LTC6001U
P-1
General Description
The LTC6001U of single-channel operational amplifiers is specifically designed for
general-purpose cost-sensitive systems and applications. Featuring rail-to-rail input
and output (RRIO) swings, and low quiescent current (typical 75 µA) combined with a
wide bandwidth (1.5 MHz) and very low noise (25 nV/√Hz at 1 kHz) makes this family very
attractive for a variety of battery-powered applications that require a good balance
between cost and performance, such as audio outputs, consumer electronics, smoke
detectors, portable medical devices and white goods. The low input bias current
supports these amplifiers to be used in applications with mega-ohm source impedances.
The robust design of the LTC6001U amplifiers provides ease-of-use to the circuit
designer: unity-gain stability with capacitive loads of up to 500 pF, integrated RF/EMI
rejection filter, no phase reversal in overdrive conditions, and high electro-static
discharge (ESD) protection (5-kV HBM). The LTC6001 amplifiers are optimized for
operation at voltages as low as +1.8 V (±0.9 V) and up to +5.5 V (±2.75 V) at the
temperature range of 0 ℃ to 70 ℃, and operation at voltages from +2.0 V (±1.0 V) to +5.5
V (±2.75 V) over the extended temperature range of −40 ℃ to +125 ℃.
The LTC6001U (single) is available in both SOT23-5L and SC70-5L packages.
Features and Benefits
Precision Amplifiers for Cost-Sensitive Systems
Low Noise: 25 nV/√Hz at 1 kHz
Low Input Offset Voltage: 0.5 mV
1.5 MHz GBW for Unity-Gain Stable
Micro-Power: 75 μA Supply Current Per Amplifier
Single 1.8 V to 5.5 V Supply Voltage Range at 0 ℃ to 70 ℃
Rail-to-Rail Input and Output
Internal RF/EMI Filter
Extended Temperature Range: −40℃ to +125℃
Applications
Battery-Powered Instruments:
– Consumer, Industrial, Medical, Notebooks
Audio Outputs
Wireless Sensors:
– Home Security, Remote Sensing, Wireless Metering
Sensor Signal Conditioning:
– Sensor Interfaces, Loop-Powered, Active Filters
Pin Configurations (Top View)
LTC6001U
SOT23-5L / SC70-5L
+IN
1
–VS
2
–IN
3
5
+VS
4
OUT
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-2
Pin Description
Symbol
Description
–IN
Inverting input of the amplifier. The voltage range is from (VS– – 0.1V) to (VS+ + 0.1V).
+IN
Non-inverting input of the amplifier. This pin has the same voltage range as –IN.
+VS
Positive power supply.
–VS
Negative power supply.
OUT
Amplifier output.
Ordering Information
Type Number
Package Name
Package Quantity
Marking Code (1)
LTC6001UXT5/R6
SOT23-5L
Tape and Reel, 3 000
AG3xx, 321, 321I
LTC6001UXC5/R6
SC70-5L
Tape and Reel, 3 000
AG3xx, 321
(1) There may be multiple device markings, a varied marking character of “x” , or additional marking, which relates to the
logo, the lot trace code information, or the environmental category on the device.
Limiting Value
In accordance with the Absolute Maximum Rating System (IEC 60134).
