LTC2910
Octal Positive/Negative
Voltage Monitor
DESCRIPTION
FEATURES
■
■
■
■
■
■
■
■
■
■
The LTC®2910 is an octal input voltage monitor intended
for monitoring multiple voltages in a variety of applications. Each input has a nominal 0.5V threshold, featuring
1.5% tight threshold accuracy over the entire operating
temperature range. Glitch filtering ensures reliable reset
operation without false or noisy triggering.
8 Low Voltage Adjustable Inputs (0.5V)
Guaranteed Threshold Accuracy: ±1.5%
Input Glitch Rejection
Pin Selectable Input Polarity Allows
Negative and OV Monitoring
Buffered 1V Reference Output
Adjustable Reset Timeout with Timeout Disable
50μA Quiescent Current
Open Drain RST and RST Outputs
Guaranteed RST and RST for VCC ≥ 1V
Available in 16-Lead SSOP and 16-Lead
(5mm × 3mm) DFN Packages
Polarity selection and a buffered reference allow monitoring up to two separate negative voltages. A three state
input pin allows setting the polarity of two inputs without
requiring any external components.
The LTC2910 provides a precise, versatile, space-conscious, micropower solution for voltage monitoring.
APPLICATIONS
■
■
■
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Desktop and Notebook Computers
Network Servers
Core, I/O Voltage Monitors
TYPICAL APPLICATION
Octal Supply Monitor, 10% Tolerance, 12V, 5V (x2), 3.3V (x2), 2.5V, 1.8V, 1.2V
Typical Transient Duration
vs Comparator Overdrive
12V
700
3.3V
2.5V
POWER
SUPPLIES 1.8V
1.2V
5V
3.3V
54.9k
88.7k
11k
11k
V8
12.7k
11k
V7
24.9k
11k
V6
39.2k
11k
V5
54.9k
11k
V4
88.7k
11k
V3
TMR
DIS
V2
RST
600
500
RESET OCCURS
ABOVE CURVE
400
300
200
VCC = 6V
100
VCC = 2.3V
0
1
10
100
0.1
COMPARATOR OVERDRIVE PAST THRESHOLD (%)
V1
VCC
RST
SYSTEM
11k
LTC2910
GND
226k
TYPICAL TRANSIENT DURATION (μs)
5V
0.1μF
2910 TA01b
SEL
1nF
TIMEOUT = 8.5ms
2910 TA01
2910fc
1
LTC2910
ABSOLUTE MAXIMUM RATINGS
(Note 1, 2)
Terminal Voltages
VCC (Note 3)............................................. –0.3V to 6V
RST, RST ................................................ –0.3V to 16V
TMR ..........................................–0.3V to (VCC + 0.3V)
Vn, DIS, SEL ......................................... –0.3V to 7.5V
Terminal Current
IVCC ....................................................................10mA
Reference Load Current (IREF) ...........................±1mA
IRST/RST..............................................................10mA
Operating Temperature Range
LTC2910C ................................................ 0°C to 70°C
LTC2910I.............................................. –40°C to 85°C
LTC2910H .......................................... –40°C to 125°C
Storage Temperature Range
SSOP, DFN.......................................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
SSOP ................................................................ 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
TOP VIEW
V1
1
16 VCC
V2
2
15 TMR
V3
3
14 SEL
V4
4
13 DIS
V5
5
V6
6
11 RST
V7
7
10 REF
V8
8
9
17
12 RST
GND
DHC16 PACKAGE
16-LEAD (5mm × 3mm) PLASTIC DFN
TJMAX = 150°C, θJA = 43.5°C/W
EXPOSED PAD (PIN 17) PCB GND CONNECTION OPTIONAL
V1
1
16 VCC
V2
2
15 TMR
V3
3
14 SEL
V4
4
13 DIS
V5
5
12 RST
V6
6
11 RST
V7
7
10 REF
V8
8
9
GND
GN16 PACKAGE
16-LEAD PLASTIC SSOP
TJMAX = 150°C, θJA = 110°C/W
ORDER PART NUMBER
DHC16 PART MARKING*
LTC2910CDHC
LTC2910IDHC
LTC2910HDHC
2910
2910
2910
ORDER PART NUMBER
GN16 PART MARKING*
LTC2910CGN
LTC2910IGN
LTC2910HGN
2910
2910I
2910H
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
*The temperature grade is identified by a label on the shipping container.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 3.3V, Vn = 0.55V, SEL = VCC, DIS = OPEN unless otherwise noted.
