LINER LT1635 Micropower rail-to-rail op amp and reference Datasheet

LT1635
Micropower Rail-to-Rail
Op Amp and Reference
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FEATURES
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DESCRIPTIO
Guaranteed Operation at 1.2V
Op Amp and Reference on Single Chip
Micropower: 130µA Supply Current
Industrial Temperature Range SO-8 Packages
Rail-to-Rail Output
High Output Current: 20mA Min
Output Drives 1000pF
Capable of Floating Mode Operation
Specified for 5V and ±5V Supplies
Low Reference Drift: 30ppm/°C
Industry Standard LM10 Pinout
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APPLICATIO S
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The input common mode range of the op amp includes
ground and incorporates phase reversal protection to prevent 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 unitygain 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.
Battery- or Solar-Powered Systems
Portable Instrumentation
Sensor Conditioning
Precision Current Regulators
Precision Voltage Regulators
Battery Level Indicator
Thermocouple Transmitter
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.
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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.
TYPICAL APPLICATIO
0V to 5V Regulator
Typical Distribution of Input Offset Voltage
C1
0.01µF
25
VS = 5V, 0V
TA = 25°C
3
VOUT
ADJ
–
+
7
6
LT1635
4
VOUT
0V TO 5V
PERCENT OF UNITS
2
R2
3.9k
20
VIN > 5.2V
R1
100k
15
10
5
8
1
0
– 1.0
R3
5k
1635 TA01
– 0.6
0.2
0.6
– 0.2
INPUT OFFSET VOLTAGE (mV)
1.0
1635 TA02
1
LT1635
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ABSOLUTE
RATI GS
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PACKAGE/ORDER I FOR ATIO
(Note 1)
Total Supply Voltage (V + to V –) .............................. 14V
Input Differential Voltage ......................................... 14V
Input Current ...................................................... ±25mA
Output Short-Circuit Duration .......................Continuous
Operating Temperature Range
(Note 2) .............................................. – 40°C to 85°C
Junction Temperature ........................................... 150°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
TOP VIEW
REFOUT 1
–
8 REF FB
OP AMP IN (–) 2
+
7 V+
OP AMP IN (+) 3
–
+
6 OP AMP OUT
+
V– 4
N8 PACKAGE
8-LEAD PDIP
LT1635CN8
LT1635CS8
LT1635IN8
LT1635IS8
5 BALANCE
S8 PACKAGE
8-LEAD PLASTIC SO
S8 PART
MARKING
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 190°C/ W (S8)
1635
1635I
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
5V OP AMP: The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at
TA = 25°C. VS = 5V, 0V; VCM = VOUT = 2.5V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
VOS
Input Offset Voltage
CONDITIONS
MIN
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
●
●
Input Offset Voltage Drift
– 40°C ≤ TA ≤ 85°C (Note 4)
●
VOS ADJ
