LINEAR TECHNOLOGY LTC2915, LTC2916 Technical data

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LTC2915/LTC2916

Voltage Supervisor with

27 Selectable Thresholds

FEATURES

9 Selectable Supply Voltages

12V, 5V, 3.3V, 2.5V, 1.8V

1.5V, 1.2V, 1.0V, +ADJ (0.5V)

3 Selectable Tolerances

–5%, –10%, –15% (LTC2915)

Manual Reset Input (LTC2916)

1.5V to 5.5V Supply Operation

6.2V Shunt Regulator for High Voltage Operation

Guaranteed Operation to 125˚C

Guaranteed Threshold Accuracy: ±1.5%

Low Quiescent Current: 30μA Typical

Power Supply Glitch Immunity

Guaranteed RST for VCC ≥ 0.8V

Low Proﬁ le (1mm) 8-Lead TSOT-23 (ThinSOTTM) and

(3mm × 2mm) DFN Packages

APPLICATIONS

Handheld Devices

Cell Phone Base Stations

Automotive Control Systems

Network Servers

Optical Networking Systems

DESCRIPTION

The LTC®2915/LTC2916 are low voltage single-supply monitors with selectable thresholds. The parts operate from 1.5V to 5.5V and consume a quiescent current of only 30μA.

Two three-state inputs select one of nine internally programmed thresholds without the need for external resistors. For the LTC2915, an additional three-state input determines the tolerance (–5%, –10%, –15%). The tolerance for the LTC2916 is ﬁ xed at –5%. Threshold accuracy is guaranteed at ±1.5% over the entire operating temperature range. Glitch ﬁ ltering ensures reliable reset operation without false triggering.

The reset timeout may be set to 200ms or adjusted using an external capacitor. A separate manual reset input on the LTC2916 allows a simple push button interface.

Operation to 125°C makes the LTC2915 and LTC2916 suitable for automotive applications.

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.

TYPICAL APPLICATION

1.8V, –5% Tolerance Supply Monitor

1.8V

0.1μF

LTC2916

RT SEL1

RST RESET

= 200ms

SEL2

GND

RST

10k

Monitor Selection Table

NOMINAL VOLTAGE SEL1 SEL2

12V V

μP

29156 TA01

5V V

3.3V V

2.5V Open V

1.8V Open Open

1.5V Open GND

1.2V GND V

1V GND Open

ADJ (0.5V) GND GND

Open

GND

29156fa

LTC2915/LTC2916

ABSOLUTE MAXIMUM RATINGS

(Notes 1, 2)