Parameter
Absolute Maximum Rating
Supply Voltage, VS+ to VS–
10.0 V
Signal Input Terminals: Voltage, Current
VS– – 0.5 V to VS+ + 0.5 V, ±20 mA
Output Short-Circuit
Continuous
Storage Temperature Range, Tstg
–65 ℃ to +150 ℃
Junction Temperature, TJ
150 ℃
Lead Temperature Range (Soldering 10 sec)
260 ℃
ESD Rating
Parameter
Electrostatic
Discharge
Voltage
Item
Value
Human body model (HBM), per MIL-STD-883J / Method 3015.9 (1)
±5 000
Charged device model (CDM), per ESDA/JEDEC JS-002-2014
±2 000
Machine model (MM), per JESD22-A115C
(2)
Unit
V
±250
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
Manufacturing with less than 500-V HBM is possible if necessary precautions are taken.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
Manufacturing with less than 250-V CDM is possible if necessary precautions are taken.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-3
Electrical Characteristics
VS = 5.0V, TA = +25℃, VCM = VS /2, VO = VS /2, and RL = 10kΩ connected to VS /2, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA = −40 to +125 ℃.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
OFFSET VOLTAGE
±0.5
VOS
Input offset voltage
VOS TC
Offset voltage drift
TA = −40 to +125 ℃
Power supply
rejection ratio
VS = 2.0 to 5.5 V, VCM < VS+ − 2V
80
TA = −40 to +125 ℃
75
PSRR
TA = −40 to +125 ℃
±2.5
±2.8
±1
3
110
mV
μV/℃
dB
INPUT BIAS CURRENT
1
IB
Input bias current
IOS
Input offset current
TA = +85 ℃
150
TA = +125 ℃
500
pA
1
pA
μVP-P
NOISE
Vn
Input voltage noise
f = 0.1 to 10 Hz
5.6
en
Input voltage noise
density
f = 10 kHz
22
f = 1 kHz
25
In
Input current noise
density
f = 1 kHz
5
nV/√Hz
fA/√Hz
INPUT VOLTAGE
VCM
CMRR
Common-mode
voltage range
Common-mode
rejection ratio
VS––0.1
VS = 5.5 V, VCM = −0.1 to 5.6 V
70
VCM = 0 to 5.3 V, TA = −40 to +125 ℃
65
VS = 2.0 V, VCM = −0.1 to 2.1 V
65
VCM = 0 to 1.8 V, TA = −40 to +125 ℃
60
VS++0.1
V
83
77
dB
INPUT IMPEDANCE
CIN
Input capacitance
Differential
2.0
Common mode
3.5
pF
OPEN-LOOP GAIN
AVOL
Open-loop voltage
gain
RL = 25 kΩ, VO = 0.05 to 3.5 V
90
TA = −40 to +125 ℃
85
RL = 2 kΩ, VO = 0.15 to 3.5 V
85
TA = −40 to +125 ℃
80
105
100
dB
FREQUENCY RESPONSE
GBW
Gain bandwidth
product
SR
Slew rate
G = +1, CL = 100 pF, VO = 1.5 to 3.5 V
THD+N
Total harmonic
distortion + noise
G = +1, f = 1 kHz, VO = 1 VRMS
tS
Settling time
tOR
Overload recovery
time
1.5
MHz
1.2
V/μs
0.002
%
To 0.1%, G = +1, 1V step
1.2
To 0.01%, G = +1, 1V step
1.5
To 0.1%, VIN * Gain > VS
2
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
μs
μs
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-4
Electrical Characteristics (continued)
VS = 5.0V, TA = +25℃, VCM = VS /2, VO = VS /2, and RL = 10kΩ connected to VS /2, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA = −40 to +125 ℃.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
OUTPUT
VOH
High output voltage
swing
RL = 25 kΩ
VS+–9
VS+–5
RL = 2 kΩ
VS+–95
VS+–63
VOL
Low output voltage
swing
RL = 25 kΩ
VS–+3.5
VS–+6
RL = 2 kΩ
VS–+43
VS–+65
ISC
Short-circuit current
Source current through 10Ω
45
Sink current through 10Ω
55
mV
mV
mA
POWER SUPPLY
VS
Operating supply
voltage
IQ
Quiescent current
(per amplifier)
TA = 0 to +70 ℃
1.8
5.5
TA = −40 to +125 ℃
2.0
5.5
75
TA = −40 to +125 ℃
125
160
V
μA
THERMAL CHARACTERISTICS
TA
Operating
temperature range
θJA
Package Thermal
Resistance
–40
+125
SC70-5L
333
SOT23-5L
190
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
℃
℃/W
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-5
Typical Performance Characteristics
At TA = +25℃, VCM = VS /2, and RL = 10kΩ connected to VS /2, unless otherwise noted.