Offset Voltage Adjust Range
Positive Adjust
Negative Adjust
●
●
IOS
Input Offset Current
IB
Input Bias Current
Input Noise Voltage
6
– 1.4
TYP
MAX
UNITS
0.3
0.5
1.3
1.6
1.8
mV
mV
mV
3.0
7.0
µV/°C
8
–2
mV
mV
●
0.2
0.6
nA
●
2.0
2.5
4.5
5.5
nA
nA
0.1Hz to 10Hz
µVP-P
1
en
Input Noise Voltage Density
f = 1kHz
50
nV/√Hz
in
Input Noise Current Density
f = 1kHz
0.05
pA/√Hz
RIN
Input Resistance
Differential
Common Mode, VCM = 0V to 4V
Input Voltage Range
CMRR
AVOL
Common Mode Rejection Ratio
●
7
●
0
●
92
85
110
97
dB
dB
●
●
●
100
45
35
450
200
150
V/mV
V/mV
V/mV
15
8
25
20
V/mV
V/mV
V/mV
VCM = 0V to 4V
Large-Signal Voltage Gain
VO = 200mV to 4.5V, No Load
VO = 200mV to 4.5V, RL = 1.1k
VO = 200mV to 4.5V, RL = 500Ω
Shunt Gain
IOUT = 0.1mA to 5mA
VO = 1.5V to 6.45V
(Note 5)
●
VOL
Output Voltage Swing Low
VS = 5V, No Load
VS = 5V, ISINK = 5mA
VS = 5V, ISINK = 10mA
●
●
●
VOH
Output Voltage Swing High
VS = 5V, No Load
VS = 5V, ISOURCE = 5mA
VS = 5V, ISOURCE = 10mA
●
●
●
2
25
6
4
2
125
200
4.975
4.65
4.55
MΩ
GΩ
4.985
4.8
4.75
10
250
500
V
mV
mV
mV
V
V
V
LT1635
ELECTRICAL CHARACTERISTICS
5V OP AMP: The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at
TA = 25°C. VS = 5V, 0V; VCM = VOUT = 2.5V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
ISC
Short-Circuit Current
VS = 5V, Short to GND
VS = 5V, Short to VCC
PSRR
Power Supply Rejection Ratio
VS = 1.2V to 12V, VCM = VO = 0.2V
Minimum Operating Supply Voltage
(Note 3)
IS
Supply Current
GBW
Gain Bandwidth Product
f = 1kHz
SR
Slew Rate
AV = – 1, RL = ∞
MIN
TYP
●
●
20
20
40
40
MAX
UNITS
mA
mA
●
93
90
100
97
dB
dB
●
1.1
1.2
V
●
130
150
200
260
µA
µA
175
kHz
0.045
V/µs
5V REFERENCE: The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications
are at TA = 25°C. VS = 5V, 0V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
VREF
Feedback Sense Voltage
Voltage at Pin 1 with Pin 1 Connected
to Pin 8 (Note 6)
●
TC VREF
Reference Drift
(Note 4)
Feedback Current
Current into Pin 8
Line Regulation
Load Regulation
Reference Amplifier Gain
0 ≤ IREF ≤ 1mA, VREF = 200mV
VS = 1.2V to 5V
VS = 1.3V to 5V (Note 3)
MIN
TYP
MAX
UNITS
189
200
211
mV
●
30
100
ppm/°C
●
3.5
5.0
10
15
nA
nA
●
20
30
100
200
ppm/V
ppm/V
●
150
200
300
500
ppm/mA
ppm/mA
IREF = 0 to 1mA
VO = 0.2V to 3.5V
●
45
25
90
50
V/mV
V/mV
±5V OP AMP: The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are
at TA = 25°C. VS = ±5V; VCM = VOUT = 0V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
VOS
Input Offset Voltage
CONDITIONS
MIN
0°C ≤ TA ≤ 70°C
– 40°C ≤ TA ≤ 85°C
●
●
Input Offset Voltage Drift
0°C ≤ TA ≤ 85°C (Note 4)
●
VOS ADJ
Offset Voltage Adjust Range
Positive Adjust
Negative Adjust
●
●
IOS
Input Offset Current
IB
Input Bias Current
6
– 1.4
TYP
MAX
UNITS
0.3
0.5
1.5
1.9
2.1
mV
mV
mV
4.5
10.0
µV/°C
8
–2
mV
mV
●
0.2
0.6
nA
●
2.0
2.5
4.5
5.5
nA
nA
Input Noise Voltage
0.1Hz to 10Hz
1
µVP-P
en
Input Noise Voltage Density
f = 1kHz
50
nV/√Hz
in
Input Noise Current Density
f = 1kHz
