Linear Technology LTC2902-2IGN, LTC2902-2CGN, LTC2902-1IGN, LTC2902-1CGN Datasheet

Monitor with Adjustable Reset Timer

FEATURES

■

Simultaneously Monitors Four Supplies

■

16 User Selectable Combinations of 5V, 3.3V, 3V,

2.5V, 1.8V, 1.5V and/or ±Adjustable Voltage
Thresholds

■

Guaranteed Threshold Accuracy: ±1.5% of Monitored
Voltage Over Temperature

■

Selectable Supply Tolerance: 5%, 7.5%,
10%, 12.5% Below Monitored Voltage

■

Low Supply Current: 43µA Typ

■

Adjustable Reset Time

■

RESET Disable Pin for Margining Applications

■

Open-Drain RST Output (LTC2902-1)

■

Push-Pull RST Output (LTC2902-2)

■

Individual Nondelayed Monitor Outputs for Each Supply

■

Power Supply Glitch Immunity

■

Guaranteed RESET for VCC ≥ 1V

U

APPLICATIO S

■

Desktop and Notebook Computers

■

Multivoltage Systems

■

Telecom Equipment

■

Portable Battery-Powered Equipment

■

Network Servers

LTC2902

Programmable Quad Supply

and Supply Tolerance

U

DESCRIPTIO

The LTC®2902 is a programmable supply monitor for sys­tems with up to four supply voltages. One of 16 preset or
adjustable voltage monitor combinations can be selected
using an external resistor divider connected to the pro­gram pin. The preset voltage thresholds are digitally pro­grammable to 5%, 7.5%, 10% or 12.5% below the nomi­nal operating voltage, and are accurate to 1.5% over tem­perature. All four voltage comparator outputs are con­nected to separate pins for individual supply monitoring.

The reset delay time is adjustable using an external
capacitor. Tight voltage threshold accuracy and glitch
immunity ensure reliable reset operation without false
triggering. The RST output is guaranteed to be in the
correct state for VCC down to 1V and may be disabled
during supply margin testing. The LTC2902-1 features
an open-drain RST output, while the LTC2902-2 has a
push-pull RST output.

The 43µA supply current makes the LTC2902 ideal for power
conscious systems and the part may be configured to
monitor less than four inputs. The LTC2902-1/LTC2902-2
are available in the 16-lead narrow SSOP package.

, LTC and LT are registered trademarks of Linear Technology Corporation.

TYPICAL APPLICATIO

Quad Supply Monitor with Adjustable Tolerance (5V, 3.3V, 2.5V, 1.8V)

CONVERTER

DC/DC

U

0.1µF

5V

3.3V

2.5V

1.8V

C1

C2

0.1µF

59k
1%

40.2k
1%

SYSTEM

LOGIC

133

LTC2902-2

GND

10

V4V3

CRT

COMP1
COMP2
COMP3
COMP4

5

4

V1

14

V2

12

V

REF

R1

11

V

R2

PG

RST

RDIS

C
47nF

T0
T1

RT

R3
10k

2
16
1
15
6

8

7

TOLERANCE = 5%

9

2902 TA01

POWER

GOOD

MARGIN

t

RST

= 216ms

2902f

1

LTC2902

PACKAGE/ORDER I FOR ATIO

UU

W

GN PACKAGE

16-LEAD PLASTIC SSOP

1
2
3
4
5
6
7
8

TOP VIEW

16
15
14
13
12
11
10

9

COMP3
COMP1

V3

V1
CRT
RST

T0

RDIS

COMP2
COMP4
V2
V4
V

REF

V

PG

GND
T1

WWWU

ABSOLUTE AXI U RATI GS

(Notes 1, 2, 3)

V1, V2, V3, V4, VPG..................................... –0.3V to 7V

RST (LTC2902-1)........................................ –0.3V to 7V

RST (LTC2902-2).......................... –0.3V to (V2 + 0.3V)

COMPX, RDIS ............................................. – 0.3V to 7V

T0, T1 .......................................... –0.3V to (VCC + 0.3V)

CRT ............................................. –0.3V to (VCC + 0.3V)

V

............................................. – 0.3V to (VCC + 0.3V)