Distribution (Units)
900
800
1,000
VCM = –VS
5,000 Samples
Voltage Noise (nV/√Hz)
1000
700
100
600
500
400
300
200
100
0
10
1
1
100
Offset Voltage (mV)
60
40
20
0
-20
-40
10
100
1k
10k
100k
1M
140
120
100
CMRR (dB)
AOL (dB)
80
140
120
100
80
60
40
20
0
-20
-40
-60
-80
10M
Phase (deg)
100
80
60
40
20
0
1
100
Frequency (Hz)
10k
1M
Frequency (Hz)
Open-loop Gain and Phase as a function of
Frequency.
Common-mode Rejection Ratio as a function of
Frequency.
125
140
Quiescent Current (μA)
120
100
PSRR (dB)
1M
Input Voltage Noise Spectral Density as a function of
Frequency.
Offset Voltage Production Distribution
120
10k
Frequency (Hz)
80
60
40
20
100
75
50
25
0
0
1
100
10k
1M
1.5
2.5
3
3.5
4
4.5
5
5.5
Supply Voltage (V)
Frequency (Hz)
Power Supply Rejection Ratio as a function of
Frequency.
2
Quiescent Current as a function of Supply Voltage.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-6
Typical Performance Characteristics (continued)
At TA = +25℃, VCM = VS /2, and RL = 10kΩ connected to VS /2, unless otherwise noted.
5
Sourcing Current
4
100
Output Voltage (V)
Quiescent Current (μA)
120
80
60
40
–40℃
3
+125℃
+25℃
2
1
Sinking Current
0
-50
-25
0
25
50
75
100
125
0
10
Temperature (℃)
30
40
50
60
70
Output Current (mA)
Output Voltage Swing as a function of Output
Current.
Quiescent Current as a function of Temperature.
80
60
Short-circuit Current (mA)
Short-circuit Current (mA)
20
60
–ISC
40
20
+ISC
0
–ISC
50
40
+ISC
30
20
2
2.5
3
3.5
4
4.5
5
5.5
-50
0
25
50
75
100
125
Temperature (℃)
Supply Voltage (V)
Short-circuit Current as a function of Supply
Voltage.
-25
Short-circuit Current as a function of Temperature.
CL=100pF
1V/div
25mV/div
CL=100pF
5μs/div
Large Signal Step Response.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
2μs/div
Small Signal Step Response.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
P-7
LTC6001U
Application Notes
The LTC6001U is a family of low-power, rail-to-rail
input and output operational amplifiers specifically
designed for portable applications. These devices
operate from 1.8 V to 5.5 V at the temperature range
of 0 ℃ to 70 ℃, are unity-gain stable, and suitable
for a wide range of general-purpose applications.
The class AB output stage is capable of driving ≤ 10kΩ loads connected to any point between VS+ and
ground. The input common-mode voltage range
includes both rails, and allows the LTC6001U family
to be used in virtually any single-supply application.
Rail-to-rail input and output swing significantly
increases dynamic range, especially in low-supply
applications, and makes them ideal for driving
sampling analog-to-digital converters (ADCs).
The LTC6001U features 1.5-MHz bandwidth and 1.2V/μs slew rate with only 75-μA supply current per
amplifier, providing good ac performance at very low
power consumption. DC applications are also well
served with a low input noise voltage of 25-nV/√Hz
at 1-kHz, low input bias current, and an input offset
voltage of 0.5-mV typically. The typical offset voltage
drift is 1-μV/℃, over the full temperature range the
input offset voltage changes only 100-μV (0.5-mV to
0.6-mV).
OPERATING VOLTAGE
The LTC6001U family is optimized for operation at
voltages as low as +1.8 V (±0.9 V) and up to +5.5 V
(±2.75 V) at the temperature range of 0 ℃ to 70 ℃,
and fully specified and ensured for operation from
2.0 V to 5.5 V (±1.0 V to ±2.75 V). In addition, many
specifications apply from –40 ℃ to +125 ℃.
Parameters that vary significantly with operating
voltages or temperature are illustrated in the Typical
Characteristics graphs.
NOTE: Supply voltages (VS+ to VS–) higher than +10 V
can permanently damage the device.