0.05
pA/√Hz
RIN
Input Resistance
Differential
Common Mode, VCM = – 5V to 4V
Input Voltage Range
CMRR
Common Mode Rejection Ratio
●
7
●
–5
●
94
91
VCM = – 5V to 4V
35
9
MΩ
GΩ
4
115
110
V
dB
dB
3
LT1635
ELECTRICAL CHARACTERISTICS
±5V OP AMP: The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are
at TA = 25°C. VS = ±5V; VCM = VOUT = 0V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
AVOL
Large-Signal Voltage Gain
VO = – 4.5V to 4.5V, No Load
VO = – 4.5V to 4.5V, RL = 1.1k
VO = – 4.5V to 4.5V, RL = 500Ω
VO
Output Voltage Swing
VS = ±5V, No Load
VS = ±5V, ISINK = 5mA
VS = ±5V, ISINK = 10mA
ISC
Short-Circuit Current
VS = ±5V
PSRR
Power Supply Rejection Ratio
VS = ±1V to ±6V, VCM = VO = 0V
MIN
TYP
●
●
●
175
15
10
300
100
60
●
●
●
±4.975
±4.65
±4.5
±4.985
±4.75
±4.6
mV
mV
mV
±20
±40
mA
90
88
100
98
dB
dB
●
IS
Supply Current
135
160
●
MAX
UNITS
V/mV
V/mV
V/mV
215
280
µA
µA
GBW
Gain Bandwidth Product
f = 1kHz
175
kHz
SR
Slew Rate
AV = –1, RL = ∞
0.05
V/µs
±5V REFERENCE: The ● denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at TA = 25°C. VS = ±5V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
VREF
Feedback Sense Voltage
Voltage at Pin 1 with Pin 1 Connected
to Pin 8 (Note 6)
●
TC VREF
Reference Drift
(Note 4)
Feedback Current
Current into Pin 8
Line Regulation
Load Regulation
Reference Amplifier Gain
0 ≤ IREF ≤ 1mA, VREF = 200mV
VS = ±0.6V to ±5V
VS = ±0.65V to ±5V (Note 3)
TYP
MAX
UNITS
189
200
211
mV
●
40
120
ppm/°C
●
3.5
5.0
10
15
nA
nA
●
20
30
100
200
ppm /V
ppm/V
●
150
200
300
500
ppm/mA
ppm/mA
IREF = 0 to 1mA
VO = 0.2V to 8.5V
VS = 10V, 0V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be imparied.
Note 2: 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 3: The LT1635 op amp operates on a 1.2V supply over the full
industrial temperature range with an input common mode voltage of 0V to
0.2V. The minimum supply voltage for the reference to operate properly
over this temperature range is 1.3V.
4
MIN
●
45
25
90
50
V/mV
V/mV
Note 4: This parameter is not 100% tested. Temperature coefficient is
measured by dividing the change in output voltage by specified
temperature range.
Note 5: 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 6: If part is stored outside of the specified temperature range, the
output may shift due to hysteresis.
LT1635
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TYPICAL PERFOR A CE CHARACTERISTICS
Input Bias and Offset Currents
vs Temperature
160
140
–1
0
VS = 5V, 0V
VS = 5V, 0V
IOS
50
0
TA = 25°C
120
100
TA = 125°C
80
60
100
Input Bias Current
vs Common Mode Voltage
INPUT BIAS CURRENT (nA)
SUPPLY CURRENT (µA)
TA = – 55°C
180
OFFSET CURRENT (pA)
220
BIAS CURRENT (nA)
Supply Current vs Supply Voltage
200
Op Amp
6
7
4
5
8
SUPPLY VOLTAGE (V)
3
2
10
9
IB
–2
–3
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
80
4 5 6
TIME (SEC)
7
8
9
70
60
50
40
25
CHANGE IN INPUT OFFSET VOLTAGE (V)
PERCENT OF UNITS
15
10
5
10
100