REF

Reference Load Current (I

V4 Input Current (–ADJ Mode) ............................ –1mA

Operating Temperature Range

LTC2902-1C/LTC2902-2C ....................... 0°C to 70°C

LTC2902-1I/LTC2902-2I .................... –40°C to 85°C

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

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

) ............................ ±1mA

VREF

ORDER PART

NUMBER

LTC2902-1CGN
LTC2902-2CGN
LTC2902-1IGN
LTC2902-2IGN

GN16 PART MARKING

29021
29022

T

= 125°C, θJA = 130°C/W

JMAX

Consult LTC Marketing for parts specified with wider operating temperature ranges.

29021I
29022I

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise noted. (Note 3)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

RT50

V

RT33

V

RT30

V

RT25

V

RT18

V

RT15

V

RTA

2

5V, 5% Reset Threshold V1 Input Threshold ● 4.600 4.675 4.750 V
5V, 7.5% Reset Threshold
5V, 10% Reset Threshold
5V, 12.5% Reset Threshold

3.3V, 5% Reset Threshold V1, V2 Input Threshold ● 3.036 3.086 3.135 V

3.3V, 7.5% Reset Threshold

3.3V, 10% Reset Threshold

3.3V, 12.5% Reset Threshold
3V, 5% Reset Threshold V2 Input Threshold ● 2.760 2.805 2.850 V

3V, 7.5% Reset Threshold
3V, 10% Reset Threshold
3V, 12.5% Reset Threshold

2.5V, 5% Reset Threshold V2, V3 Input Threshold ● 2.300 2.338 2.375 V

2.5V, 7.5% Reset Threshold

2.5V, 10% Reset Threshold

2.5V, 12.5% Reset Threshold

1.8V, 5% Reset Threshold V3, V4 Input Threshold ● 1.656 1.683 1.710 V

1.8V, 7.5% Reset Threshold

1.8V, 10% Reset Threshold

1.8V, 12.5% Reset Threshold

1.5V, 5% Reset Threshold V3, V4 Input Threshold ● 1.380 1.403 1.425 V

1.5V, 7.5% Reset Threshold

1.5V, 10% Reset Threshold

1.5V, 12.5% Reset Threshold
ADJ, 5% Reset Threshold V3, V4 Input Threshold ● 0.492 0.500 0.508 V

ADJ, 7.5% Reset Threshold
ADJ, 10% Reset Threshold
ADJ, 12.5% Reset Threshold

The ● denotes the specifications which apply over the full operating

● 4.475 4.550 4.625 V

● 4.350 4.425 4.500 V

● 4.225 4.300 4.375 V

● 2.954 3.003 3.053 V

● 2.871 2.921 2.970 V

● 2.789 2.838 2.888 V

● 2.685 2.730 2.775 V

● 2.610 2.655 2.700 V

● 2.535 2.580 2.625 V

● 2.238 2.275 2.313 V

● 2.175 2.213 2.250 V

● 2.113 2.150 2.188 V

● 1.611 1.638 1.665 V

● 1.566 1.593 1.620 V

● 1.521 1.548 1.575 V

● 1.343 1.365 1.388 V

● 1.305 1.328 1.350 V

● 1.268 1.290 1.313 V

● 0.479 0.487 0.494 V

● 0.466 0.473 0.481 V

● 0.453 0.460 0.467 V

2902f

LTC2902

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise noted. (Note 3)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

RTAN

V

CC

V

CCMINP

V

CCMINC

V

REF

V

PG

I

VPG

I

V1

I

V2

I

V3

I

V4

I

CRT(UP)

I

CRT(DN)

t

RST

t

UV

V

OL

V

OH

V

OH

Digital Inputs T0, T1, RDIS

V

IL

V

IH

I

INTOL

V

IL

V

IH

I

RDIS

Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.

Note 2: All voltage values are with respect to GND.
Note 3: The greater of V1, V2 is the internal supply voltage (V
Note 4: Under static no-fault conditions, V1 will necessarily supply quiescent

current. If at any time V2 is larger than V1, V2 must be capable of supplying
the quiescent current, programming (transient) current and reference load
current.