RAIL-TO-RAIL INPUT
The input common-mode voltage range of the
LTC6001U series extends 100-mV beyond the
negative and positive supply rails. This performance
is achieved with a complementary input stage: an Nchannel input differential pair in parallel with a Pchannel differential pair. The N-channel pair is active
for input voltages close to the positive rail, typically
VS+–1.4 V to the positive supply, whereas the Pchannel pair is active for inputs from 100-mV below
the negative supply to approximately VS+–1.4 V. There
is a small transition region, typically VS+–1.2 V to VS+–1
V, in which both pairs are on. This 200-mV transition
region can vary up to 200-mV with process variation.
Thus, the transition region (both stages on) can range
from VS+–1.4 V to VS+–1.2 V on the low end, up to VS+–1
V to VS+–0.8 V on the high end. Within this transition
region, PSRR, CMRR, offset voltage, offset drift, and
THD can be degraded compared to device operation
outside this region.
The typical input bias current of the LTC6001U during
normal operation is approximately 1-pA. In
overdriven conditions, the bias current can increase
significantly. The most common cause of an
overdriven condition occurs when the operational
amplifier is outside of the linear range of operation.
When the output of the operational amplifier is driven
to one of the supply rails, the feedback loop
requirements cannot be satisfied and a differential
input voltage develops across the input pins. This
differential input voltage results in activation of
parasitic diodes inside the front-end input chopping
switches that combine with electromagnetic
interference (EMI) filter resistors to create the
equivalent circuit. Notice that the input bias current
remains within specification in the linear region.
INPUT EMI FILTER AND CLAMP CIRCUIT
Figure 1 shows the input EMI filter and clamp circuit.
The LTC6001U op-amps have internal ESD protection
diodes (D1, D2, D3, and D4) that are connected
between the inputs and each supply rail. These
diodes protect the input transistors in the event of
electrostatic discharge and are reverse biased
during normal operation. This protection scheme
allows voltages as high as approximately 500-mV
beyond the rails to be applied at the input of either
terminal without causing permanent damage. These
ESD protection current-steering diodes also provide
in-circuit, input overdrive protection, as long as the
current is limited to 20-mA as stated in the Absolute
Maximum Ratings.
VS+
D1
RS1
5kΩ
IN+
D2
D3
CCM1
RS2 CDM
5kΩ
IN–
D4
CCM2
VS–
Figure 1. Input EMI Filter and Clamp Circuit
Operational amplifiers vary in susceptibility to EMI. If
conducted EMI enters the operational amplifier, the
dc offset at the amplifier output can shift from its
nominal value when EMI is present. This shift is a
result of signal rectification associated with the
internal semiconductor junctions. Although all
operational amplifier pin functions can be affected by
EMI, the input pins are likely to be the most
susceptible. The EMI filter of the LTC6001 family is
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-8
Application Notes (continued)
composed of two 5-kΩ input series resistors (RS1 and
RS2), two common-mode capacitors (CCM1 and CCM2),
and a differential capacitor (CDM). These RC networks
set the −3 dB low-pass cutoff frequencies at 35-MHz
for common-mode signals, and at 22-MHz for
differential signals.
RAIL-TO-RAIL OUTPUT
Designed as a micro-power, low-noise operational
amplifier, the LTC6001U delivers a robust output
drive capability. A class AB output stage with
common-source transistors is used to achieve full
rail-to-rail output swing capability. For resistive
loads up to 25-kΩ, the output swings typically to
within 5-mV of either supply rail regardless of the
power-supply voltage applied. Different load
conditions change the ability of the amplifier to swing
close to the rails. For resistive loads up to 2-kΩ, the
output swings typically to within 63-mV of the
positive supply rail and within 43-mV of the negative
supply rail.
provides the DC accuracy by connecting the inverting
signal with the output.
The CF and RISO serve to counteract the loss of phase
margin by feeding the high frequency component of
the output signal back to the amplifier’s inverting
input, thereby preserving phase margin in the overall
feedback loop.
For no-buffer configuration, there are two others
ways to increase the phase margin: (a) by increasing
the amplifier’s gain, or (b) by placing a capacitor in
parallel with the feedback resistor to counteract the
parasitic capacitance associated with inverting node.
