Datasheet

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LT1490A/LT1491A

sn1490, 14901afbs

Dual/Quad Over-The-Top

Micropower Rail-to-Rail

Input and Output Op Amps

■

Low Input Offset Voltage: 500

V Max

■

Output Swings to 10mV Max from V

–

■

Rail-to-Rail Input and Output

■

Micropower: 50

µµ

µA/Amplifier Max

■

Over-The-Top

Input Common Mode Range Extends

44V Above V

–

, Independent of V

■

Specified on 3V, 5V and ±15V Supplies

■

High Output Current: 20mA

■

Output Drives 10,000pF with Output Compensation

■

Reverse Battery Protection to 18V

■

No Supply Sequencing Problems

■

High Voltage Gain: 1500V/mV

■

High CMRR: 98dB

■

No Phase Reversal

■

Gain Bandwidth Product: 200kHz

■

Tiny 3mm × 3mm × 0.8mm DFN Package

The LT

1490A/LT1491A are dual and quad op amps with a

low input offset voltage of 500µV max. The LT1490A/LT1491A

operate on all single and split supplies with a total voltage of

2V to 44V, drawing only 40µA of quiescent current per

amplifier. These amplifiers are reverse supply protected;

they draw virtually no current for reverse supply up to 18V.

The input range of the LT1490A/LT1491A includes both

supplies and the output swings to both supplies. Unlike most

micropower op amps, the LT1490A/LT1491A can drive

heavy loads; their rail-to-rail outputs drive 20mA. The

LT1490A/LT1491A are unity-gain stable and drive all capaci-

tive loads up to 10,000pF when optional 0.22µF and 150Ω

compensation is used.

The LT1490A/LT1491A have a unique input stage that oper-

ates and remains high impedance when above the positive

supply. The inputs take 44V both differential and common

mode even when operating on a 3V supply. Built-in resistors

protect the inputs for faults below the negative supply up to

15V. There is no phase reversal of the output for inputs 15V

below V

–

or 44V above V

–

, independent of V

The LT1490A dual op amp is available in the 8-pin MSOP,

PDIP and SO packages. For space limited applications

LT1490A is available in a 3mm × 3mm × 0.8mm, dual fine

pitch leadless package (DFN). The quad LT1491A is available

in the 14-pin SO, PDIP and 5mm × 3mm × 0.8mm DFN

packages.

■

Battery- or Solar-Powered Systems

Portable Instrumentation

Sensor Conditioning

■

Supply Current Sensing

■

Battery Monitoring

■

Micropower Active Filters

■

4mA to 20mA Transmitters

Battery Monitor

–

2N3904

S1 = OPEN, GAIN = 1

S1 = CLOSED, GAIN = 10

= R

= 5V, 0V

10k

90.9k

OUT

LOGIC

1490A TA01

LOGIC HIGH (5V) = CHARGING

LOGIC LOW (0V) = DISCHARGING

10k

2N3904

0.2Ω

CHARGER

VOLTAGE

1/4 LT1491A

BATT

= 12V

BATT

LOAD

–

OUT

)(R

)(GAIN)

OUT

GAIN

BATT

= = AMPS

1/4 LT1491A

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

Over-The-Top is a registered trademark of Linear Technology Corporation.

Protected by U.S. Patents including 5825228.

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

Summary of content (16 pages)

