LT1635
Micropower Rail-to-Rail
Op Amp and Reference
FEATURES
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DESCRIPTION
The LT
®
1635 is a new analog building block that includes a
rail-to-rail output op amp, a precision reference and reference
buffer. The device operates from supplies as low as a single
1.2V or up to
±5V,
yet it consumes only 130µA of supply
current.
The input common mode range of the op amp includes
ground and incorporates phase reversal protection to pre-
vent false outputs from occurring when the input is below
the negative supply. The rail-to-rail output stage can swing to
within 15mV of each rail with no load and can swing to within
250mV of each rail while delivering 10mA of output current.
The gain bandwidth of the op amp is 175kHz and it is unity-
gain stable with up to 1000pF load capacitance.
The 0.2V reference is referred to V
–
and includes a buffer
amplifier to enhance flexibility. The reference and buffer
combine to achieve a drift of 30ppm/°C, a line regulation of
20ppm/V and a load regulation of 150ppm/mA.
The LT1635 is available in 8-pin PDIP and SO packages, and
has the industry standard LM10 pinout.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Guaranteed Operation at 1.2V
Op Amp and Reference on Single Chip
Micropower: 130
µ
A Supply Current
Industrial Temperature Range SO-8 Packages
Rail-to-Rail Output
High Output Current: 25mA Min
Output Drives 1000pF
Capable of Floating Mode Operation
Specified for 5V and
±5V
Supplies
Low Reference Drift: 30ppm/°C
Industry Standard LM10 Pinout
APPLICATIONS
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Battery- or Solar-Powered Systems
Portable Instrumentation
Sensor Conditioning
Precision Current Regulators
Precision Voltage Regulators
Battery Level Indicator
Thermocouple Transmitter
TYPICAL APPLICATION
0V to 5V Regulator
C1
0.01µF
V
IN
> 5.2V
PERCENT OF UNITS
Typical Distribution of Input Offset Voltage
25
V
S
= 5V, 0V
T
A
= 25°C
20
R1
100k
15
R2
3.9k
V
OUT
ADJ
+
3
–
2
7
LT1635
4
8
1
R3
5k
1635 TA01
10
6
V
OUT
0V TO 5V
5
0
– 1.0
– 0.6
0.2
0.6
– 0.2
INPUT OFFSET VOLTAGE (mV)
U
U
U
1.0
1635 TA02
1
LT1635
ABSOLUTE
MAXIMUM
RATINGS
Total Supply Voltage (V
+
to V
–
) .............................. 14V
Input Differential Voltage ......................................... 14V
Input Current ......................................................
±25mA
Output Short-Circuit Duration .......................Continuous
Operating Temperature Range
(Note 1) .............................................. – 40°C to 85°C
Junction Temperature ........................................... 150°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
REFOUT 1
OP AMP IN (–) 2
OP AMP IN (+) 3
V
–
4
N8 PACKAGE
8-LEAD PDIP
–
+
+
–
+
ORDER PART
NUMBER
8 REF FB
7 V
+
6 OP AMP OUT
5 BALANCE
LT1635CN8
LT1635CS8
LT1635IN8
LT1635IS8
S8 PART
MARKING
1635
1635I
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 130°C/ W (N8)
T
JMAX
= 150°C,
θ
JA
= 190°C/ W (S8)
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
5V OP AMP:
V
S
= 5V, 0V; V
CM
= V
OUT
= 2.5V, T
A
= 25°C, unless otherwise noted. (Note 1)
SYMBOL
V
OS
PARAMETER
Input Offset Voltage
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
Input Offset Voltage Drift
V
OS
ADJ
I
OS
I
B
Offset Voltage Adjust Range
Input Offset Current
Input Bias Current
q
q
q
q
q
q
q
CONDITIONS
MIN
TYP
0.3
0.5
3.0
MAX
1.3
1.6
1.8
7.0
UNITS
mV
mV
mV
µV/°C
mV
mV
– 40°C