Terminal Voltages

(Note 3) .......................................... –0.3V to 5.7V

SEL1, SEL2, TOL, MR, RST .................. –0.3V to 7.5V

VM ......................................................... –0.3V to 15V

RT .............................................–0.3V to (V

+ 0.3)V

Terminal Currents

(Note 3) .......................................................±5mA

PIN CONFIGURATION

TOP VIEW

VM 1

SEL1 2

TOL/MR 3

GND 4

TS8 PACKAGE

8-LEAD PLASTIC TSOT-23

TOL FOR LTC2915

MR FOR LTC2916

= 150°C, θJA = 250°C/W

JMAX

8 V

7 SEL2 6 RT 5 RST

Operating Temperature Range

LTC2915C/LTC2916C ............................... 0°C to 70°C

LTC2915I/LTC2916I .............................. –40°C to 85°C

LTC2915H/LTC2916H ......................... –40°C to 125°C

Storage Temperature Range ................... –65°C to 150°C

TS8 Lead Temperature (Soldering, 10 sec) ........... 300°C

TOP VIEW

1GND

TOL/MR

SEL1

8-LEAD (3mm s 2mm) PLASTIC DFN

EXPOSED PAD (PIN 9) PCB GND CONNECTION OPTIONAL

DDB PACKAGE

TOL FOR LTC2915

MR FOR LTC2916 = 150°C, θJA = 76°C/W

JMAX

RST

SEL2

ORDER INFORMATION

LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE

LTC2915CTS8-1#PBF LTC2915ITS8-1#PBF LTC2915HTS8-1#PBF LTC2915CDDB-1#PBF LTC2915IDDB-1#PBF LTC2915HDDB-1#PBF

LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE

LTC2916CTS8-1#PBF LTC2916ITS8-1#PBF LTC2916HTS8-1#PBF LTC2916CDDB-1#PBF LTC2916IDDB-1#PBF LTC2916HDDB-1#PBF

Consult LTC Marketing for parts speciﬁ ed with wider operating temperature ranges. *The temperature grade is identiﬁ ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based ﬁ nish parts.

For more information on lead free part marking, go to: For more information on tape and reel speciﬁ cations, go to:

LTC2915CTS8-1#TRPBF LTC2915ITS8-1#TRPBF LTC2915HTS8-1#TRPBF LTC2915CDDB-1#TRPBF LTC2915IDDB-1#TRPBF LTC2915HDDB-1#TRPBF

LTC2916CTS8-1#TRPBF LTC2916ITS8-1#TRPBF LTC2916HTS8-1#TRPBF LTC2916CDDB-1#TRPBF LTC2916IDDB-1#TRPBF LTC2916HDDB-1#TRPBF

LT C V Q LT C V Q LT C V Q LCVR LCVR LCVR

LT D C W LT D C W LT D C W LDCX LDCX LDCX

http://www.linear.com/leadfree/

http://www.linear.com/tapeandreel/

8-Lead TSOT-23 8-Lead TSOT-23 8-Lead TSOT-23 8-Lead (3mm × 2mm) Plastic DFN 8-Lead (3mm × 2mm) Plastic DFN 8-Lead (3mm × 2mm) Plastic DFN

0°C to 70°C –40°C to 85°C –40°C to 125°C 0°C to 70°C –40°C to 85°C –40°C to 125°C

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LTC2915/LTC2916

ELECTRICAL CHARACTERISTICS

The l denotes the speciﬁ cations which apply over the full operating temperature range, otherwise speciﬁ cations are at T

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

CC(MIN)

CC(UVLO)

CC(SHUNT)

Monitor Input (VM)

MT120

MT50

MT33

MT25

MT18

MT15

MT12

MT10

MTADJ

VM(ADJ)

Three-State Inputs (SEL1, SEL2), (TOL, LTC2915)

TPIN,LOW

TPIN,HIGH

TPIN,Z

TPIN,H/L

Supply Voltage for Guaranteed RST Low RST Driven Low

Supply Undervoltage Lockout

Shunt Regulation Voltage I

VCC Pin Current SEL1, SEL2, TOL, MR = Open

12V, 5% Reset Threshold 12V, 10% Reset Threshold 12V, 15% Reset Threshold

5V, 5% Reset Threshold 5V, 10% Reset Threshold 5V, 15% Reset Threshold

3.3V, 5% Reset Threshold

3.3V, 10% Reset Threshold

3.3V, 15% Reset Threshold

2.5V, 5% Reset Threshold

2.5V, 10% Reset Threshold

2.5V, 15% Reset Threshold

1.8V, 5% Reset Threshold

1.8V, 10% Reset Threshold

1.8V, 15% Reset Threshold

1.5V, 5% Reset Threshold

1.5V, 10% Reset Threshold

1.5V, 15% Reset Threshold

1.2V, 5% Reset Threshold

1.2V, 10% Reset Threshold

1.2V, 15% Reset Threshold

1V, 5% Reset Threshold 1V, 10% Reset Threshold 1V, 15% Reset Threshold

ADJ (0.5V), 5% Reset Threshold ADJ (0.5V), 10% Reset Threshold ADJ (0.5V), 15% Reset Threshold