(Note 2)
SYMBOL
PARAMETER
CONDITIONS
VSHUNT
VCC Shunt Regulator Voltage
ICC = 5mA
ΔVSHUNT
VCC Shunt Regulator Load Regulation
VCC
Supply Voltage
MIN
TYP
MAX
●
6.2
6.6
6.9
–40°C < TA 0.5V
●
1
2
3
μA
VTMR = 0V
●
–1.3
–2.1
–2.8
μA
–40°C < TA < 125°C
●
–1.2
–2.1
–2.8
μA
VTMR = 1.6V
●
1.3
2.1
2.8
μA
2.8
–40°C < TA < 125°C
●
1.2
2.1
VTMR(DIS)
Timer Disable Voltage
Referenced to VCC
●
–180
–270
VOH
Output Voltage High RST/RST
VCC = 2.3V, IRST/RST = –1μA
●
1
VOL
Output Voltage Low RST/RST
VCC = 2.3V, IRST/RST = 2.5mA
VCC = 1V, IRST = 100μA
●
μA
mV
V
0.1
0.01
0.3
0.15
V
V
0.4
V
Three-State Input SEL
Low Level Input Voltage
●
VIH
High Level Input Voltage
●
1.4
VZ
Pin Voltage when Left in Hi-Z State
ISEL = ±10μA
●
0.6
0.9
1.1
V
–40°C < TA < 125°C
●
0.6
0.9
VIL
ISEL
SEL High, Low Input Current
ISEL(MAX)
Maximum SEL Input Current
SEL tied to either VCC or GND
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: All currents into pins are positive; all voltages are referenced to
GND unless otherwise noted.
V
1.2
V
●
±25
μA
●
±30
μA
Note 3: VCC maximum pin voltage is limited by input current. Since the
VCC pin has an internal 6.5V shunt regulator, a low impedance supply that
exceeds 6V may exceed the rated terminal current. Operation from higher
voltage supplies requires a series dropping resistor. See Applications
Information.
2910fc
3
LTC2910
TIMING DIAGRAM
Vn Positive Monitor Timing
Vn
VRT
tPROP
RST
1V
RST
1V
tRST
2910 TD01
Vn Positive Monitor Timing (TMR strapped to VCC)
Vn
VRT
tPROP
RST
1V
RST
1V
tPROP
2910 TD03
Vn Negative Monitor Timing
Vn
VRT
tPROP
RST
1V
RST
1V
tRST
2910 TD02
Vn Negative Monitor Timing (TMR strapped to VCC)
Vn
VRT
tPROP
RST
1V
RST
1V
tPROP
2910 TD04
2910fc
4
LTC2910
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at TA = 25°C and VCC = 3.3V
unless otherwise noted. (Note 2)
Input Threshold Voltage vs
Temperature
VCC Shunt Voltage vs
Temperature
Supply Current vs Temperature
65
0.505
6.8
60
0.503
6.7
10mA
6.6
5mA
6.5
2mA
VCC = 5V
0.502
0.500
0.499
VCC (V)
55
0.501
ICC (μA)
THRESHOLD VOLTAGE, VRT (V)
0.504
VCC = 3.3V
50
1mA
45
0.498
0.497
6.4
VCC = 2.3V
40
200μA
6.3
0.496
0.495
–50
–25
0
25
50
TEMPERATURE (°C)
35
–50
100
75
–25
25
50
0
TEMPERATURE (°C)
75
6.75
85°C
6.35
TYPICAL TRANSIENT DURATION (μs)
REFERENCE VOLTAGE, VREF (V)
VCC (V)
–40°C
1.003
1.002
1.001
1.000
0.999
0.998
0.997
0.996
6.25
–2
0
2
6
4
ICC (mA)
8
10
12
0.995
–50
–25
0
25
50
TEMPERATURE (°C)
500
RESET OCCURS
ABOVE CURVE
400
300
200
VCC = 6V
100
VCC = 2.3V
0
0.1
1
10
100
COMPARATOR OVERDRIVE PAST THRESHOLD (%)
2910 G05
2910 G06
RST Output Voltage vs VCC
RST Output Voltage vs VCC
0.8
CTMR = 1nF
5
Vn = 0.55V
SEL = VCC
VCC
11
4
10
9
8
RST VOLTAGE (V)
0.6
RST VOLTAGE (V)
RST/RST TIMEOUT PERIOD, tRST (ms)
12
600
100
75
2910 G04
Reset Time-Out Period vs
Temperature
100
700
1.004
25°C
75
Transient Duration vs Comparator
Overdrive
1.005
6.55
0
25
50
TEMPERATURE (°C)
2910 G03
Buffered Reference Voltage vs
Temperature
VCC Shunt Voltage vs ICC
6.65
–25
2910 G02
2910 G01
6.45
6.2
–50
100
0.4
RST WITH
10k PULL-UP
3
2
0.2
RST WITHOUT
10k PULL-UP
7
6
–50
0
–25
0
25
50
TEMPERATURE (°C)
75
100
2910 G07
0
0.8
0.2
0.4
0.6