FREQUENCY (Hz)
–4
–2
0
2
TCVOS (µV/°C)
4
0.3
0.2
0.1
1
1000
6
1635 G07
10
100
FREQUENCY (Hz)
1635 G06
200
140
0
120
– 200
TA = 125°C
– 400
TA = 25°C
– 600
TA = – 55°C
– 800
0
1
TOTAL SUPPLY VOLTAGE (V)
1000
Turn-On Drift
of Three Typical Units
–1000
–6
0.4
Minimum Supply Voltage
20
VS = ± 2.5V
TA = 25°C
1635 G05
Typical Distribution of Offset
Voltage Drift with Temperature
4
0
1
10
VS = 5V, 0V
0
2
3
1
COMMON MODE VOLTAGE (V)
Input Noise Current vs Frequency
VS = ± 2.5V
TA = 25°C
1635 G04
0
–4
0.5
CHANGE IN OFFSET VOLTAGE (µV)
3
–3
1635 G03
INPUT NOISE CURRENT DENSITY (pA/√Hz)
INPUT NOISE VOLTAGE DENSITY (nV/√Hz)
NOISE VOLTAGE (1µV/DIV)
2
TA = – 55°C
–5
–1
125
30
1
TA = 25°C
–2
Noise Voltage Density
vs Frequency
0.1Hz to 10Hz Noise Voltage
VS = ± 5V
TA = 25°C
TA = 125°C
1635 G02
1635 G01
0
–1
2
1635 G08
100
80
60
40
20
VS = ± 5V
TA = 25°C
0
0
1
7 8 9
4 5 6
2 3
TIME AFTER POWER ON (MINUTES)
10
1635 G09
5
LT1635
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TYPICAL PERFOR A CE CHARACTERISTICS
Gain Phase vs Frequency
VS = ± 2.5V
TA = 25°C
100
VS = ± 2.5V
TA = 25°C
50
PHASE
MARGIN
70°
80
60
40
20
30
120
50
140
PHASE
160
180
20
200
10
220
0
GAIN
– 10
240
–20
260
VS = ± 5V
RL = ∞
TA = 25°C
AV = 5
40
AV = 10
AV = 1
30
20
10
0
– 30
1
10
100
1k
10
10k 100k 1M
280
1000
100
FREQUENCY (kHz)
FREQUENCY (Hz)
350
GAIN-BANDWIDTH PRODUCT (kHz)
FALLING
SLEW RATE
0.07
0.06
RISING
SLEW RATE
0.04
– 50 – 25
50
25
75
0
TEMPERATURE (°C)
100
125
75
VS = 5V, 0V
70
300
PHASE MARGIN
250
65
200
60
150
1M
GAIN-BANDWIDTH
PRODUCT
100
–50 –25
50
25
0
75
TEMPERATURE (°C)
PHASE MARGIN (DEG)
0.08
TA = – 55°C
TA = 25°C
55
100
50
125
TA = 125°C
100k
0.1
1
10
100
1000
LOAD RESISTANCE TO GROUND (kΩ)
1635 G15
1635 G14
1635 G13
Large-Signal Transient Response
VS = ±5V
Shunt Gain
10000
Voltage Gain vs Load Resistance
VS = ± 2.5V
VS = ± 5V
0.09
100
1000
CAPACITIVE LOAD (pF)
1635 G12
Gain-Bandwidth Product and
Phase Margin vs Temperature
Slew Rate vs Temperature
0.05
10
1635 G11
1635 G10
0.10
0
VOLTAGE GAIN (V/V)
– 20
0.01 0.1
SLEW RATE (V/µs)
60
100
PHASE SHIFT (DEG)
VOLTAGE GAIN (dB)
40
VOLTAGE GAIN (dB)
Capacitive Load Handling
60
OVERSHOOT (%)
Voltage Gain vs Frequency
120
Op Amp
Large-Signal Transient Response
VS = 5V, 0V
0.5
IOUT = 20mA
0.3
0V
1V/DIV
0.4
2V/DIV
INPUT VOLTAGE CHANGE (mV)
TA = 25°C
+
+
0.2
VIN
0V
VOUT
–
IOUT
–
0.1
200µs/DIV
IOUT = 1mA
AV = 1, NO LOAD
INPUT 8VP-P
0
0
1
2
6
4
3
5
OUTPUT VOLTAGE (V)
7
8
1635 G16
6
1635 G17
100µs/DIV
AV = 1, NO LOAD
INPUT PULSE 0V TO 4V
1635 G18
LT1635
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TYPICAL PERFOR A CE CHARACTERISTICS
Output Saturation Voltage
vs Input Overdrive
Output Saturation Voltage
vs Load Current (Output Low)
1000
OUTPUT HIGH
12
10
8
6
4
OUTPUT LOW
2
5
0
10
20
25
15
INPUT OVERDRIVE (mV)
TA = 25°C
100
TA = 125°C
TA = – 55°C
10
1
0.001
30
0.01
0.1
1
SINKING LOAD CURRENT (mA)
Common Mode Range
vs Temperature
COMMON MODE REJECTION RATIO (dB)