VM Input Impedance (Note 4) Fixed Threshold Modes

ADJ Input Current VM = 0.5V

Low Level Input Voltage

High Level Input Voltage

Pin Voltage when Open I

Allowable Leakage in Open State

Pin Input Current V

= 25°C. VCC = 2.5V, unless otherwise noted. (Note 2)

0.8 V

= 0.5mA

VCC

SEL1, SEL2, TOL = GND (LTC2915) MR = V

TPIN

(LTC2916)

= 0μA 0.9 V

= 0V, V

TPIN

5.7 6.2 7.0 V

l l

11.04

10.44

9.84

4.600

4.350

4.100

3.036

2.871

2.706

2.300

2.175

2.050

1.656

1.566

1.476

1.380

1.305

1.230

1.104

1.044

0.984

0.920

0.870

0.820

460.0

435.0

410.0

0.5 8

1.4 V

30 45

11.22

10.62

10.02

4.675

4.425

4.175

3.086

2.921

2.756

2.338

2.213

2.088

1.683

1.593

1.503

1.403

1.328

1.253

1.122

1.062

1.002

0.935

0.885

0.835

467.5

442.5

417.5

1.5 V

50 80

11.40

10.80

10.20

4.750

4.500

4.250

3.135

2.970

2.805

2.375

2.250

2.125

1.710

1.620

1.530

1.425

1.350

1.275

1.140

1.080

1.020

0.950

0.900

0.850

475.0

450.0

425.0

±15 nA

0.5 V

±5 μA

±20 μA

μA μA

mV mV mV

MΩ

V V V

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LTC2915/LTC2916

ELECTRICAL CHARACTERISTICS

The l denotes the speciﬁ cations which apply over the full operating temperature range, otherwise speciﬁ cations are at T

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Reset Timer Control (RT)

RT(UP)

RT(DOWN)

RT(INT)

RT(INT,LH)

Reset Output (RST)

RST(INT)

RST(EXT)

OH(RST)

Manual Reset Input (LTC2916)

RT Pull-Up Current VRT = 0.25V

RT Pull-Down Current VRT = 1.1V

Internal RT VCC Detect Current VRT = V

RT Internal Timer Threshold VRT Rising, Referenced to V

Internal Reset Timeout Period VRT = V

Adjustable Reset Timeout Period CRT = 2.2nF VM Undervoltage Detect to RST

Asserted Output Voltage Low RST VCC = 3.3V, I

RST Output Voltage High Leakage RST = V

Input Low Voltage

Input High Voltage

Pull Up Resistance

Pulsewidth

= 25°C. VCC = 2.5V, unless otherwise noted. (Note 2)

–2 –3 –4 μA

234 μA

VM Less Than Reset Threshold V

by More Than 5%

MTX

= 2.5mA = 1V, I = 0.8V, I

RST

= 100μA

RST

= 15μA

–100 –160 –300 mV

150 200 260 ms

16 20 25 ms

10 80 150 μs

l l l

0.8 • V

50 100 150

250 ns

18 μA

0.15

0.05

0.4

0.3

0.2

±1 μA

0.2 • V

kΩ

V V V

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.

TIMING DIAGRAM

Monitor Input Timing

MTx

RST

Note 3: VCC maximum pin voltage is limited by input current. Since the V

pin has an internal 6.2V shunt regulator, a low impedance supply

which exceeds 5.7V may exceed the rated terminal current. Operation from higher voltage supplies requires a series dropping resistor. See Applications Information.

Note 4: Input impedance is dependent on the conﬁ guration of the SEL pins.

RST

29156 TD01

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TYPICAL PERFORMANCE CHARACTERISTICS

LTC2915/LTC2916

= 25°C unless otherwise noted.

