Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - system monitor Dual voltage detector TSOT 23 6

LTC2903-1

29031f a

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Multivoltage Systems

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Optical Networking Systems

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Cell Phone Base Stations

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Network Servers

Precision Quad Supply

Monitor in 6-Lead SOT-23

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

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Ultralow Voltage Reset: V

= 0.5V Guaranteed

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Monitor Four Inputs Simultaneously

3.3V, 2.5V, 1.8V, ADJ (LTC2903-A1)

5V, 3.3V, 2.5V, 1.8V (LTC2903-B1)

5V, 3.3V, 1.8V, –5.2V (LTC2903-C1)

3.3V, ADJ, ADJ, ADJ (LTC2903-D1)

5V, ADJ, ADJ, ADJ (LTC2903-E1)

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Guaranteed Threshold Accuracy: ±1.5% of

Monitored Voltage over Temperature

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10% (A1, B1, C1) and 5% (D1, E1) Undervoltage

Monitoring

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Low Supply Current: 20µA Typical

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200ms Reset Time Delay

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Active Low Open-Drain RST Output

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Power Supply Glitch Immunity

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Low Profile (1mm) SOT-23 (ThinSOT

) Package

The LTC

2903-1 monitors up to four supply voltages. The

common reset output remains low until all four inputs

have been in compliance for 200ms. Voltage thresholds

maintain ±1.5% accuracy over temperature (with respect

to the monitored voltage). The LTC2903-1 features an

open-drain RST output with a weak internal pullup.

Internal supply voltage (V

) is generated from the greater

voltage on the V1, V2 inputs. V

= V1 for LTC2903-D1 and

LTC2903-E1. The RST output is guaranteed to sink at least

5µA (V

= 0.15V) for V

down to 0.5V and will typically

conduct current down to 0V. Quiescent current is 20µA

typical, making the LTC2903-1 ideal for power conscious

systems. The LTC2903-1 is available in a 6-lead low profile

(1mm) SOT-23 package.

ThinSOT is a trademark of Linear Technology Corporation.

, INPUT SUPPLY VOLTAGE (V)

RESET PIN VOLTAGE (V)

0.06

0.08

0.10

0.8

2903 TA01b

0.04

0.02

0.05

0.07

0.09

0.03

0.01

0.20.1

1µA

0.40.3

0.6 0.7 0.9

0.5

2µA

5µA

20µA

= V1 = V2 = V3

LTC2903-B1

10µA

Low Voltage Reset Pull-Down Performance

vs External Pull-Up Current and Input Supply Voltage

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

GND

RST

LTC2903-B1

0.1µF

1.8V

0.1µF

2903 TA01

2.5V

3.3V

DC/DC

CONVERTER

SYSTEM

LOGIC

Summary of content (16 pages)