SUPPLY VOLTAGE, VCC (V)
1
1.0
2910 G08
0
0
1
2
3
4
SUPPLY VOLTAGE, VCC (V)
5
2910 G09
2910fc
5
LTC2910
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at TA = 25°C and VCC = 3.3V
unless otherwise noted. (Note 2)
RST/RST Voltage Output Low vs
Output Sink Current
RST, ISINK vs VCC
1.0
85°C
4
0.8
25°C
RST AT 150mV
3
2
RST AT 50mV
1
0
10000
RST/RST TIMEOUT PERIOD, tRST (ms)
Vn = 0.45V
SEL = VCC
RST/RST, VOL (V)
PULL-DOWN CURRENT, IRST (mA)
5
Reset Timeout Period vs
Capacitance
–40°C
0.6
0.4
0.2
0
0
1
2
3
4
SUPPLY VOLTAGE, VCC (V)
5
0
5
10
15
20
IRST/RST (mA)
2910 G10
25
30
2910 G11
1000
100
10
1
0.1
1
10
100
TMR PIN CAPACITANCE, CTMR (nF)
1000
2910 G12
PIN FUNCTIONS
DIS (Pin 13): Output Disable Input. Disables the RST and
RST output pins. When DIS is pulled high, the RST and
RST pins are not asserted except during a UVLO condition.
Pin has a weak (2μA) internal pull-down to GND. Leave
pin open if unused.
Exposed Pad (Pin 17, DFN Package): Exposed pad may
be left open or connected to device ground.
GND (Pin 9): Device Ground
REF (Pin 10): Buffered Reference Output. 1V reference
used for the offset of negative-monitoring applications.
The buffered reference sources and sinks up to 1mA. The
reference drives capacitive loads up to 1nF. Larger capacitive
loads may cause instability. Leave pin open if unused.
RST (Pin 11): Open-Drain Reset Logic Output. Asserts
high when any positive polarity input voltage is below
threshold or any negative polarity input voltage is above
threshold. Held high for an adjustable delay time after all
voltage inputs are valid. Pin has a weak pull-up to VCC and
may be pulled above VCC using an external pull-up. Leave
pin open if unused.
RST (Pin 12): Open-Drain Inverted Reset Logic Output.
Asserts low when any positive polarity input voltage is
below threshold or any negative polarity input voltage is
above threshold. Held low for an adjustable delay time after
all voltage inputs are valid. Pin has a weak pull-up to VCC
and may be pulled above VCC using an external pull-up.
Leave pin open if unused.
SEL (Pin 14): Input Polarity Select Three-State Input.
Connect to VCC, GND or leave unconnected in open state
to select one of three possible input polarity combinations
(refer to Table 1).
TMR (Pin 15): Reset Delay Timer. Attach an external capacitor (CTMR) of at least 10pF to GND to set a reset delay
time of 9ms/nF. A 1nF capacitor will generate an 8.5ms
reset delay time. Tie pin to VCC to bypass timer.
V1-V6 (Pin 1, 2, 3, 4, 5 & 6): Voltage Inputs 1 through 6.
When the voltage on this pin is below 0.5V, a reset condition is triggered. Tie pin to VCC if unused.
V7-V8 (Pin 7 & 8): Voltage Inputs 7 and 8. The polarity
of the input is selected by the state of the SEL pin (refer
2910fc
6
LTC2910
PIN FUNCTIONS
to Table 1). When the monitored input is configured as a
positive voltage, a reset condition is triggered when the
pin is below 0.5V. When the monitored input is configured as a negative voltage, a reset condition is triggered
when the pin is above 0.5V. Tie pin to VCC if unused and
configured as a positive supply. Tie pin to GND if unused
and configured as a negative supply.