Threshold Voltage vs Temperature

1.5

1.0

(%)

0.5

MTnn

–0.5

NORMALIZED V

–1.0

–1.5

–50

–25 0

TEMPERATURE (°C)

MT25

50 100 125

25 75

Internal Reset Timeout Period vs Temperature

250

RT = V

230

RST(INT)

210

MTADJ

MT120

29156 G01

Quiescent Supply Current vs Temperature

SEL1 = 0V SEL2 = 2.5V

(μA)

TOL = OPEN

VCC = 5.5V

QUIESCENT SUPPLY CURRENT, I

–50

–25 0 25 50

VCC = 2.5V

VCC = 1.5V

TEMPERATURE (°C)

Shunt Regulation Voltage vs Temperature

6.4

(V)

CC(SHUNT)

6.3

ICC = 5mA

ICC = 1mA

75 100 125

29156 G02

Allowable Glitch Duration vs Magnitude

300

250

200

150

100

MAXIMUM ALLOWABLE GLITCH DURATION (μs)

0.1 GLITCH PERCENTAGE PAST THRESHOLD (%)

RESET OCCURS ABOVE CURVE

1 10 100

Shunt Regulation Voltage vs Supply Current

7.0

(V)

6.8

CC(SHUNT)

6.6

29156 G03

190

170

RESET TIMEOUT PERIOD (ms), t

150

–50 –25

TEMPERATURE (°C)

RST Output Voltage vs V

100k PULL-UP TO V SEL1 = SEL2 = TOL = 0V

= 0.5V

RST VOLTAGE (V)

1234

SUPPLY VOLTAGE, VCC (V)

6.2

SHUNT REGULATION VOLTAGE, V

6.1

100

125

29156 G04

29156 G07

–50

RST Pull-Down Current vs V

(mA)

RST

PULL-DOWN CURRENT, I

ICC = 100μA

–25 0 25 50

TEMPERATURE (°C)

1234

SUPPLY VOLTAGE, VCC (V)

75 100 125

RST AT 150mV

RST AT 50mV

29156 G05

29156 G08

6.4

6.2

SHUNT REGULATION VOLTAGE, V

6.0

0.01

RST VOL vs I

1.0 NO PULL-UP R

0.8

0.6

0.4

RST VOLTAGE (V)

0.2

0.1

SUPPLY CURRENT, ICC (mA)

= 2.5V

RST

TA = 25°C

RST

(mA)

TA = 125°C

TA = –40°C

100

29156 G06

29156 G09

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LTC2915/LTC2916

PIN FUNCTIONS

(TSOT/DFN)

GND (Pin 4/Pin 1): Device Ground.

MR (Pin 3/Pin 2) (LTC2916 only): Manual Reset Input (Active Low). A low level on the MR input causes the part to issue a reset, which is released one reset timeout after the input goes high. The pin has an internal 100k pull-up

, and thus may interface directly to a momentary

to V

pushbutton. Leave open if unused. RST (Pin 5/Pin 8): Open Drain RST Output. Asserts low

when VM is below the threshold selected by SEL1, SEL2 and TOL input pins. Held low for an adjustable timeout after VM input is above threshold.

RT (Pin 6/Pin 7): Reset Timeout Control Pin. Attach an external Capacitor (C

) to GND to set a reset timeout of

9ms/nF. Floating RT generates a reset timeout of approximately 400μs. Tie RT to V

to generate a reset timeout

of approximately 200ms. SEL1, SEL2 (Pins 2, 7/Pins 3, 6): Monitor Voltage Select

Three-State Inputs. SEL1 and SEL2 control the nominal threshold voltage that VM is set to monitor. Connect to V

GND or leave unconnected in open state. (See Table 1).

TOL (Pin 3/Pin 2) (LTC2915 only): Three-State Input for Supply Tolerance Selection (–5%, –10% or –15%). Controls the tolerance band at which the VM supply is monitored. Connect to V

, GND, or leave unconnected

in open state. (See Table 2).

(Pin 8/Pin 5): Power Supply Input. Bypass this pin

to ground with a 0.1μF ceramic capacitor. A minimum of

1.5V on V

ensures that the part is out of under voltage

lockout and that the voltage thresholds are accurate. Operates as a direct supply input for voltages up to 5.5V. Operates as a shunt regulator for supply voltages greater than 5.7V and should have a resistor between this pin and the supply to limit V

input current to no greater than

5mA. When used without a current-limiting resistor, pin voltage must not exceed 5.7V.