–ADJ Reset Threshold V4 Input Threshold ● –18 0 18 mV
Minimum Internal Operating Voltage RST, COMPX in Correct Logic State; ● 1V

VCC Rising Prior to Program
Minimum Required for Programming VCC Rising ● 2.42 V
Minimum Required for Comparators VCC Falling ● 2.32 V
Reference Voltage VCC ≥ 2.3V, I

= ±1mA, C

VREF

≤ 1000pF

REF

T0 Low, T1 Low ● 1.192 1.210 1.228 V

T0 Low, T1 High

● 1.160 1.178 1.195 V

T0 High, T1 Low ● 1.128 1.146 1.163 V

T0 High, T1 High
Programming Voltage Range VCC ≥ V
VPG Input Current VPG = V

CCMINP

REF

V1 Input Current V1 = 5V, I

= 12µA, (Note 4) ● 43 75 µA

VREF

● 1.096 1.113 1.130 V

● 0V

● ±20 nA

REF

V2 Input Current V2 = 3.3V ● 0.8 2 µA
V3 Input Current V3 = 2.5V ● 0.52 1.2 µA

V3 = 0.55V (ADJ Mode) –15 15 nA
V4 Input Current V4 = 1.8V ● 0.34 0.8 µA

V4 = 0.55V (ADJ Mode)

● –15 15 nA

V4 = –0.05V (–ADJ Mode) ● –15 15 nA
CRT Pull-Up Current V
CRT Pull-Down Current V

= 0V ● –1.4 –2 –2.6 µA

CRT

= 1.3V ● 10 20 30 µA

CRT

Reset Time-Out Period CRT = 1500pF ● 579 ms
VX Undervoltage Detect to RST or COMPX VX Less Than Reset Threshold V

RTX

150 µs

by More Than 1%
Output Voltage Low RST, COMPX I

= 2.5mA; V1 = 3V, V2 = 3V; ● 0.15 0.4 V

SINK

V3, V4 = 0V; VPG = 0V

I

= 100µA; V2 = 1V; V1, V3, V4 = 0V ● 0.05 0.3 V

SINK

I

= 100µA; V1 = 1V; V2, V3, V4 = 0V ● 0.05 0.3 V

SINK

Output Voltage High RST, COMPX (Note 5) I
Output Voltage High RST (LTC2902-2) I

= 1µA ● V2 – 1 V

SOURCE

= 200µA ● 0.8 • V2 V

SOURCE

(Note 6)

T0, T1 Low Level Input Voltage VCC = 3.3V to 5.5V ● 0.3V
T0, T1 High Level Input Voltage VCC = 3.3V to 5.5V ● 0.7V
T0, T1 Input Current T0 = 0V, T1 = V

CC

● ±0.1 ±1 µA

CC

CC

RDIS Input Threshold Low VCC = 3.3V to 5.5V ● 0.4 V
RDIS Input Threshold High VCC = 3.3V to 5.5V ● 1.6 V
RDIS Pull-Up Current V

= 0V –10 µA

RDIS

Note 5: The output pins RST and COMPX have internal pull-ups to V2 of
typically 6µA. However, external pull-up resistors may be used when faster

CC

rise times are required or for V

).

Note 6: The push-pull RST output pin on the LTC2902-2 is
to V2.

voltages greater than V2.

OH

actively

pulled up

2902f

V

V
V

3

LTC2902

TEST CIRCUITS

V1
V2
V3
V4

LTC2902-1

2902 F01

RST
OR COMPX

I

SOURCE

1µA

V1
V2
V3
V4

LTC2902-1

2902 F02

RST
OR COMPX

I

SINK

2.5mA,
100µA

V1
V2
V3
V4

LTC2902-2

2902 F03

RST

I

SOURCE

200µA

Figure 1. RST, COMPX VOH Test Figure 2. RST, COMPX VOL Test Figure 3. Active Pull-Up RST VOH Test

UWW

TI I G DIAGRA

VX Monitor Timing

V

RTX

t

t

UV

RST

1.5V

2902 TD

RST

COMPX

V

X

UW

TYPICAL PERFOR A CE CHARACTERISTICS

5V Threshold Voltage
vs Temperature

4.75

4.70

(V)