≤
T
A
≤
85°C (Note 3)
Positive Adjust
Negative Adjust
6
– 1.4
8
–2
0.2
2.0
2.5
1
50
0.05
0.6
4.0
5.0
Input Noise Voltage
e
n
i
n
R
IN
Input Noise Voltage Density
Input Noise Current Density
Input Resistance
Input Voltage Range
CMRR
A
VOL
Common Mode Rejection Ratio
Large-Signal Voltage Gain
0.1Hz to 10Hz
f = 1kHz
f = 1kHz
Differential
Common Mode, V
CM
= 0V to 4V
V
CM
= 0V to 4V
q
q
q
µV
P-P
nV/√Hz
pA/√Hz
MΩ
GΩ
4
V
dB
dB
V/mV
V/mV
V/mV
V/mV
V/mV
V/mV
10
250
500
mV
mV
mV
V
V
V
7
0
92
85
100
45
35
15
8
25
6
110
97
450
200
150
25
20
2
125
200
V
O
= 200mV to 4.5V, No Load
V
O
= 200mV to 4.5V, R
L
= 1.1k
V
O
= 200mV to 4.5V, R
L
= 500Ω
I
OUT
= 0.1mA to 5mA
V
O
= 1.5V to 6.45V
(Note 4)
V
S
= 5V, No Load
V
S
= 5V, I
SINK
= 5mA
V
S
= 5V, I
SINK
= 10mA
V
S
= 5V, No Load
V
S
= 5V, I
SOURCE
= 5mA
V
S
= 5V, I
SOURCE
= 10mA
q
q
q
Shunt Gain
q
q
q
q
q
q
q
V
OL
Output Voltage Swing Low
V
OH
Output Voltage Swing High
4.975
4.65
4.55
4.985
4.8
4.75
2
U
W
U
U
W W
W
nA
nA
nA
LT1635
ELECTRICAL CHARACTERISTICS
5V OP AMP:
V
S
= 5V, 0V; V
CM
= V
OUT
= 2.5V, T
A
= 25°C, unless otherwise noted. (Note 1)
SYMBOL
I
SC
PSRR
PARAMETER
Short-Circuit Current
Power Supply Rejection Ratio
Minimum Operating Supply Voltage
I
S
GBW
SR
Supply Current
q
CONDITIONS
V
S
= 5V, Short to GND
V
S
= 5V, Short to V
CC
V
S
= 1.2V to 12V, V
CM
= V
O
= 0.2V
q
q
q
MIN
25
25
93
90
TYP
40
40
100
97
1.1
130
150
175
0.045
MAX
UNITS
mA
mA
dB
dB
(Note 2)
q
1.2
200
260
V
µA
µA
kHz
V/µs
Gain Bandwidth Product
Slew Rate
f = 1kHz
A
V
= – 1, R
L
=
∞
5V REFERENCE:
V
S
= 5V, 0V; T
A
= 25°C, unless otherwise noted. (Note 1)
SYMBOL
V
REF
TC V
REF
PARAMETER
Feedback Sense Voltage
Reference Drift
Feedback Current
Line Regulation
CONDITIONS
Voltage at Pin 1 with Pin 1 Connected
to Pin 8 (Note 5)
(Note 3)
Current into Pin 8
q
q
q
MIN
189
TYP
200
30
3.5
5.0
20
30
150
200
MAX
211
100
10
15
35
55
300
500
UNITS
mV
ppm/°C
nA
nA
ppm/V
ppm/V
ppm/mA
ppm/mA
V/mV
V/mV
0
≤
I
REF
≤
1mA, V
REF
= 200mV
V
S
= 1.2V to 5V
V
S
= 1.3V to 5V (Note 2)
I
REF
= 0 to 1mA
q
q
Load Regulation
Reference Amplifier Gain
V
O
= 0.2V to 3.5V
q
45
25
90
50
±5V
OP AMP:
V
S
=
±5V;
V
CM
= V
OUT
= 0V, T
A
= 25°C, unless otherwise noted. (Note 1)
SYMBOL
V
OS
PARAMETER
Input Offset Voltage
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
Input Offset Voltage Drift
V
OS
ADJ
I
OS
I
B
Offset Voltage Adjust Range
Input Offset Current
Input Bias Current
q
q
q
q
q
q
q
CONDITIONS
MIN
TYP
0.3
0.5
4.5
MAX
1.5
1.9
2.1
10.0
UNITS
mV
mV
mV
µV/°C
mV
mV
0°C
≤
T
A
≤
85°C (Note 3)
Positive Adjust
Negative Adjust
6
– 1.4
8
–2
0.2
2.0
2.5
1
50
0.05
0.6
4
5
nA
nA
nA
µV
P-P
nV/√Hz
pA/√Hz
MΩ
GΩ
Input Noise Voltage
e
n
i
n
R
IN
Input Noise Voltage Density
Input Noise Current Density
Input Resistance
Input Voltage Range
CMRR
Common Mode Rejection Ratio
0.1Hz to 10Hz
f = 1kHz
f = 1kHz
Differential
Common Mode, V
CM
= – 5V to 4V
V
CM
= – 5V to 4V
q
q
q
7
–5
94
91
35
9
4
115
110
V
dB
dB
3
LT1635
ELECTRICAL CHARACTERISTICS
±5V
OP AMP:
V
S
=
±5V;
V
CM
= V
OUT
= 0V, T
A
= 25°C, unless otherwise noted. (Note 1)
SYMBOL
A
VOL
PARAMETER
Large-Signal Voltage Gain
CONDITIONS
V
O
= – 4.5V to 4.5V, No Load
V
O
= – 4.5V to 4.5V, R
L
= 1.1k
V
O
= – 4.5V to 4.5V, R
L
= 500Ω
V
S
=
±5V,
No Load
V
S
=
±5V,
I
SINK
= 5mA
V
S
=
±5V,
I
SINK
= 10mA
V
S
=
±5V
V
S
=
±1V
to
±6V,
V
CM
= V
O
= 0V
q
q
q
q
q
q
q
MIN
175
15
10
±4.975
±4.65
±4.5
±25
90
88
TYP
300
100
60
±4.985
±4.75
±4.6
±40
100
98
135
160
175
0.05