VM (Pin 1/Pin 4): Voltage Monitor Input to RST Compara- tor. SEL1, SEL2 and TOL inputs select the exact threshold that asserts the RST output.

Exposed Pad (Pin 9, DFN Only): Exposed Pad may be left open or connected to device ground.

BLOCK DIAGRAM

SEL1 MRSEL2

3 STATE DECODE

0.5V

–

MONITOR

DIVIDER MATRIX

REFERENCE

DIVIDER MATRIX

TOL

LTC2916LTC2915

DETECT

100k

– +

INTERNAL

200ms TIMER

ADJUSTABLE

RESET TIMER

RESET

DRIVER LOGIC

6.2V

RST

GND

29156 BD

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APPLICATIONS INFORMATION

LTC2915/LTC2916

Supply Monitoring

The LTC2915/LTC2916 are low voltage single supply monitors with selectable thresholds. Two three-state inputs select one of nine internally programmed thresholds. For the LTC2915, a third three-state input selects the tolerance at which the supply connected to the VM

pin is monitored (–5%, –10%, –15%). The tolerance for the LTC2916 is ﬁ xed at –5%. Threshold accuracy is guaranteed at ±1.5% over the entire operating temperature range.

The LTC2915/LTC2916 asserts the RST output low when

is below the programmed threshold, and for a reset

VM timeout (t

) after VM goes above the threshold. The reset

RST

timeout can be conﬁ gured to use an internal timer with no external components, or an adjusted timer programmed by placing an external capacitor from RT to ground.

Power-Up

powers the drive circuits for the RST pin. Therefore,

as soon as V

reaches 0.8V during power up, the RST

output asserts low.

Until V

reaches the undervoltage lockout threshold

(guaranteed less than 1.5V), RST is held low regardless of the state of VM.

Once V and VM timer is started. After the reset timeout (t

is above the under voltage lockout threshold

is above the programmed threshold, the reset

), the open

RST

drain pull-down releases RST and the external pull-up resistor pulls high.

Power-Down

On power-down, once VM

drops below the undervoltage lockout, RST asserts

drops below its threshold or

logic low.

Monitor Threshold Control

The monitor threshold on the VM

pin is controlled by the SEL1, SEL2 and TOL three-state pins. The SEL1 and SEL2 pins select one of nine preset nominal voltages (including one externally adjustable threshold) as shown in Table 1.

The SEL1 and SEL2 three-state input pins should be connected to GND, V

or left unconnected during normal

operation. Note that when left unconnected, the maximum leakage allowable from the pin to either GND or V

±5μA.

The tolerance at which the monitored supply is measured is set by the TOL pin (LTC2915 only), as shown in Table 2. If desired (e.g. for margining purposes), the TOL pin may be driven by a three-state buffer. That three-state buffer must have a V

and VOH which meet the VIL and VIH of

the TOL pin speciﬁ ed in the Electrical Characteristics, and maintain less than 5μA of leakage in the open state.

Threshold Accuracy

The trip threshold for VM is selected by conﬁ guring the three-state input pins. When using the adjustable input, an external resistive divider sets the trip threshold, allowing the user complete control over the trip point. Selection of this trip voltage is crucial to the reliability of the system.

Table 1. Voltage Threshold Settings

NOMINAL VOLTAGE SEL1 SEL2

Open

GND

12V V

5V V

3.3V V

2.5V Open V

1.8V Open Open

1.5V* Open GND

1.2V* GND V

1V* GND Open

ADJ* (0.5V) GND GND

*Require a separate supply for V

Table 2. System Voltage Tolerance Settings

TOLERANCE TOL

–5% V

–10% Open

–15% GND

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LTC2915/LTC2916

APPLICATIONS INFORMATION

Any power supply has some tolerance band within which it is expected to operate (e.g. 5V±10%). It is generally undesirable that a supervisor issue a reset when the power supply is inside this tolerance band. Such a “nuisance” reset reduces reliability by preventing the system from functioning under normal conditions.