COMMON MODE RANGE (V)
120
V + – 0.5
V+ – 1
V–
V – – 0.5
100
100
0.01
0.1
1
SOURCING LOAD CURRENT (mA)
60
40
20
10
100
1k
FREQUENCY (Hz)
1635 G21
120
VS = ± 2.5V
TA = 25°C
100
POSITIVE
SUPPLY
80
NEGATIVE
SUPPLY
60
40
20
0
100k
10k
10
Power Supply Rejection Ratio
vs Frequency
80
1
125
0.1
1
10
100
1k
FREQUENCY (Hz)
1635 G23
10k
100k
1635 G24
Small-Signal Transient Response
VS = ±5V
Output Impedance vs Frequency
Small-Signal Transient Response
VS = 5V, 0V
VS = ± 2.5V
TA = 25°C
AV = 100
AV = 10
10mV/DIV
OUTPUT IMPEDANCE (Ω)
0.01
0.001
10
VS = ±2.5V
TA = 25°C
1635 G22
1000
TA = – 55°C
0
50
25
75
0
TEMPERATURE (°C)
TA = 125°C
0.1
Common Mode Rejection Ratio
vs Frequency
V+
10000
TA = 25°C
1635 G20
1635 G19
V– – 1
– 50 – 25
VS = ± 2.5V
VOD = 30mV
AV = 1
100
0V
10mV/DIV
0
1
VS = ± 2.5V
VOD = 30mV
POWER SUPPLY REJECTION RATIO (dB)
14
Output Saturation Voltage
vs Load Current (Output High)
OUTPUT SATURATION VOLTAGE (V)
VS = ± 2.5V, NO LOAD
TA = 25°C
OUTPUT SATURATION VOLTAGE (mV)
OUTPUT SATURATION VOLTAGE (mV)
16
Op Amp
10
50µs/DIV
1
0.1
1
10
100
FREQUENCY (kHz)
1000
AV = 1
CL = 15pF
1635 G26
50µs/DIV
1635 G27
AV = 1
CL = 15pF
INPUT 50mV TO 100mV
1635 G25
7
LT1635
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TYPICAL PERFOR A CE CHARACTERISTICS
Typical Distribution
of Initial Accuracy
18
208
VS = 5V, 0V
TA = 25°C
200
VS = 5V, 0V
REFERENCE OUTPUT (mV)
14
12
10
8
6
206
TA = – 55°C
205
TA = 25°C
204
TA = 125°C
203
202
4
0
– 200
– 400
201
2
200
0
206
204
196
200
202
198
REFERENCE VOLTAGE (mV)
10
8
6
SUPPLY VOLTAGE (V)
2
12
4
205
1.5
OUTPUT SATURATION VOLTAGE (V)
VS = ±5V
204
203
202
Reference Amplifier Gain
120
VS = 5V, 0V
1.4
50
75
125
100
VS = 5V, 0V
TA = 25°C
100
1.3
80
1.2
1.1
TA = – 55°C
1.0
TA = 25°C
0.9
60
40
20
0.8
0
TA = 125°C
0.7
– 20
0.6
0.5
25
– 40
0
2
1
SOURCING CURRENT (mA)
TEMPERATURE (°C)
3
1
10
1635 G32
1635 G31
W
OUTPUT
REFERENCE
FEEDBACK
6
V+
8
7
BALANCE
INPUTS
–
5
–
OP AMP
3
REF AMP
+
+
200mV
REFERENCE
REFERENCE
OUTPUT
1635 BD
V–
8
1
+
4
1k 10k 100k
FREQUENCY (Hz)
100
1M
10M
1635 G33
BLOCK DIAGRA
2
4
1635 G30
Output Saturation
vs Load Current (Sourcing)
Reference Output vs Temperature
of Two Typical Units
0
2
1
3
SOURCING CURRENT (mA)
0
1635 G29
1635 G28
201
–50 –25
– 600
14
GAIN (dB)
0
194
REFERENCE OUTPUT (mV)
VS = 5V, 0V
TA = 25°C
207
16
PERCENT OF UNITS
Load Regulation
Line Regulation
REFERENCE CHANGE (ppm)
20
Reference
LT1635
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APPLICATIO S I FOR ATIO
The LT1635 is fully specified with V + = 5V, V – = 0V and
VCM = 2.5V. The op amp offset voltage is internally
trimmed to a minimum value at these supply voltages. A
unique feature of this device is that it operates from a
single 1.2V supply up to ±5V. A full set of specifications is
provided at ±5V supply voltages. The positive supply pin
of the LT1635 should be bypassed with a small capacitor
(about 0.1µF), as well as the negative supply pin when
using split supplies.