VCC (Pin 16): Supply Voltage. Bypass this pin to GND with
a 0.1μF (or greater) capacitor. Operates as a direct supply
input for voltages up to 6V. Operates as a shunt regulator for
supply voltages greater than 6V and must have a resistance
between the pin and the supply to limit input current to no
greater than 10mA. When used without a current-limiting
resistance, pin voltage must not exceed 6V.
BLOCK DIAGRAM
1
V1
VCC
TMR
16
15
VCC
–
+
400k
OSCILLATOR
V2
2
–
3
V3
RST
RESET DELAY
TIMER
DISABLE
+
12
–
+
UVLO
4
V4
–
+
2V
–
VCC
VCC
400k
+
RST
V5
5
11
–
+
V6
6
–
+
V7
7
–
+
V8
8
DIS
+
–
–
1V
13
2μA
+
0.5V
10
REF
1V
THREE-STATE
POLARITY
DECODER
GND
9
BUFFER
14
2910 BD
SEL
2910fc
7
LTC2910
APPLICATIONS INFORMATION
Voltage Monitoring
Table 1. Voltage Polarity Programming (VRT = 0.5V Typical)
The LTC2910 is a low power octal voltage monitoring
circuit with eight individual undervoltage monitor inputs.
A timeout period that holds a reset after all faults have
cleared is adjustable using an external capacitor and is
disabled, by tying TMR to VCC.
Each voltage monitor is compared to a fixed 0.5V reference
for detecting undervoltage conditions. When configured
to monitor a positive voltage Vm, the application is connected as shown in Figure 1. For negative inputs Vm is
connected as shown in Figure 2. RA is now connected to
the REF pin and RB remains connected to the monitored
voltage Vm.
SEL
V7 INPUT
V8 INPUT
VCC
Positive
V7 < VRT → UV
Positive
V8 < VRT → UV
Open
Positive
V7 < VRT → UV
Negative
V8 > VRT → UV
GND
Negative
V7 > VRT → UV
Negative
V8 > VRT → UV
2-Step Design Procedure
The following 2-step design procedure allows selecting
appropriate resistances to obtain the desired UV trip point
for the positive voltage monitor circuit in Figure 1 and the
negative voltage monitor circuit in Figure 2.
Using the configurations in Figures 1 and 2, a UV condition will result when the magnitude of the voltage at Vm
is less than its designed threshold.
For positive supply monitoring, Vm is the desired nominal
operating voltage, Im is the desired nominal current through
the resistive divider, and VUV is the desired undervoltage
trip point.
Polarity Selection
For negative supply monitoring, to compensate for the 1V
reference, 1V must be subtracted from Vm and VUV before
using each in the following equations.
The three-state polarity-select pin (SEL) selects one of three
possible polarity combinations for the input thresholds,
as described in Table 1. When an input is configured for
negative supply monitoring, a reset condition occurs when
the supply voltage is less negative than the configured
threshold.
The three-state input pin SEL is connected to GND, VCC, or
left unconnected during normal operation. When the pin
is left unconnected, the maximum leakage allowed from
the pin is ±10μA to ensure it remains in the open state.
Table 1 shows the three possible selections of polarity
based on the SEL pin connection.
1. Choose RA to obtain the desired UV trip point
RA is chosen to set the desired trip point for the
undervoltage monitor.
RA =
0.5V Vm
•
Im VUV
(1)
LTC2910
+
REF
+
–
–
Vm
RB
Vn
–
+
RA
RA
LTC2910
Vn
+
–
1V
–
UVn
+
RB
0.5V
+
–
UVn
0.5V
Vm
2910 F01
Figure 1. Positive UV Monitoring Configuration
2910 F02
Figure 2. Negative UV Monitoring Configuration
2910fc
8
LTC2910
APPLICATIONS INFORMATION
2. Choose RB to complete the design
current in the resistive divider is 10μA. For the negative
case, 1V is subtracted from Vm and VUV.
Once RA is known, RB is determined by:
1. Find RA to set the UV trip point of the monitor.
V
RB = m − RA
Im
(2)
RA =
If any of the variables Vm, Im, or VUV change, then both
steps must be recalculated.
Positive Voltage Monitor Example
1. Find RA to set the UV trip point of the monitor.
RA =
0.5V 5V
•
≈ 56.2k
10µA 4.5V
2. Determine RB to complete the design.
RB =
2. Determine RB to complete the design.
RB =
A positive voltage monitor application is shown in Figure
3. The monitored voltage is a 5V ±10% supply. Nominal
current in the resistive divider is 10μA.