To prevent nuisance resets, the supervisor threshold must be guaranteed to lie outside the power supply tolerance band. To ensure that the threshold lies outside the power supply tolerance range, the nominal threshold must lie outside that range by the monitor’s accuracy speciﬁ cation.

All 27 of the selectable thresholds have the same relative threshold accuracy of ±1.5% of the programmed nominal input voltage (over the full operating temperature range). Consider the example of monitoring a 5V supply with a 10% tolerance. The nominal threshold internal to the LTC2915 is 11.5% below the 5V input at 4.425V. With ±1.5% accuracy, the trip threshold range is 4.425V±75mV over temperature (i.e. 10% to 13% below 5.0V). The monitored system must thus operate reliably down to 4.35V or 13% below 5.0V over temperature.

Glitch Immunity

The above discussion is concerned only with the DC value of the monitored supply. Real supplies also have relatively high-frequency variation, from sources such as load transients, noise, and pickup. These variations should not be considered by the monitor in determining whether a supply voltage is valid or not. The variations may cause spurious outputs at RST, particularly if the supply voltage is near its trip threshold.

Two techniques are used to combat spurious reset without sacriﬁ cing threshold accuracy. First, the timeout period helps prevent high-frequency variation whose frequency is above 1/ t

from appearing at the RST output.

RST

period, the timer resets and begins again when the supply next becomes valid.

While the reset timeout is useful at preventing toggling of the reset output in most cases, it is not effective at preventing nuisance resets due to short glitches (due to load transients or other effects) on a valid supply.

To reduce sensitivity to these short glitches, the comparator has additional anti-glitch circuitry. Any transient at the input of the comparator needs to be of sufﬁ cient magnitude and duration t

before it can change the monitor state.

The combination of the reset timeout and anti-glitch circuitry prevents spurious changes in output state without sacriﬁ cing threshold accuracy.

Adjustable Input

When the monitor threshold is conﬁ gured as ADJ, the internal comparator input is connected to the pin without a resistive divider, and the pin is high-impedance. Thus, any desired threshold may be chosen by attaching VM

to a tap point on an external resistive divider between the monitored supply and ground, as shown in Figure 1.

The reference input of the comparator is controlled by the tolerance pin. The external resistive divider should make the voltage at VM = 0.5V when the supply is at nominal value. The actual threshold of VM accounts for the supply tolerance of ±1.5% guaranteed over the full operating temperature range. The resulting tolerances are –6.5%, –11.5%, –16.5% which correspond to 0.468V, 0.443V,

0.418V repectively.

MON

–

When the voltage at VM

goes below the threshold, the

RST pin asserts low. When the supply recovers past the threshold, the reset timer starts (assuming it is not disabled), and RST does not go high until it ﬁ nishes. If the supply becomes invalid any time during the timeout

0.5V

–

29156 F01

Figure 1. Setting the Trip Point Using the Adjustable Threshold

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APPLICATIONS INFORMATION

LTC2915/LTC2916

Typically, the user will pick a value of R1 based on acceptable current draw. Current used by the resistor divider will be approximately

⎛

105=

⎜

⎝

⎞ ⎟

⎠

Recommended range of R1 is 1k to 1M. Higher values of resistance exacerbate the degradation of threshold accuracy due to leakage currents.

If the nominal value of the supply being monitored is

, then

NOM

R2 = R1(2V

NOM

– 1)

Resistor tolerances must be taken into account when determining the overall accuracy.