PAGE 1
LTC2903-1 Precision Quad Supply Monitor in 6-Lead SOT-23 U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Ultralow Voltage Reset: VCC = 0.5V Guaranteed Monitor Four Inputs Simultaneously 3.3V, 2.5V, 1.8V, ADJ (LTC2903-A1) 5V, 3.3V, 2.5V, 1.8V (LTC2903-B1) 5V, 3.3V, 1.8V, –5.2V (LTC2903-C1) 3.3V, ADJ, ADJ, ADJ (LTC2903-D1) 5V, ADJ, ADJ, ADJ (LTC2903-E1) Guaranteed Threshold Accuracy: ±1.
PAGE 2
LTC2903-1 U W U U W W W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Notes 1, 2, 3) V1, V2 ...................................................... – 0.3V to 6.5V V3 ................................................. 2.7V or (VCC + 0.3V) V4 (LTC2903-A1, -B1, -D1, -E1) ...............– 0.3V to 6.5V V4 (LTC2903-C1) .................................... – 6.5V to 0.3V RST ........................................................ – 0.3V to 6.5V Operating Temperature Range LTC2903C-X1 ...............
PAGE 3
LTC2903-1 ELECTRICAL CHARACTERISTICS (LTC2903-D1) The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3.3V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VRT33 3.3V, 5% Reset Threshold V1 Input Threshold ● 3.036 3.086 3.135 V VRTAV2 V2 Adjustable Threshold V2 Input Threshold ● 0.492 0.500 0.508 V VRTAV3 V3 Adjustable Threshold V3 Input Threshold ● 0.492 0.500 0.
PAGE 4
LTC2903-1 U W TYPICAL PERFOR A CE CHARACTERISTICS 5V Threshold Voltage vs Temperature 3.3V Threshold Voltage vs Temperature 2.975 4.475 4.450 4.425 4.400 4.375 4.350 –50 –25 0 25 50 TEMPERATURE (°C) 75 2.250 THRESHOLD VOLTAGE, VRT25 (V) THRESHOLD VOLTAGE, VRT33 (V) 4.500 THRESHOLD VOLTAGE, VRT50 (V) 2.5V Threshold Voltage vs Temperature 2.950 2.925 2.900 2.875 –50 100 0 25 50 TEMPERATURE (°C) –25 75 29031 G01 1.605 1.595 1.585 1.575 75 0.505 0.500 0.
PAGE 5
LTC2903-1 U W TYPICAL PERFOR A CE CHARACTERISTICS 260 TYPICAL TRANSIENT DURATION (µs) LTC2903-E1 20 LTC2903-D1 15 10 5 0 –50 –25 75 0 25 50 TEMPERATURE (°C) 350 300 250 RESET OCCURS ABOVE CURVE 200 150 100 50 0 1 10 100 0.1 RESET COMPARATOR OVERDRIVE (% OF VRTX) 100 RST Output Voltage with 10k Pull-Up to V1 2.5 2.0 1.5 1.0 0 25 50 TEMPERATURE (°C) 0.10 75 100 VIN = V1 = V2 = V3 0.08 0.20 0.15 V1 ONLY 0.10 2.5 3 V1 (V) 3.5 4 4.5 0 5 20µA 0.06 10µA 0.05 0.04 5µA 0.03 0.
PAGE 6
LTC2903-1 U W TYPICAL PERFOR A CE CHARACTERISTICS RST Pull-Up Current vs V2 RST Pull-Up Current vs V1 –90 –80 LTC2903-A1, -B1, -C1 –80 V1, V3, V4 ABOVE THRESHOLD LTC2903-D1, -E1 –70 V2, V3, V4 ABOVE THRESHOLD –70 –60 IRST (µA) IRST (µA) –60 –50 –40 LTC2903-D1 –40 –30 –30 –20 –20 VRT25 VRT33 0 0.5 1 1.5 2 2.5 3 V2 (V) 3.5 LTC2903-E1 –10 –10 0 –50 4.5 4 0 5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.
PAGE 7
LTC2903-1 U U U PI FU CTIO S V1 (Pin 1): Voltage Input 1. Internal VCC is generated from the greater voltage on the V1 and V2 inputs. VCC = V1 for options D1 and E1. Bypass this pin to ground with a 0.1µF (or greater) capacitor. V3 is an adjustable input for options D1 and E1. See Table 1b for recommended ADJ resistor values. GND (Pin 2): Ground. V4 (Pin 5): Voltage Input 4. Table 1 lists the recommended ADJ resistor values for options A1, B1 and C1. See Table 1b for options D1 and E1.
PAGE 8
LTC2903-1 W BLOCK DIAGRA S V1 1 (LTC2903-A1, LTC2903-B1) – V1 + POWER DETECT V2 VCC V2 10µA V2 3 – RESET DELAY GENERATOR + V3 4 200ms DELAY – V1 V2 V3 + V4 5 6 RST LOW VOLTAGE PULL-DOWN MONITORED VOLTAGES – + BANDGAP REFERENCE GND 2 A1 B1 V1 3.3V 5V V2 2.5V 3.3V V3 1.8V 2.5V V4 ADJ 1.8V 29031 BD1 0.