should be taken to keep the output from saturating. For
example, a 1mV input signal will cause the amplifier to set
up in its linear region in the gain 100 configuration as
shown in Figure 2a. However, 1mV is not enough to make
the amplifier function properly in the voltage follower mode
(Figure 2b).
99R
Op Amp
The LT1635 is fully specified for single supply operation,
i.e., when the negative supply is 0V. Input common mode
range of the op amp includes ground and the output
swings within a few millivolts of ground while sinking
current. The input stage of the op amp incorporates phase
reversal protection to prevent false outputs from occurring when the input is below the negative supply. Protective resistors have been included in the input leads so that
current does not become excessive when the inputs are
forced below the negative supply.
The op amp also includes an offset nulling feature, this is
accomplished by connecting the BALANCE pin (Pin 5) to
a variable voltage derived from the reference output. The
offset adjust range is asymmetrical, typically – 2mV to
8mV. At room temperature the input offset voltage of the
LT1635 is within the null range, thus the offset voltage can
be adjusted to zero. Figure 1 shows the standard offset
adjustment.
V+
2
–
3
+
–
–
LT1635
OP AMP
1mV
+
LT1635
OP AMP
100mV
1mV
+
OUTPUT
SATURATED
≈ 2mV
1635 F02
(a)
(b)
Figure 2. Gain 100 Amplifier and Voltage Follower
Distortion
There are two main contributors of distortion in op amps:
distortion caused by nonlinear common mode rejection
and output crossover distortion as the output transitions
from sourcing to sinking current. The common mode
rejection ratio of the LT1635 is very good, typically 110dB.
Therefore, as long as the input operates in normal common mode range, there will be very little common mode
induced distortion. Crossover distortion will increase as
the output load resistance decreases. For the lowest distortion, the LT1635 should be operated with the output
always sourcing current.
Reference
4
6
LT1635
1
5V
5V
R
8
5
VREF
R1
10k
V–
1635 F01
Figure 1. Standard Offset Adjustment
Output
The output voltage swing of the LT1635 is a function of
input overdrive as shown in the typical performance curves.
When monitoring voltages within 15mV of either rail, gain
The reference of the LT1635 consists of a 200mV precision
bandgap and a reference amplifier. As shown in the block
diagram, the 0.2V precision bandgap is referred to V – and
is internally connected to the noninverting input of the reference amplifier. This configuration offers great flexibility
in that the reference voltage can be amplified or the reference
amplifier can be used as a comparator. Unlike the op amp,
the output of the reference amplifier can only swing within
0.8V (typ) of the positive rail. To guarantee that the reference
amplifier does not saturate over the industrial temperature
range, the minimum operating supply should be 1.3V. The
reference amplifier can source 2mA of load current and can
sink 10µA over the industrial temperature range.
