.08V. Other reset thresholds in the 2.20V to 5.0V range,
in steps of 10 mV, are available; contact National Semicon-
ductor for details.
(typically 1.02 • VRST) with hysteresis of 0.0032 • VRST
.
Watchdog Timer Input (WDI)
The watchdog timer input monitors one of the microproces-
sor’s output lines for activity. Each time a transition occurs on
this monitored line, the watchdog counter is reset. However,
if no transition occurs and the timeout period is reached, the
LM3712/LM3713 assumes that the microprocessor has
locked up and the reset output is activated.
Manual Reset Input (MR)
Many µP-based products require a manual reset capability,
allowing the operator to initiate a reset. The MR input is fully
debounced and provides an internal 56 kΩ pull-up. When the
MR input is pulled below VMRT (1.225V) for more than 25 µs,
reset is asserted after a typical delay of 12 µs. Reset remains
active as long as MR is held low, and releases after the reset
timeout period expires after MR rises above VMRT. Use MR
with digital logic to assert or to daisy chain supervisory
circuits. It may be used as another low-line comparator by
adding a buffer.
WDI is a high impedance input.
Special Precautions for the micro SMD Package
As with most integrated circuits, the LM3710 and LM3711
are sensitive to exposure from visible and infrared (IR) light
radiation. Unlike a plastic encapsulated IC, the micro SMD
package has very limited shielding from light, and some
sensitivity to light reflected from the surface of the PC board
or long wavelength IR entering the die from the side may be
experienced. This light could have an unpredictable affect on
9
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Circuit Information (Continued)
the electrical performance of the IC. Care should be taken to
shield the device from direct exposure to bright visible or IR
light during operation.
Micro SMD Mounting
The micro SMD package requires specific mounting tech-
niques which are detailed in National Semiconductor Appli-
cation Note # 1112. Referring to the section Surface Mount
Technology (SMT) Assembly Considerations, it should be
noted that the pad style which must be used with the 9-pin
package is the NSMD (non-solder mask defined) type.
For best results during assembly, alignment ordinals on the
PC board may be used to facilitate placement of the micro
SMD device.
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10
Timing Diagrams
DS200118-28
FIGURE 1. LM3710/LM3711 Reset Time with MR and WDI
DS200118-29
FIGURE 2. LLO Output
DS200118-30
FIGURE 3. PFI Comparator Timing Diagram
11
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Typical Application Circuits
DS200118-18
FIGURE 4. Monitoring Two Critical Supplies
DS200118-19
FIGURE 5. Monitoring Two Supplies plus Manual Reset
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12
Typical Application Circuits (Continued)
DS200118-20
FIGURE 6. Monitoring Dual Supplies plus External Fault Input
DS200118-21
Note: MR input with its 1.225V nominal threshold, may monitor an additional supply voltage. An internal 56 kΩ pull-up resistor is
included on this input.
FIGURE 7. Microprocessor Supervisor with Early Warning Detector
13
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Typical Application Circuits (Continued)
DS200118-40
FIGURE 8. LM3710 Long Period oscillator
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14
Physical Dimensions inches (millimeters) unless otherwise noted
10 Lead MSOP Package
NS Package Number MUB10A
15
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
NOTES: UNLESS OTHERWISE SPECIFIED
1. EPOXY COATING
2. 63Sn/37Pb EUTECTIC BUMP
3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD.
4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE
NUMBERED COUNTER CLOCKWISE.
5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS
PACKAGE LENGTH AND X3 IS PACKAGE HEIGHT.
6.NO JEDEC REGISTRATION AS OF AUG.1999.
9 bump micro SMD Package
NS Package Number BPA09FFB
The dimensions of X1, X2 and X3 are given below
X1 = 1.412mm
X2 = 1.412mm
X3 = 0.850mm
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16
Notes
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
National Semiconductor
Corporation
Americas
Tel: 1-800-272-9959
Fax: 1-800-737-7018
Email: support@nsc.com
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Europe
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Response Group
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www.national.com
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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