PAGE 1
LT1490A/LT1491A Dual/Quad Over-The-Top Micropower Rail-to-Rail Input and Output Op Amps U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Low Input Offset Voltage: 500µV Max Output Swings to 10mV Max from V – Rail-to-Rail Input and Output µA/Amplifier Max Micropower: 50µ ® Over-The-Top Input Common Mode Range Extends 44V Above V –, Independent of V + Specified on 3V, 5V and ±15V Supplies High Output Current: 20mA Output Drives 10,000pF with Output Compensation Reverse Battery Protection to 18V No Supp
PAGE 2
LT1490A/LT1491A W W W AXI U U ABSOLUTE RATI GS (Note 1) Total Supply Voltage (V + to V –) ............................. 44V Differential Input Voltage ........................................ 44V Input Current (Note 9) ....................................... ±12mA Output Short-Circuit Duration (Note 2) ........ Continuous Operating Temperature Range (Note 3) LT1490AC/LT1491AC ......................... – 40°C to 85°C LT1490AI/LT1491AI ........................... – 40°C to 85°C LT1490AH/LT1491AH .....
PAGE 3
LT1490A/LT1491A ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range of – 40°C ≤ TA ≤ 85°C, otherwise specifications are at TA = 25°C. VS = 3V, 0V; VS = 5V, 0V; VCM = VOUT = half supply unless otherwise noted.
PAGE 4
LT1490A/LT1491A ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range of – 40°C ≤ TA ≤ 85°C, otherwise specifications are at TA = 25°C. VS = 3V, 0V; VS = 5V, 0V; VCM = VOUT = half supply unless otherwise noted. (Note 4) SYMBOL PSRR PARAMETER CONDITIONS Power Supply Rejection Ratio VS = 2.5V to 12.
PAGE 5
LT1490A/LT1491A ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range of – 40°C ≤ TA ≤ 85°C, otherwise specifications are at TA = 25°C. VS = ±15V; VCM = 0V, VOUT = 0V unless otherwise noted. (Note 4) SYMBOL PARAMETER CONDITIONS LT1490AC/LT1491AC LT1490AI/LT1491AI MIN TYP MAX ISC Short-Circuit Current (Note 2) Short to GND 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C ● ● ±20 ±15 ±10 VS = ±1.
PAGE 6
LT1490A/LT1491A ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range of – 40°C ≤ TA ≤ 125°C. VS = ±15V, VCM = 0V, VOUT = 0V unless otherwise noted. (Note 4) SYMBOL PARAMETER IS Supply Current per Amplifier (Note 7) LT1490AH/LT1491AH MIN TYP MAX CONDITIONS 40 ● GBW SR VOS Gain Bandwidth Product (Note 6) Slew Rate (Note 8) Input Offset Voltage (Note 5) f = 1kHz UNITS µA µA 50 70 110 60 180 ● kHz kHz 0.035 0.015 0.
PAGE 7
LT1490A/LT1491A U W TYPICAL PERFOR A CE CHARACTERISTICS Supply Current vs Supply Voltage TA = 125°C 60 TA = 25°C 50 40 TA = –55°C 30 20 10 0 5 0 10 15 20 25 30 35 40 TOTAL SUPPLY VOLTAGE (V) 400 5000 300 3000 200 100 TA = –55°C TA = 25°C 0 –100 –200 –300 – 400 45 VS = 5V, 0V INPUT BIAS CURRENT (nA) CHANGE IN INPUT OFFSET VOLTAGE (µV) SUPPLY CURRENT PER AMPLIFIER (µA) 80 70 Input Bias Current vs Common Mode Voltage Minimum Supply Voltage TA = –55°C 10µ 1m 10m 100µ SOURCING LOAD CU
PAGE 8
LT1490A/LT1491A U W TYPICAL PERFOR A CE CHARACTERISTICS Gain and Phase Shift vs Frequency Gain Bandwidth Product vs Temperature 40 30 20 20 0 GAIN 10 –20 0 – 40 –10 – 60 –20 – 80 10 100 FREQUENCY (kHz) 200 VS = ±15V 180 VS = ±1.
PAGE 9
LT1490A/LT1491A U W TYPICAL PERFOR A CE CHARACTERISTICS Undistorted Output Swing vs Frequency 35 10 0 –2 –4 40 AV = 1 AV = 2 AV = 10 AV = 5 30 20 40 60 80 100 120 140 160 SETTLING TIME (µs) 10 100 1000 CAPACITIVE LOAD (pF) 10000 1490A G19 1490A F20 1490A G21 Total Harmonic Distortion + Noise vs Frequency Total Harmonic Distortion + Noise vs Load Resistance Total Harmonic Distortion + Noise vs Output Voltage 0.01 1 RL = 10k VCM = HALF SUPPLY f = 1kHz 1 VS = ±1.5V VIN = ±1V 0.
PAGE 10
LT1490A/LT1491A U W U U APPLICATIO S I FOR ATIO Supply Voltage The positive supply pin of the LT1490A/LT1491A should be bypassed with a small capacitor (about 0.01µF) within an inch of the pin. When driving heavy loads an additional 4.7µF electrolytic capacitor should be used. When using split supplies, the same is true for the negative supply pin. The LT1490A/LT1491A are protected against reverse battery voltages up to 18V.
PAGE 11
LT1490A/LT1491A U W U U APPLICATIO S I FOR ATIO Gain in single supply applications where the load is returned to ground. The typical performance photo of Open-Loop Gain for various loads shows the details. The open-loop gain is almost independent of load when the output is sourcing current.
PAGE 12
LT1490A/LT1491A U PACKAGE DESCRIPTIO DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) R = 0.115 TYP 5 0.38 ± 0.10 8 0.675 ±0.05 3.5 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) 1.65 ± 0.10 (2 SIDES) 3.00 ±0.10 (4 SIDES) PIN 1 TOP MARK (NOTE 6) PACKAGE OUTLINE (DD8) DFN 1203 0.25 ± 0.05 4 0.25 ± 0.05 0.75 ±0.05 0.200 REF 0.50 BSC 2.38 ±0.05 (2 SIDES) 1 0.50 BSC 2.38 ±0.10 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1.
PAGE 13
LT1490A/LT1491A U PACKAGE DESCRIPTIO N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) .400* (10.160) MAX 8 7 6 5 1 2 3 4 .255 ± .015* (6.477 ± 0.381) .300 – .325 (7.620 – 8.255) .065 (1.651) TYP .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 .130 ± .005 (3.302 ± 0.127) .045 – .065 (1.143 – 1.651) ) .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 .100 (2.54) BSC (0.457 ± 0.076) N8 1002 NOTE: 1.
PAGE 14
LT1490A/LT1491A U PACKAGE DESCRIPTIO N Package 14-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) .770* (19.558) MAX 14 13 12 11 10 9 8 1 2 3 4 5 6 7 .255 ± .015* (6.477 ± 0.381) .130 ± .005 (3.302 ± 0.127) .300 – .325 (7.620 – 8.255) .045 – .065 (1.143 – 1.651) .020 (0.508) MIN .065 (1.651) TYP .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 ) .005 (0.127) .100 MIN (2.54) BSC .120 (3.048) MIN NOTE: 1. DIMENSIONS ARE .018 ± .003 (0.457 ± 0.
PAGE 15
LT1490A/LT1491A U PACKAGE DESCRIPTIO DHC Package 16-Lead Plastic DFN (5mm × 3mm) (Reference LTC DWG # 05-08-1706) 0.65 ±0.05 3.50 ±0.05 1.65 ±0.05 2.20 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 4.40 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS R = 0.115 TYP 5.00 ±0.10 (2 SIDES) R = 0.20 TYP 3.00 ±0.10 (2 SIDES) 9 0.40 ± 0.10 16 1.65 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) PIN 1 NOTCH (DHC16) DFN 1103 8 0.200 REF 1 0.25 ± 0.05 0.50 BSC 0.75 ±0.05 4.40 ±0.
PAGE 16
LT1490A/LT1491A U TYPICAL APPLICATIO Ring-Tone Generator 60V R16 100k R2 47k R3 10k C2 0.47µF 3 + R1 1/4 LT1491A 33k 2 1 D1 1N4148 R5 100k 5 – 7 R9 300k R11 10k 10 C4 0.068µF 9 + 8 13 – R4 1.6M R8 620k CADENCE OSCILLATOR R10 620k R12 SMOOTHING FILTER 10k R14 10k R13 130k R15 47k 20Hz OSCILLATOR C5 0.01µF 4 – 1/4 LT1491A 12 C1 1µF + R24 11 420 14 C7 47µF R18 100Ω R26 2k R23 4.7k OPTO1* R25 4.