CF
RISO
VIN
CL
The LTC6001U family can safely drive capacitive loads
of up to 500-pF in any configuration. As with most
amplifiers, driving larger capacitive loads than
specified may cause excessive overshoot and ringing,
or even oscillation. A heavy capacitive load reduces
the phase margin and causes the amplifier frequency
response to peak. Peaking corresponds to overshooting or ringing in the time domain. Therefore, it
is recommended that external compensation be used
if the LTC6001U op-amps must drive a load exceeding
500-pF. This compensation is particularly important
in the unity-gain configuration, which is the worst
case for stability.
A quick and easy way to stabilize the op-amp for
capacitive load drive is by adding a series resistor,
RISO, between the amplifier output terminal and the
load capacitance, as shown in Figure 2. RISO isolates
the amplifier output and feedback network from the
capacitive load. The bigger the RISO resistor value, the
more stable VOUT will be. Note that this method
results in a loss of gain accuracy because RISO forms
a voltage divider with the RL.
RISO
VOUT
LTC6001
CAPACITIVE LOAD AND STABILITY
LTC6001
RF
VOUT
VIN
CL
Figure 2. Indirectly Driving Heavy Capacitive Load
An improvement circuit is shown in Figure 3. It
provides DC accuracy as well as AC stability. The RF
RL
Figure 3. Indirectly Driving Heavy Capacitive Load
with DC Accuracy
OVERLOAD RECOVERY
Overload recovery is defined as the time required for
the operational amplifier output to recover from a
saturated state to a linear state. The output devices
of the operational amplifier enter a saturation region
when the output voltage exceeds the rated operating
voltage, either because of the high input voltage or
the high gain. After the device enters the saturation
region, the charge carriers in the output devices
require time to return back to the linear state. After
the charge carriers return back to the linear state,
the device begins to slew at the specified slew rate.
Thus, the propagation delay in case of an overload
condition is the sum of the overload recovery time
and the slew time. The overload recovery time for
the LTC6001U family is approximately 2-μs.
EMI REJECTION RATIO
Circuit performance is often adversely affected by
high frequency EMI. When the signal strength is low
and transmission lines are long, an op-amp must
accurately amplify the input signals. However, all opamp pins — the non-inverting input, inverting input,
positive supply, negative supply, and output pins —
are susceptible to EMI signals. These high frequency
signals are coupled into an op-amp by various
means, such as conduction, near field radiation, or
far field radiation. For example, wires and printed
circuit board (PCB) traces can act as antennas and
pick up high frequency EMI signals.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-9
Application Notes (continued)
Amplifiers do not amplify EMI or RF signals due to
their relatively low bandwidth. However, due to the
nonlinearities of the input devices, op-amps can
rectify these out of band signals. When these high
frequency signals are rectified, they appear as a dc
offset at the output.
The LTC6001U op-amps have integrated EMI filters at
their input stage. A mathematical method of
measuring EMIRR is defined as follows:
EMIRR = 20 log (VIN_PEAK / ΔVOS)
resulting in a thermal voltage error.
This thermocouple error can be reduced by using
dummy components to match the thermoelectric
error source. Placing the dummy component as
close as possible to its partner ensures both
Seebeck voltages are equal, thus canceling the
thermocouple error. Maintaining a constant ambient
temperature on the circuit board further reduces this
error. The use of a ground plane helps distribute heat
throughout the board and reduces EMI noise pickup.
INPUT-TO-OUTPUT COUPLING
To minimize capacitive coupling, the input and output
signal traces should not be parallel. This helps
reduce unwanted positive feedback.
MAXIMIZING PERFORMANCE THROUGH PROPER
LAYOUT
To achieve the maximum performance of the
extremely high input impedance and low offset
voltage of the LTC6001U op-amps, care is needed in
laying out the circuit board. The PCB surface must
remain clean and free of moisture to avoid leakage
currents between adjacent traces. Surface coating of
the circuit board reduces surface moisture and
provides a humidity barrier, reducing parasitic
resistance on the board. The use of guard rings
around the amplifier inputs further reduces leakage
currents. Figure 4 shows proper guard ring
configuration and the top view of a surface-mount
layout. The guard ring does not need to be a specific
width, but it should form a continuous loop around
both inputs. By setting the guard ring voltage equal to
the voltage at the non-inverting input, parasitic
capacitance is minimized as well. For further
reduction of leakage currents, components can be
mounted to the PCB using Teflon standoff insulators.