5V
− 56.2k ≈ 499k
10µA
0.5V –5V − 1V
•
≈ 54.9k
10µA –4.5V − 1V
–5V − 1V
− 57.6k ≈ 549k
10µA
Power-Up/Down
As soon as VCC reaches 1V during power up, the RST output
asserts low and the RST output weakly pulls to VCC.
The LTC2910 is guaranteed to assert RST low and RST high
under conditions of low VCC, down to VCC = 1V. Above VCC
= 2V (2.1V maximum) the Vn inputs take control.
Once all inputs and VCC become valid, an internal timer is
started. After an adjustable delay time, RST pulls low and
RST weakly pulls high.
Threshold Accuracy
Negative Voltage Monitor Example
A negative voltage monitor application is shown in Figure
4. The monitored voltage is a –5V ±10% supply. Nominal
Reset threshold accuracy is important in a supply sensitive
system. Ideally, such a system would reset only if supply
5V
5V
VCC
VCC
5V ± 10%
RST
RST
RB
449k
LTC2910
RST
REF
RST
RA
54.9k
V7
LTC2910
V7
SEL
RA
56.2k
GND
–5V ± 10%
2910 F03
Figure 3. Positive Supply Monitor
SEL
RB
549k
GND
2910 F04
Figure 4. Negative Supply Monitor
2910fc
9
LTC2910
APPLICATIONS INFORMATION
voltages fell below the exact threshold for a specified margin. All LTC2910 inputs have a relative threshold accuracy
of ±1.5% over the full operating temperature range.
For example, when the LTC2910 is programmed to monitor a 5V input with a 10% tolerance, the desired UV trip
point is 4.5V. Because of the ±1.5% relative accuracy of
the LTC2910, the UV trip point is between 4.433V and
4.567V which is 4.5V ±1.5%.
The accuracy of the resistances chosen for RA and RB affect
the UV trip point as well. Using the example just given,
if the resistances used to set the UV trip point have 1%
accuracy, the UV trip range is between 4.354V and 4.650V.
This is illustrated in the following calculations.
The UV trip point is given as
R
VUV = 0.5V • 1+ B
RA
The two extreme conditions, with a relative accuracy of
1.5% and resistance accuracy of 1%, result in
R • 0.99
VUV(MIN) = 0.5V • 0.985 • 1+ B
RA • 1.01
and
R • 1.01
VUV(MAX) = 0.5V • 1.015 • 1+ B
RA • 0.99
For a desired trip point of 4.5V,
RB
=8
RA
Therefore,
0.99
VUV(MIN) = 0.5V • 0.985 • 1+ 8 •
= 4.354V
1.01
and
1.01
VUV(MAX) = 0.5V • 1.015 • 1+ 8 •
= 4.650V
0.99
Glitch Immunity
In any supervisory application, noise riding on the monitored DC voltage causes spurious resets. To solve this
problem without adding hysteresis, which causes a new
error term in the trip voltage, the LTC2910 lowpass filters
the output of the first stage comparator at each input.
This filter integrates the output of the comparator before
asserting the reset output logic. A transient at the input
of the comparator of sufficient magnitude and duration
triggers the output logic. The Typical Performance Characteristics section shows a graph of the Transient Duration
vs. Comparator Overdrive.
RST/RST Timing
The LTC2910 has an adjustable timeout period (tRST) that
holds RST and RST asserted after all faults have cleared.
This assures a minimum reset pulse width allowing a
settling time delay for the monitored voltage after it has
entered the valid region of operation.
When any input drops below its designed threshold, the
RST pin asserts low and the RST pin asserts high. When
all inputs recover above their designed thresholds, the
reset delay timer starts. If all inputs remain above their
designed thresholds when the timer finishes, the RST
pin weakly pulls high and the RST pin strongly pulls low.
However, if any input falls below its designed threshold
during this timeout period, the timer resets and restarts
when all inputs are above the designed thresholds.
Selecting the Reset Timing Capacitor
The reset timeout period (tRST) for the LTC2910 is adjustable to accommodate a variety of applications. Connecting
a capacitor, CTMR, between the TMR pin and ground sets
the timeout period. The value of capacitor needed for a
particular timeout period is:
CTMR = tRST • 115 • 10–9 (F/s)
The Reset Timeout Period vs. Capacitance graph found
in the Typical Performance Characteristics section shows
2910fc
10
LTC2910
APPLICATIONS INFORMATION
the desired delay time as a function of the value of the
timer capacitor. The TMR pin must have a minimum of
10pF or be tied to VCC. For long timeout periods, the only
limitation is the availability of a large value capacitor with
low leakage. Capacitor leakage current must not exceed
the minimum TMR charging current of 1.3μA. Tying the
TMR pin to VCC bypasses the timeout period.
Undervoltage Lockout
When VCC falls below 2V, the LTC2910 asserts an
undervoltage lockout (UVLO) condition. During UVLO, RST
is asserted and pulled low and RST is pulled high. When
VCC rises above 2V, RST and RST follow the same timing
procedure as an undervoltage condition on any input.
Shunt Regulator
The LTC2910 has an internal shunt regulator. The VCC pin
operates as a direct supply input for voltages up to 6V.
In this range, the quiescent current of the device remains
below a maximum of 100μA. For VCC voltages higher than
6V, the pin functions as a shunt regulator and must have a
resistance RZ between the supply and the VCC pin to limit
the current to no greater than 10mA.
When selecting this resistance value, choose an appropriate
location on the I-V curve shown in the Typical Performance
Characteristics to accommodate any variations in VCC due
to changes in current through RZ.
RST/RST Output Characteristics
The DC characteristics of the RST and RST pull-up and
pull-down strength are shown in the Typical Performance
Characteristics. Each has a weak internal pull-up to VCC and
a strong pull-down to ground. This arrangement allows
each pin to have open-drain behavior while possessing
several other beneficial characteristics. The weak pull-up
eliminates the need for an external pull-up resistor when
the rise time on this pin is not critical. On the other hand,
the open drain configuration allows for wired-OR connections and is useful when more than one signal needs to
pull down on the RST or RST lines. VCC of 1V guarantees
a maximum VOL = 0.15V.
At VCC = 1V, the weak pull-up current on RST is barely
turned on. Therefore, an external pull-up resistor of no more
than 100k is recommended on the RST pin if the state and
pull-up strength of the RST pin is crucial at very low VCC.
Note however, by adding an external pull-up resistor, the
pull-up strength on the RST pin is increased. Therefore,
if it is connected in a wired-OR connection, the pull-down
strength of any single device must accommodate this additional pull-up strength.
Output Rise and Fall Time Estimation
The RST and RST outputs have strong pull-down capability. The following formula estimates the output fall time
(90% to 10%) for a particular external load capacitance
(CLOAD):
tFALL ≈ 2.2 • RPD • CLOAD
where RPD is the on-resistance of the internal pull-down
transistor, typically 50Ω at VCC > 1V, and at room temperature (25°C). CLOAD is the external load capacitance
on the pin. Assuming a 150pF load capacitance, the fall
time is 16.5ns.
The rise time on the RST and RST pins is limited by a
400k internal pull-up resistance to VCC. A similar formula
estimates the output rise time (10% to 90%) at the RST
and RST pins:
tRISE ≈ 2.2 • RPU • CLOAD
where RPU is the pull-up resistance.
Disable
The LTC2910 allows disabling the RST and RST outputs
via the DIS pin. Pulling DIS high forces both outputs to
remain unasserted, regardless of any faults that occur
on the inputs. However, if a UVLO condition occurs, RST
asserts and pulls low, RST asserts and pulls high, but the
timeout function is bypassed. RST pulls high and RST pulls
low as soon as the UVLO condition is cleared.
DIS has a weak 2μA (typical) internal pull-down current
guaranteeing normal operation with the pin left open.