MAX
UNITS
V/mV
V/mV
V/mV
mV
mV
mV
mA
dB
dB
V
O
Output Voltage Swing
I
SC
PSRR
I
S
GBW
SR
Short-Circuit Current
Power Supply Rejection Ratio
Supply Current
q
215
280
µA
µA
kHz
V/µs
Gain Bandwidth Product
Slew Rate
f = 1kHz
A
V
= –1, R
L
=
∞
±5V
REFERENCE:
V
S
=
±5V,
T
A
= 25°C, unless otherwise noted. (Note 1)
SYMBOL
V
REF
TC V
REF
PARAMETER
Feedback Sense Voltage
Reference Drift
Feedback Current
Line Regulation
CONDITIONS
Voltage at Pin 1 with Pin 1 Connected
to Pin 8 (Note 5)
(Note 3)
Current into Pin 8
q
q
q
MIN
189
TYP
200
40
3.5
5.0
20
30
150
200
MAX
211
120
10
15
25
55
300
500
UNITS
mV
ppm/°C
nA
nA
ppm /V
ppm/V
ppm/mA
ppm/mA
V/mV
V/mV
0
≤
I
REF
≤
1mA, V
REF
= 200mV
V
S
=
±0.6V
to
±5V
V
S
=
±0.65V
to
±5V
(Note 2)
I
REF
= 0 to 1mA
q
q
Load Regulation
Reference Amplifier Gain
V
O
= 0.2V to 8.5V
V
S
= 10V, 0V
q
45
25
90
50
The
q
denotes specifications that apply over the full operating temperature
range.
Note 1:
The LT1635C is guaranteed to operate over the commercial
temperature range of 0°C to 70°C. It is designed, characterized and
expected to meet these extended temperature limits, but is not tested at
– 40°C and 85°C. The LT1635I is guaranteed to meet the industrial
temperature range.
Note 2:
The LT1635 op amp operates on a 1.2V supply over the full
industrial temperature range with an input common mode of 0V to 0.2V.
The minimum supply voltage for the reference to operate properly over
this temperature range is 1.3V.
Note 3:
This parameter is not 100% tested. Temperature coefficient is
measured by dividing the change in output voltage by specified
temperature range.
Note 4:
Shunt gain defines the operation in floating applications when the
output is connected to the V
+
terminal and input common mode is
referred to V
–
.
Note 5:
If part is stored outside of the specified temperature range, the
output may shift due to hysteresis.
4
LT1635
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
OFFSET CURRENT (pA)
220
200
SUPPLY CURRENT (µA)
180
160
140
120
100
80
60
2
3
6
7
4
5
8
SUPPLY VOLTAGE (V)
9
10
T
A
= 125°C
T
A
= 25°C
INPUT BIAS CURRENT (nA)
T
A
= – 55°C
BIAS CURRENT (nA)
0.1Hz to 10Hz Noise Voltage
INPUT NOISE VOLTAGE DENSITY (nV/√Hz)
V
S
=
±
5V
T
A
= 25°C
80
INPUT NOISE CURRENT DENSITY (pA/√Hz)
NOISE VOLTAGE (1µV/DIV)
0
1
2
3
4 5 6
TIME (SEC)
7
Typical Distribution of Offset
Voltage Drift with Temperature
25
200
CHANGE IN INPUT OFFSET VOLTAGE (V)
V
S
= 5V, 0V
20
PERCENT OF UNITS
0
– 200
– 400
– 600
– 800
T
A
= 125°C
T
A
= 25°C
T
A
= – 55°C
CHANGE IN OFFSET VOLTAGE (µV)
15
10
5
0
–6
–4
–2
0
2
TCV
OS
(µV/°C)
U W
1635 G01
Op Amp
Input Bias Current
vs Common Mode Voltage
0
V
S
= 5V, 0V
–1
T
A
= 125°C
T
A
= 25°C
–2
T
A
= – 55°C
–3
Input Bias and Offset Currents
vs Temperature
100
V
S
= 5V, 0V
50
I
OS
0
–1
I
B
–2
–4
–3
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
125
–5
–1
0
2
3
1
COMMON MODE VOLTAGE (V)
4
1635 G03
1635 G02
Noise Voltage Density
vs Frequency
V
S
=
±
2.5V
T
A
= 25°C
Input Noise Current vs Frequency
0.5
V
S
=
±
2.5V
T
A
= 25°C
70
0.4
60
0.3
50
0.2
40
0.1
30
0
1
10
100
FREQUENCY (Hz)
1000
1635 G05
8
9
10
1
10
100
FREQUENCY (Hz)
1000
1635 G06
1635 G04
Minimum Supply Voltage
140
120
100
80
60
40
20
0
Turn-On Drift
of Three Typical Units
–1000
4
6
1635 G07
V
S
=
±
5V
T
A
= 25°C
0
1
7 8 9
4 5 6
2 3
TIME AFTER POWER ON (MINUTES)
10
0
1
TOTAL SUPPLY VOLTAGE (V)
2
1635 G08
1635 G09
5
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