Guard
Ring
+IN
–IN
+VS
Figure 4. Use a guard ring around sensitive pins
Other potential sources of offset error are
thermoelectric voltages on the circuit board. This
voltage, also called Seebeck voltage, occurs at the
junction of two dissimilar metals and is proportional
to the temperature of the junction. The most common
metallic junctions on a circuit board are solder-toboard trace and solder-to-component lead. If the
temperature of the PCB at one end of the component
is different from the temperature at the other end,
the resulting Seebeck voltages are not equal,
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-10
Typical Application Circuits
DIFFERENTIAL AMPLIFIER
eliminates expansive low-leakage cables that that is
required to connect a pH probe (general purpose
combination pH probes, e.g Corning 476540) to metering
ICs such as ADC, AFE and/or MCU. A LTC6001U op-amp and
a lithium battery are housed in the probe assembly. A
conventional low-cost coaxial cable can be used to carry
the op-amp’s output signal to subsequent ICs for pH
reading.
R2
R1
Vn
LTC6001
VOUT
Vp
R3
MOTOR PHASE CURRENT SENSING AMPLIFIER
R4
VREF
Figure 5. Differential Amplifier
The circuit shown in Figure 5 performs the difference
function. If the resistors ratios are equal R4/R3 = R2/R1, then:
VOUT = (Vp – Vn) × R2/R1 + VREF
INSTRUMENTATION AMPLIFIER
RG
VREF
R1
R2
R2
R1
LTC6001
LTC6001
VOUT
V1
V2
VOUT =(V1 V2 )(1
R1 2 R1
) VREF
R2 RG
The current sensing amplification shown in Figure 8 has a
slew rate of 2πfVPP for the output of sine wave signal, and
has a slew rate of 2fVPP for the output of triangular wave
signal. In most of motor control systems, the PWM
frequency is at 10 kHz to 20 kHz, and one cycle time is 100
μs for a 10 kHz of PWM frequency. In current shunt
monitoring for a motor phase, the phase current is
converted to a phase voltage signal for ADC sampling. This
sampling voltage signal must be settled before entering the
ADC. As the Figure 8 shown, the total settling time of a
current shunt monitor circuit includes: the rising edge delay
time (tSR) due to the op-amp’s slew rate, and the
measurement settling time (tSET). For a 3-shunt solution in
motor phase current sensing, if the smaller duty cycle of
the PWM is defined at 45% (In fact, the phase with minimum
PWM duty cycle, such as 5%, is not detected current directly,
and it can be calculated from the other two phase currents),
and the tSR is required at 20% of a total time window for a
phase current monitoring, in case of a 3.3 V motor control
system (3.3 V MCU with 12-bit ADC), the op-amp’s slew rate
should be more than:
3.3V / (100μs× 45% × 20%) = 0.37 V/μs
At the same time, the op-amp’s bandwidth should be much
greater than the PWM frequency, like 10 time at least.
Figure 6. Instrumentation Amplifier
The LTC6001U family is well suited for conditioning sensor
signals in battery-powered applications. Figure 6 shows a
two op-amp instrumentation amplifier, using the LTC6001
op-amps. The circuit works well for applications requiring
rejection of common-mode noise at higher gains. The
reference voltage (VREF) is supplied by a low-impedance
source. In single voltage supply applications, the VREF is
typically VS/2.
tSR
VBUS
tSET
High side
switch
tSR – Time delay due to op-amp slew rate
tSET – Measurement settling time
tSMP – Sampling time window
To Motor Phase
VM
Low side
switch
BUFFERED CHEMICAL SENSORS
tSMP
R2
R1
RSHUNT
Coax
LTC6001
R3
R4
LTC6001
R1
10MΩ
3V
C1
To ADC,
AFE or MCU
R5
C2
Filter
pH
PROBE
Offset
Amplification
Figure 8. Current Shunt Monitor Circuit
R2
10MΩ
All components contained within the pH probe
Figure 7. Buffered pH Probe
The LTC6001U family has input bias current in the pA range.