Selecting the Reset Timing Capacitor

The reset timeout period can be set to one of two ﬁ xed internal timers or set with a capacitor in order to accommodate a variety of applications. Connecting a capacitor,

, between the RT pin and ground sets the reset timeout

period, t

. The following formula approximates the value

RST

of capacitor needed for a particular timeout:

= t

• 110 [pF/ms]

RST

For example, using a standard capacitor value of 2.2nF would give 20ms delay.

Leaving RT open with no external capacitor generates a reset timeout of approximately 400μs. Shorting RT to V

generates a reset timeout of approximately 200ms.

RST Output Characteristics

The DC characteristics of the RST pull-down strength are shown in the Typical Performance Characteristics section. RST is an open-drain pin and thus requires an external pull-up resistor to the logic supply. RST may be pulled above V

, providing the voltage limits of the pin

are observed. The open-drain of the RST pin allows for wired-OR con-

nection of several LTC2915/LTC2916s.

As noted in the discussion of power up and power down, the circuits that drive RST are powered by V fault condition, V

of at least 1V ensures that RST pulls

. During a

low.

Manual Reset (LTC2916 Only)

The LTC2916 includes the MR pin for applications where a manual reset is desired. MR is internally pulled up, allowing it to interface with a push button with no external components required. Asserting MR low when RST is high, initiates a reset, resulting in RST being asserted low for the set reset timeout.

Shunt Regulator

Figure 2 shows the reset timeout period as a function of the value of the timer capacitor.

10000

1000

(ms)

RST

100

RESET TIMEOUT PERIOD, t

0.1

0.001

Figure 2. Reset Timeout Period vs RT Capacitance

0.10.01 1 10 100 1000

RT PIN CAPACITANCE, CRT (nF)

29156 F02

The LTC2915 and LTC2916 contain an internal 6.2V shunt regulator on the V

pin to allow operation from a high

voltage supply. To operate the part from a supply higher than 5.7V, the V

pin must have a series resistor, RCC, to

the supply. This resistor should be sized according to the following equation:

SMAX

where V

S(MIN)

.−

≤≤

and V

are the operating minimum

S(MAX)

−57

250μ

SMIN() ()

and maximum of the supply.

As an example, consider operation from an automobile battery which might dip as low as 10V or spike to 60V. We must then pick a resistance between 10.86k and 12k.

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LTC2915/LTC2916

TYPICAL APPLICATIONS

12V Supply Monitor Powered from 12V, Utilizing

Internal Shunt Regulator with 3.3V Logic Out

12V 3.3V

11k

BYPASS

LTC2915 μP

SEL1 GND

SEL2

TOL

GND RT

RST RST

0.1μF

R 10k

29156 TA02

5V, –10% Tolerance Supply Monitor with

200ms Internal Reset Timeout

3.3V

LTC2915

SEL1

SEL2

TOL

GND RT

3.3V

RST

BYPASS

0.1μF

R 10k

RST

μP

GND

29156 TA03

9V, –15% Tolerance Supply Monitor with 3.3V Logic Out 1V, –15% Tolerance Supply Monitor with 90ms Timeout

R2 866k

51.1k

3.3V

LTC2915

SEL1

SEL2

TOL

GND RT

BYPASS

0.1μF

RST

R 10k

μP

RST

GND

29156 TA04

3.3V

LTC2915

SEL1

SEL2

TOL

GND RT

BYPASS

0.1μF

RST

0.01μF

R 10k

μP

RST

GND

29156 TA05

1.8V, –5% Supply Monitor with Manual Reset

1.8V

MANUAL RESET

PUSHBUTTON

*OPTIONAL RESISTOR RECOMMENDED TO EXTEND ESD TOLERANCE

10k*

BYPASS

0.1μF

LTC2916 μP

SEL1 GND

SEL2

GND RT

RST RST

R 10k

1.5V Supply Monitor with Tolerance Control for Margining, –5% Operation with –15% Margining