PAGE 9
LTC2903-1 W BLOCK DIAGRA S (LTC2903-D1, LTC2903-E1) – V1 1 POWER DETECT V1 + VCC V1 10µA – V2 3 RESET DELAY GENERATOR + 6 RST 200ms DELAY – V3 4 V1 + LOW VOLTAGE PULL-DOWN MONITORED VOLTAGES – V4 5 + BANDGAP REFERENCE GND 2 D1 E1 V1 3.3V 5V V2 ADJ ADJ V3 ADJ ADJ V4 ADJ ADJ 29031 BD2 0.5V U W U U APPLICATIO S I FOR ATIO The LTC2903-1 issues a logic low on the RST output when an input supply voltage resides below the prescribed threshold voltage.
PAGE 10
LTC2903-1 U W U U APPLICATIO S I FOR ATIO current sinking ability for single supply and triple supplytracking applications. Figure 2 shows a detailed view of the reset pin voltage with a 10k pull-up resistor to V1. The LTC2903-1 supervisors derive their internal supply voltage (VCC) automatically from the greater voltage on the V1 and V2 inputs (VCC = V1 for options D1 and E1). With all supply inputs above threshold, the quiescent current drawn from VCC is 20µA (typ).
PAGE 11
LTC2903-1 U W U U APPLICATIO S I FOR ATIO Table 1a. Suggested 1% Resistor Values for the –11.5% ADJ Inputs VSUPPLY (V) VTRIP (V) R1 (kΩ) R2(kΩ) 12 10.75 2050 100 10 8.95 1690 100 8 7.15 1330 100 7.5 6.7 1240 100 6 5.38 976 100 5 4.435 787 100 3.3 2.935 487 100 3 2.66 432 100 2.5 2.2 340 100 1.8 1.605 221 100 1.5 1.325 165 100 1.2 1.065 113 100 1 0.884 76.8 100 0.9 0.
PAGE 12
LTC2903-1 U W U U APPLICATIO S I FOR ATIO The powered system must work reliably down to the lowest voltage in the threshold band or risk malfunction before the reset line falls. In the 5V example, using the 1.5% accurate supervisor, the system ICs must work down to 4.35V. System ICs working with a ±2.5% accurate supervisor must operate down to 4.25V, increasing the required system voltage margin and the probability of system malfunction.
PAGE 13
LTC2903-1 U TYPICAL APPLICATIO S Quad Supply Monitor with Adjustable Input 1 3.3V C1 0.1µF V1 RST 6 SYSTEM RESET LTC2903-A1 2 GND V4 R1 76.8k 5 R2 100k C2 0.1µF 3 2.5V V2 V3 4 1V (VTRIP = 0.884V) 1.8V 2903 TA02 Fixed Quad Supply Monitor with LED Indication on RST 5V 1k LED 1 5V C1 0.1µF V1 RST 6 SYSTEM RESET LTC2903-B1 2 GND V4 V2 V3 5 1.8V C2 0.1µF 3.3V 3 4 2.
PAGE 14
LTC2903-1 U TYPICAL APPLICATIO S Quad Supply Monitor with Unused Input Pulled Above Threshold 1 5V C1 0.1µF V1 RST 6 SYSTEM RESET LTC2903-C1 2 GND V4 V2 V3 5 –5.2V C2 0.1µF 3 3.3V 4 2903 TA03 Quad Supply Monitor with 3 Adjustable Inputs Monitoring 5% Supplies 1 3.3V C1 0.1µF V1 RST 6 SYSTEM RESET LTC2903-D1 2 GND V4 2150k 5 12V (VTRIP = 11.25V) 100k 237k 1.8V (VTRIP = 1.685V) 3 100k V2 V3 2903 TA06 365k 4 100k 2.5V (VTRIP = 2.
PAGE 15
LTC2903-1 U PACKAGE DESCRIPTIO S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 MAX 2.90 BSC (NOTE 4) 0.95 REF 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 6 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) 1.90 BSC S6 TSOT-23 0302 NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3.
PAGE 16
LTC2903-1 U TYPICAL APPLICATIO Quad Supply Monitor with Manual Reset Button 3.3V R3 10k 3.3V V1 C1 0.1µF RST LTC2903-A1 GND SYSTEM RESET 12V (VTRIP = 10.75V) V4 R2 100k C2 0.1µF V2 2.5V MANUAL RESET BUTTON R1 RESD* (NORMALLY OPEN) 2050k 10k 1.8V V3 2903 TA04 *OPTIONAL RESISTOR RECOMMENDED TO EXTEND ESD TOLERANCE RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC690 5V Supply Monitor, Watchdog Timer and Battery Backup 4.65 Threshold LTC694-3.3 3.