2910fc
11
LTC2910
TYPICAL APPLICATIONS
Eight UV Supply Monitor, 10% Tolerance, 12V, 5V (x2), 3.3V (x2), 2.5V, 1.8V, 1.2V
12V
5V
3.3V
2.5V
POWER
SUPPLIES 1.8V
1.2V
5V
3.3V
RB8
54.9k
RB7
88.7k
RA7
11k
RA8
11k
8
V8
RB6
12.7k
RA6
11k
7
V7
RB5
24.9k
RA5
11k
RB4
39.2k
RA4
11k
6
V6
5
V5
RB3
54.9k
RA3
11k
4
V4
RB2
88.7k
RA2
11k
3
V3
TMR
9
2
V2
1
V1
16
VCC
RST
DIS
15
13
SYSTEM
RA1
11k
LTC2910
GND
RB1
226k
RST
12
CBYP
0.1μF
SEL
11
14
CTMR
1nF
TIMEOUT = 8.5ms
2910 TA02
Six Positive and Two Negative UV Supply Monitor, 10% Tolerance,
12V, 5V, 3.3V, 2.5V, 1.8V, 1.2V, –5V, –3.3V
12V
5V
3.3V
POWER
SUPPLIES 2.5V
1.8V
1.2V
RB8
54.9k
RA8
107k
RB7
11k
RB6
12.7k
RA7
11k
RA6
11k
RB5
24.9k
RA5
11k
RB4
39.2k
RA4
11k
RB3
54.9k
RA3
11k
RB2
88.7k
RA2
11k
RB1
226k
RA1
11k
SYSTEM
8
V8
7
V7
10
REF
6
V6
5
V5
4
V4
3
V3
2
V2
VCC
LTC2910
GND
9
–3.3V
TMR
DIS
15
1
V1
13
RST
12
RST
11
SEL
16
CBYP
0.1μF
14
CTMR
22nF
TIMEOUT = 200ms
–5V
2910 TA03
2910fc
12
LTC2910
TYPICAL APPLICATIONS
Six UV and One OV/UV Supply Monitor, 10% Tolerance,
12V, 5V, 3.3V (x2), 2.5V, 1.8V, 1.2V
12V
5V
3.3V
POWER 2.5V
SUPPLIES 1.8V
1.2V
3.3V
RB7
27.4k
RA8
4.53k
RA7
1k
8
V8
RB6
12.7k
RA6
11k
7
V7
RB5
24.9k
RA5
11k
6
V6
RB4
39.2k
RA4
11k
5
V5
RB3
54.9k
RA3
11k
4
V4
RB2
88.7k
RA2
11k
3
V3
RA1
11k
2
V2
9
TMR
16
VCC
RST
DIS
15
SYSTEM
1
V1
LTC2910
GND
RB1
226k
13
RST
12
CBYP
0.1μF
SEL
11
14
CTMR
1nF
TIMEOUT = 8.5ms
2910 TA04
Six UV Supply Monitor Powered from 48V, 10% Tolerance,
48V, 5V, 3.3V, 2.5V, 1.8V, 1.2V
48V
5V
3.3V
POWER
2.5V
SUPPLIES
1.8V
1.2V
RB6
12.7k
RA6
11k
RB5
24.9k
RA5
11k
RB4
39.2k
RA4
11k
RB3
54.9k
RA3
11k
RB2
88.7k
RA2
11k
RB1
953k
RA1
11k
RZ
8.25k
8
V8
7
V7
6
V6
5
V5
4
V4
3
V3
2
V2
GND
9
TMR
15
1
V1
VCC
LTC2910
DIS
13
RST
12
RST
11
SYSTEM
SEL
16
CBYP
0.1μF
14
VCC
2910 TA05
2910fc
13
LTC2910
TYPICAL APPLICATIONS
Eight UV Supply Monitor with Manual Reset Button, 10% Tolerance,
12V, 5V (x2), 3.3V (x2), 2.5V, 1.8V, 1.2V
12V
5V
3.3V
2.5V
POWER
1.8V
SUPPLIES
1.2V
5V
3.3V
MANUAL
RESET BUTTON
(NORMALLY OPEN)
RB8
549k
RPB
10k
RB7
88.7k
RB6
12.7k
RB5
24.9k
RB4
39.2k
RB3
54.9k
RB2
88.7k
RB1
226k
SYSTEM
RA8
110k
RA7
11k
8
V8
RA6
11k
7
V7
RA5
11k
6
V6
RA4
11k
5
V5
RA3
11k
4
V4
RA2
11k
3
V3
RA1
11k
2
V2
VCC
LTC2910
GND
9
TMR
DIS
15
1
V1
13
RST
12
RST
11
16
CBYP
0.1μF
SEL
14
CTMR
22nF
TIMEOUT = 200ms
2910 TA06
2910fc
14
LTC2910
PACKAGE DESCRIPTION
DHC Package
16-Lead Plastic DFN (5mm × 3mm)
(Reference LTC DWG # 05-08-1706)
R = 0.115
TYP
5.00 ±0.10
(2 SIDES)
R = 0.20
TYP
0.65 ±0.05
3.50 ±0.05
9
0.40 ± 0.10
16
3.00 ±0.10
(2 SIDES)
1.65 ±0.05
(2 SIDES)
1.65 ± 0.10
(2 SIDES)
PACKAGE
OUTLINE
2.20 ±0.05
PIN 1
TOP MARK
(SEE NOTE 6)
PIN 1
NOTCH
(DHC16) DFN 1103
8
1
0.25 ± 0.05
0.50 BSC
0.75 ±0.05
0.200 REF
0.25 ± 0.05
0.50 BSC
4.40 ±0.05
(2 SIDES)
4.40 ±0.10
(2 SIDES)
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
NOTE:
1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC
PACKAGE OUTLINE MO-229
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
GN Package
16-Lead Plastic SSOP (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1641)
.189 – .196*
(4.801 – 4.978)
.015 ± .004
× 45°
(0.38 ± 0.10)
.007 – .0098
(0.178 – 0.249)
.016 – .050
(0.406 – 1.270)
NOTE:
1. CONTROLLING DIMENSION: INCHES
INCHES
2. DIMENSIONS ARE IN
(MILLIMETERS)
0° – 8°
TYP
.0532 – .0688
(1.35 – 1.75)
.008 – .012
(0.203 – 0.305)
TYP
.004 – .0098
(0.102 – 0.249)
.0250
(0.635)
BSC
16 15 14 13 12 11 10 9
.229 – .244
(5.817 – 6.198)
3. DRAWING NOT TO SCALE
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
.009
(0.229)
REF
.150 – .157**
(3.810 – 3.988)
1
2 3
4
5 6
7
8
.045 ±.005
.254 MIN
.0165 ± .0015
.150 – .165
.0250 BSC
RECOMMENDED SOLDER PAD LAYOUT
GN16 (SSOP) 0204
2910fc
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LTC2910
TYPICAL APPLICATION
Eight UV Supply Monitor with LED Indicator, 10% Tolerance,
12V, 5V (x2), 3.3V (x2), 2.5V, 1.8V, 1.2V
12V
5V
3.3V
2.5V
POWER 1.8V
SUPPLIES
1.2V
5V
3.3V
54.9k
88.7k
11k
11k
12.7k
11k
8
V8
7
V7
24.9k
11k
6
V6
39.2k
11k
5
V5
54.9k
11k
4
V4
88.7k
11k
3
V3
2
V2
TMR
9
DIS
15
SYSTEM
1
V1
VCC
LTC2910
GND
226k
11k
13
RST
12
RST
16
0.1μF
SEL
11
14
1nF
TIMEOUT = 8.5ms
2910 TA07
510μΩ
VCC
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC690
5V Supply Monitor, Watchdog Timer and Battery Backup
4.65V Threshold
LTC694-3.3
3.3V Supply Monitor, Watchdog Timer and Battery
Backup
2.9V Threshold
LTC2900
Programmable Quad Supply Monitor
Adjustable RESET , 10-Lead MSOP and 3mm × 3mm 10-Lead DFN
Package
LTC2901
Programmable Quad Supply Monitor
Adjustable RESET and Watchdog Timer, 16-Lead SSOP Package
LTC2902
Programmable Quad Supply Monitor
Adjustable RESET and Tolerance, 16-Lead SSOP Package, Margining
Functions
LTC2903
Precision Qual Supply Monitor
6-Lead SOT-23 Package, Ultra Low Voltage Reset
LTC2904
3-State Programmable Precision Dual Supply Monitor
Adjustable Tolerance, 8-Lead SOT-23 Package
LTC2905
3-State Programmable Precision Dual Supply Monitor
Adjustable RESET and Tolerance, 8-Lead SOT-23 Package
LTC2906
Precision Dual Supply Monitor One Selectable and One
Adjustable
Separate VCC Pin, RST/RST Outputs
LTC2907
Precision Dual Supply Monitor One Selectable and One
Adjustable
Separate VCC, Adjustable Reset Timer
LTC2908
Precision Six Supply Monitor (Four Fixed and Two
Adjustable)
8-Lead SOT-23 and DDB Packages
LTC2909
Prevision Dual Input UV, OV and Negative Voltage Monitor Separate VCC Pin, Adjustable Reset Timer, 8-Lead SOT-23 and DDB
Packages
LTC2914
Quad UV/OV Positive/Negative Voltage Monitor
Separate VCC Pin, Four Inputs, Up to Two Negative Monitors,
Adjustable Reset Timer, 16-Lead SSOP and DFN Packages
2910fc
16 Linear Technology Corporation
LT 1007 REV C • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2006
工商网监
湘ICP备2023018690号