4.65

RT50

4.60

4.55

4.50

4.45

4.40

4.35

THRESHOLD VOLTAGE, V

4.30

4.25
–60

–20

–40 0

TEMPERATURE (°C)

5%

7.5%

10%

12.5%

20

40

80

60

100

2902 G01

3.3V Threshold Voltage
vs Temperature

3.135

3.100

3.065

(V)

RT33

3.030

2.995

2.960

2.925

2.890

2.855

THRESHOLD VOLTAGE, V

2.820

2.785
–60

–20

–40 0

TEMPERATURE (°C)

5%

7.5%

10%

12.5%

20

60

40

4

80

2902 G02

100

3V Threshold Voltage
vs Temperature

2.850

2.815

(V)

2.780

RT30

2.745

2.710

2.675

2.640

2.605

THRESHOLD VOLTAGE, V

2.570

2.535
–60

–20

–40 0

TEMPERATURE (°C)

5%

7.5%

10%

12.5%

20

40

80

60

100

2902 G03

2902f

UW

TYPICAL PERFOR A CE CHARACTERISTICS

LTC2902

2.5V Threshold Voltage
vs Temperature

2.375

2.350

2.325

(V)

2.300

RT25

2.275

2.250

2.225

2.200

2.175

2.150

THRESHOLD VOLTAGE, V

2.125

2.100
–60

–20

–40 0

TEMPERATURE (°C)

ADJ Threshold Voltage
vs Temperature

0.508

0.503

0.498

(V)

0.493

RTA

0.488

0.483

0.478

0.473

0.468

0.463

THRESHOLD VOLTAGE, V

0.458

0.453
–60

–20

–40 0

TEMPERATURE (°C)

5%

7.5%

10%

12.5%

5%

7.5%

10%

12.5%

1.8V Threshold Voltage
vs Temperature

1.710

1.685

(V)

1.660

RT18

1.635

1.610

1.585

1.560

THRESHOLD VOLTAGE, V

1.535

100

1.510
–60

–40 0

20

40

80

60

2902 G04

5%

7.5%

10%

12.5%

–20

20

TEMPERATURE (°C)

40

100

2902 G05

80

60

1.5V Threshold Voltage
vs Temperature

1.425

1.405

(V)

1.385

RT15

1.365

1.345

1.325

1.305

THRESHOLD VOLTAGE, V

1.285

1.265
–60

–20

–40 0

TEMPERATURE (°C)

5%

7.5%

10%

12.5%

20

40

80

60

100

2902 G06

–ADJ Threshold Voltage
vs Temperature

0.018

0.012

(V)

RTAN

0.006

0

–0.006

–0.012

THRESHOLD VOLTAGE, V

100

–0.018

–60

–40 0

–20

20

TEMPERATURE (°C)

40

100

2902 G08

80

60

20

40

80

60

2902 G07

1.228

1.216

1.204

1.192

1.180

1.168

(V)

REF

1.156

V

1.144

1.132

1.112

1.108

1.096

V

vs Temperature

REF

–60

–20

–40 0

5%

7.5%

10%

12.5%

20

TEMPERATURE (°C)

40

80

60

100

2902 G09

IV1 vs Temperature

100

V1 = 5V

90

V2 = 3.3V
V3 = 2.5V

80

V4 = 1.8V

70
60
50

(µA)

V1

I

40
30
20
10

0

–60

–40 0

–20

20

TEMPERATURE (°C)

40

IV2 vs Temperature

1.5
V1 = 5V

1.4

V2 = 3.3V
V3 = 2.5V

1.3
V4 = 1.8V

1.2

1.1

1.0

(µA)

V2

I

0.9

0.8

0.7

0.6

80

60

100

2902 G10

0.5

–60

–40 0

–20

TEMPERATURE (°C)

80

20

60

40

100

2902 G11

IV3 vs Temperature

1.1
V1 = 5V

1.0

V2 = 3.3V
V3 = 2.5V

0.9
V4 = 1.8V

0.8

0.7

0.6

(µA)

V3

I

0.5

0.4

0.3

0.2

0.1

–60

–40 0

–20

20

TEMPERATURE (°C)

40

80

60

100

2902 G12

2902f

5