9
LT1635
U
TYPICAL APPLICATIO S
Low Voltage Regulator
Best Regulation
VIN > 6V
C1
0.01µF
VIN > 3.2V
R1
28k
–
3
+
7
6
LT1635
2
–
3
+
VOUT
5V
4
8
7
1
6
LT1635
R2
2k
2
VOUT
3V
4
R2
48k
+
8
1
R1
2k
OPTIONAL*
1635 TA04
*USE ELECTROLYTIC
OUTPUT CAPACITORS
1635 TA03
2-Terminal Current Regulator
+
2
–
3
+
IOUT =
Shunt Regulator
C1*
0.01µF
(R2 + R3)VREF
(R1)(R3)
7
R2
6
LT1635
VOUT = 1 + R2 VREF
R1
4
1
2
–
3
+
8
R1
( )
+
7
6
LT1635
R2
R3
–
R1
4
1
8
1635 TA05
–
*REQUIRED FOR CAPACITIVE LOADING
Negative Regulator
1635 TA06
6V Battery-Level Indicator
+
GROUND
R2
49.9k
1%
+
2
–
7
6
LT1635
3
+
4
C1
47µF
ELECT
R1
680k
VOUT
– 5V
R4
1.5k
R3
680k
2
–
3
+
D1
7
8
6
LT1635
1
Q1
2N3904
R2
12k
4
8
1
R1
2k
1%
–
VIN ≤ – 5.5V
1635 TA07
10
LED DIMS BELOW 7V
1635 TA08
LT1635
W
W
SI PLIFIED SCHE ATICS
Op Amp
+
7 V
Q21
Q28
C2
Q20
R1
6k
Q1
2
R2
6k
INPUTS
Q13
Q19
Q2
3
6 OUTPUT
Q15
Q26
Q7
Q4
300k
Q3
Q5
5
Q17
Q14
Q6
Q27
Q18
Q16
Q24
Q25
BALANCE
4 V–
+
1635 SSOA
C1
Reference
V+ 7
REF FB
8
1 REFOUT
× 16
×1
V– 4
1635 SSREF
U
PACKAGE DESCRIPTIO
N8 Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
0.300 – 0.325
(7.620 – 8.255)
0.009 – 0.015
(0.229 – 0.381)
(
+0.035
0.325 –0.015
8.255
+0.889
–0.381
)
0.045 – 0.065
(1.143 – 1.651)
0.400*
(10.160)
MAX
0.130 ± 0.005
(3.302 ± 0.127)
0.065
(1.651)
TYP
8
7
6
5
1
2
3
4
0.255 ± 0.015*
(6.477 ± 0.381)
0.100
(2.54)
BSC
0.125
(3.175) 0.020
MIN
(0.508)
MIN
0.018 ± 0.003
(0.457 ± 0.076)
N8 1098
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
11
LT1635
U
TYPICAL APPLICATIO
1A Shunt Battery Charger (IDARK = 230µA, VFLOAT = 14V)
100nF
1M
2A
3
1A
SOLAR
ARRAY
+
200mV
8
LT1635
REF
1
–
7V
2
7
+
220Ω
LT1635
OP AMP
–
6
12V
5A
GELCEL
TIP121
4
68k
1M
7.5Ω*
10W
2k
*DALE HLM-10
1635 TA09
U
PACKAGE DESCRIPTIO
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
8
0.053 – 0.069
(1.346 – 1.752)
0.014 – 0.019
(0.355 – 0.483)
TYP
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
6
5
0.004 – 0.010
(0.101 – 0.254)
0°– 8° TYP
0.016 – 0.050
(0.406 – 1.270)
7
0.050
(1.270)
BSC
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
SO8 1298
1
2
3
4
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1178/LT1179
Dual/Quad 17µA Max, Single Supply Precision Op Amps
70µV VOS Max and 2.5µV/°C Drift Max, 85kHz GBW, 0.04V/µs
Slew Rate, Input/Output Common Mode Includes Ground
LT1490A/LT1491A Dual/Quad Micropower Rail-to-Rail Input and Output Op Amps
Single Supply Input Range: – 0.4V to 44V, Micropower 50µA
Amplifier, Rail-to-Rail Input and Output, 200kHz GBW
LT2178/LT2179
Dual/Quad 17µA Max, Single Supply Precision Op Amps
SO-8 and 14-Lead Standard Pinout, 70µV VOS Max, 85kHz GBW
LT1078/LT1079
Dual/Quad Micropower, Single Supply Precision Op Amps
70µV VOS Max and 0.4µV/°C Drift, 200kHz GBW, 0.07V/µs Slew
Rate, Input/Output Common Mode Includes Ground
LT2078/LT2079
Dual/Quad Micropower, Single Supply Precision Op Amps
SO-8 and 14-Lead Standard Pinout, 70µV VOS Max, 200kHz GBW
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417● (408) 432-1900
FAX: (408) 434-0507 ● TELEX: 499-3977 ● www.linear.com
1635fa LT/TP 0901 1.5K REV A • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 1997
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