3.3V

LTC2915

29156 TA07

1.5V

SEL1

SEL2

GND RT

BYPASS

0.1μF

RST

10k

μP

RST I/O

–5%–15%

GND

29156 TA08

29156fa

PACKAGE DESCRIPTION

LTC2915/LTC2916

TS8 Package

8-Lead Plastic TSOT-23

(Reference LTC DWG # 05-08-1637)

0.52 MAX

3.85 MAX

2.62 REF

RECOMMENDED SOLDER PAD LAYOUT

PER IPC CALCULATOR

0.20 BSC

DATUM ‘A’

NOTE:

1. DIMENSIONS ARE IN MILLIMETERS

2. DRAWING NOT TO SCALE

3. DIMENSIONS ARE INCLUSIVE OF PLATING

4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR

5. MOLD FLASH SHALL NOT EXCEED 0.254mm

6. JEDEC PACKAGE REFERENCE IS MO-193

0.65 REF

0.30 – 0.50 REF

1.22 REF

1.4 MIN

2.80 BSC

0.09 – 0.20 (NOTE 3)

1.50 – 1.75 (NOTE 4)

1.00 MAX

0.65 BSC

0.80 – 0.90

2.90 BSC (NOTE 4)

PIN ONE ID

1.95 BSC

0.22 – 0.36 8 PLCS (NOTE 3)

0.01 – 0.10

TS8 TSOT-23 0802

DDB Package

8-Lead Plastic DFN (3mm × 2mm)

(Reference LTC DWG # 05-08-1702 Rev B)

0.61 ±0.05

(2 SIDES)

0.70 ±0.05

2.55 ±0.05

1.15 ±0.05

PACKAGE

0.25 ± 0.05

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

NOTE:

1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229

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

2.20 ±0.05

(2 SIDES)

0.50 BSC

OUTLINE

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.

PIN 1 BAR

TOP MARK

(SEE NOTE 6)

0.200 REF

3.00 ±0.10

(2 SIDES)

2.00 ±0.10

(2 SIDES)

0.75 ±0.05

R = 0.05

0 – 0.05

R = 0.115

TYP

0.56 ± 0.05

(2 SIDES)

TYP

0.25 ± 0.05

BOTTOM VIEW—EXPOSED PAD

2.15 ±0.05

(2 SIDES)

0.40 ± 0.10

0.50 BSC

PIN 1 R = 0.20 OR

0.25 × 45° CHAMFER

(DDB8) DFN 0905 REV B

29156fa

LTC2915/LTC2916

TYPICAL APPLICATION

Dual Supply Monitor (1.8V and 12V) with Manual Reset and 200ms Reset Timeout

1.8V

MANUAL RESET

PUSHBUTTON

BYPASS

0.1μF

LTC2916

SEL1

SEL2 MR

GND RT

10k

RST

1.8V

12V

1.8V

LTC2915 μP

SEL1 GND

SEL2

TOL

GND

RST RST

1.8V

29156 TA10

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PART NUMBER DESCRIPTION COMMENTS

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LTC2900 Programmable Quad Supply Monitor 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

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LTC2907 Precision Dual Supply Monitor 1 Selectable and 1 Adjustable Separate V

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LTC2909 Precision Triple/Dual Input UV, OV Monitor 2 ADJ Inputs, Monitors Negative Voltages

LTC2910 Octal Positive/Negative Voltage Monitor

LTC2912 Single UV/OV Voltage Monitor, Adjustable UV and OV Trip

Values

LTC2913 Dual UV/OV Voltage Monitor

LTC2914 Qual UV/OV Positive/Negative Voltage Monitor

Adjustable RESET, 10-Lead MSOP and 3mm × 3mm 10-Lead DFN

Pin, RST/RST Outputs

Pin, Adjustable Reset Timer

16-Lead SSOP and 5mm × 3mm DFN Packages 8-Lead TSOT and 3mm × 2mm DFN Packages

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Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507

●

www.linear.com

29156fa

LT 0108 REV A • PRINTED IN USA

LINEAR TECHNOLOGY LTC2915, LTC2916 Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual