Document
LT1490A/LT1491A
Dual/Quad Over-The-Top Micropower Rail-to-Rail
Input and Output Op Amps
FEATURES
DESCRIPTION
n Low Input Offset Voltage: 500μV Max n Output Swings to 10mV Max from V– n Rail-to-Rail Input and Output n Micropower: 50μA/Amplifier Max n Over-The-Top® Input Common Mode Range Extends
44V Above V–, Independent of V+ n Specified on 3V, 5V and ±15V Supplies n High Output Current: 20mA n Output Drives 10,000pF with Output Compensation n Reverse Battery Protection to 18V n No Supply Sequencing Problems n High Voltage Gain: 1500V/mV n High CMRR: 98dB n No Phase Reversal n Gain Bandwidth Product: 200kHz n Tiny 3mm × 3mm × 0.8mm DFN Package
APPLICATIONS
n Battery- or Solar-Powered Systems Portable Instrumentation Sensor Conditioning
n Supply Current Sensing n Battery Monitoring n Micropower Active Filters n 4mA to 20mA Transmitters
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 capacitive loads up to 10,000pF when optional 0.22μF and 150Ω compensation is used.
The LT1490A/LT1491A have a unique input stage that operates 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.
L, LT, LTC, LTM, Over-The-Top, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5825228.
TYPICAL APPLICATION
Battery Monitor
CHARGER VOLTAGE
RS 0.2Ω
RA 2k
+
Q1 2N3904
IBATT
RA´ 2k
1/4 LT1491A
–
–
1/4 LT1491A
LOGIC
+
LOAD
RB 2k
RB´ 2k
+
VBATT = 12V
Q2
+ 2N3904
1/4 LT1491A
–
S1
RG 10k
10k
LOGIC HIGH (5V) = CHARGING LOGIC LOW (0V) = DISCHARGING
+
1/4 LT1491A
–
90.9k
VOUT
1490A TA01
IBATT
=
VOUT
=
(RS)(RG/RA)(GAIN)
VOUT AMPS GAIN
S1 = OPEN, GAIN = 1 S1 = CLOSED, GAIN = 10
RA = RB VS = 5V, 0V
14901afd
1
LT1490A/LT1491A
ABSOLUTE MAXIMUM RATINGS (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......................... –40°C to 125°C
Specified Temperature Range (Note 4) LT1490AC/LT1490AI ............................–40°C to 85°C LT1491AC/LT1491AI.............................–40°C to 85°C LT1490AH/LT1491AH......................... –40°C to 125°C
Junction Temperature .......................................... 150°C Junction Temperature (DD/DHC Package) ........... 125°C Storage Temperature Range ................. –65°C to 150°C Storage Temperature Range
DD/DHC Package .............................. –65°C to 125°C Lead Temperature (Soldering, 10 sec).................. 300°C
PIN CONFIGURATION
LT1490A
OUT A 1 –IN A 2 +IN A 3
V– 4
TOP VIEW
A B
8 V+ 7 OUT B 6 –IN B 5 +IN B
MS8 PACKAGE 8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 250°C/W
LT1490A
OUT A 1 –IN A 2 +IN A 3
V– 4
TOP VIEW
A B
8 V+ 7 OUT B 6 –IN B 5 +IN B
N8 PACKAGE
S8 PACKAGE
8-LEAD PDIP 8-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 130°C/W (N8) TJMAX = 150°C, θJA = 190°C/W (S8)
LT1491A
TOP VIEW
OUT A 1 –IN A 2 +IN A 3
V+ 4 +IN B 5 –IN B 6 OUT B 7
A B
14 OUT D 13 –IN D D 12 +IN D 11 V – 10 +IN C C 9 –IN C 8 OUT C
N PACKAGE 14-LEAD PDIP
S PACKAGE 14-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 110°C/W (N) TJMAX = 150°C, θJA = 150°C/W (S)
LT1491A
LT1490A
TOP VIEW
OUT A 1 –IN A 2 +IN A 3
V– 4
A
8 V+ 7 OUT B 6 –IN B B 5 +IN B
DD PACKAGE 8-LEAD (3mm w 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 160°C/W (NOTE 2) UNDERSIDE METAL CONNECTED TO V–
TOP VIEW
OUT A 1 –IN A 2 +IN A 3
V+ 4 +IN B 5 –IN B 6 OUT B 7
NC 8
A B
16 OUT D 15 –IN D D 14 +IN D 13 V– 12 +IN C C 11 –IN C 10 OUT C 9 NC
DHC16 P.