This is ideal in buffering high impedance chemical sensors,
such as pH probes. As an example, the circuit in Figure 7
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
To MCU
ADC pin
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-11
Tape and Reel Information
REEL DIMENSIONS
TAPE DIMENSIONS
K0
P1
B0 W
Reel
Diameter
A0
Cavity
A0
B0
K0
W
P1
Reel
Width (W1)
Dimension designed to accommodate the component width
Dimension designed to accommodate the component length
Dimension designed to accommodate the component thickness
Overall width of the carrier tape
Pitch between successive cavity centers
QUADRANT ASSIGNMENTS FOR PIN 1 ORIETATION IN TAPE
Sprocket Holes
Q1
Q2
Q1
Q2
Q3
Q4
Q3
Q4
User Direction of Feed
Pocket Quadrants
* All dimensions are nominal
Device
LTC6001UXT5/R6
Package
Pins
Type
SOT23
5
SPQ
3 000
Reel
Reel
Diameter Width W1
(mm)
(mm)
178
9.0
A0
(mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
(mm)
Pin 1
Quadrant
3.3
3.2
1.5
4.0
8.0
Q3
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-12
Package Outlines
DIMENSIONS, SOT23-5L
A2
A
A1
D
e1
Symbol
A
A1
A2
b
c
D
E1
E
e
e1
L
L1
θ
θ
L
E
E1
L1
e
b
Dimensions
In Millimeters
Min
Max
1.25
0.04
0.10
1.00
1.20
0.33
0.41
0.15
0.19
2.820
3.02
1.50
1.70
2.60
3.00
0.95 BSC
1.90 BSC
0.60 REF
0.30
0.60
0°
8°
Dimensions
In Inches
Min
Max
0.049
0.002
0.004
0.039
0.047
0.013
0.016
0.006
0.007
0.111
0.119
0.059
0.067
0.102
0.118
0.037 BSC
0.075 BSC
0.024 REF
0.012
0.024
0°
8°
c
RECOMMENDED SOLDERING FOOTPRINT, SOT23-5L
1.0
0.039
0.95
0.037
0.95
0.037
0.7
0.028
2.4
0.094
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
mm
( inches
)
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
LTC6001U
P-13
Package Outlines (continued)
DIMENSIONS, SC70-5L (SOT353)
A2
A
Symbol
A1
D
e1
A
A1
A2
b
C
D
E
E1
e
e1
L
L1
θ
θ
e
L
E1
E
L1
b
Dimensions
In Millimeters
Min
Max
0.90
1.10
0.00
0.10
0.90
1.00
0.15
0.35
0.08
0.15
2.00
2.20
1.15
1.35
2.15
2.45
0.65 typ.
1.20
1.40
0.525 ref.
0.26
0.46
0°
8°
C
RECOMMENDED SOLDERING FOOTPRINT, SC70-5L (SOT353)
0.50
0.0197
0.65
0.0256
0.65
0.0256
0.40
0.0157
1.9
0.0748
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
mm
( inches
)
Dimensions
In Inches
Min
Max
0.035
0.043
0.000
0.004
0.035
0.039
0.006
0.014
0.003
0.006
0.079
0.087
0.045
0.053
0.085
0.096
0.026 typ.
0.047
0.055
0.021 ref.
0.010
0.018
0°
8°
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
P-14
LTC6001U
IMPORTANT NOTICE
Linearin is a global fabless semiconductor company specializing in advanced high-performance highquality analog/mixed-signal IC products and sensor solutions. The company is devoted to the innovation
of high performance, analog-intensive sensor front-end products and modular sensing solutions, applied
in multi-market of medical & wearable devices, smart home, sensing of IoT, and intelligent industrial &
smart factory (industrie 4.0). Linearin’s product families include widely-used standard catalog products,
solution-based application specific standard products (ASSPs) and sensing solutions that help customers
achieve faster time-to-market products. Go to http://www.linearin.com for a complete list of Linearin
product families.
For additional product information, or full datasheet, please contact with the Linearin’s Sales Department
or Representatives.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33U.1 — Data Sheet
Micro-Power 1.5MHz, Low-Noise, RRIO, 1.8V CMOS Amplifiers
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