GS8721/8722/8724
11MHZ CMOS Rail-to-Rail IO Opamps
Features
•
Single-Supply Operation from +2.1V ~ +5.5V
•
Quiescent Current: 1.1mA per Amplifier (Typ.)
•
Rail-to-Rail Input / Output
•
Operating Temperature: -40°C ~ +125°C
•
Gain-Bandwidth Product: 11MHz (Typ.)
•
Small Package:
•
Low Input Bias Current: 1pA (Typ.)
GS8721 Available in SOT23-5, SOP-8 and SC70-5
•
Low Offset Voltage: 3.5mV (Max.)
Packages
•
High Slew Rate: 9V/µs
GS8722 Available in SOP-8 and MSOP-8 Packages
•
Settling Time to 0.1% with 2V Step: 0.3µs
GS8724 Available in SOP-14 and TSSOP-14 Packages
•
Low Noise : 8nV/ Hz @10kHz
GS8721N Available in SOT23-6 and SC70-6 Packages
General Description
The GS872X have a high gain-bandwidth product of 11MHz, a slew rate of 9V/
μs, and a quiescent current of 1.1mA per
amplifier at 5V. The GS872X are designed to provide optimal performance in low voltage and low noise systems. They provide
rail-to-rail output swing into heavy loads. The input common mode voltage range includes ground, and the maximum input
offset voltage is 3.5mV for GS872X. They are specified over the extended industrial temperature range (-40
℃ to +125℃). The
operating range is from 2.1V to 5.5V. The GS8721 single is available in Green SC70-5, SOT23-5 and SOP-8 packages. The
GS8722 dual is available in Green SOP-8 and MSOP-8 packages. The GS8724 Quad is available in Green SOP-14 and
TSSOP-14 packages.
Applications
•
Sensors
•
Audio
•
Active Filters
•
Handheld Test Equipment
•
Cellular and Cordless Phones
•
Battery-Powered Instrumentation
•
Laptops and PDAs
•
A/D Converters
Pin Configuration
Figure 1. Pin Assignment Diagram
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GS8721/8722/8724
Absolute Maximum Ratings
Condition
Min
Max
-0.5V
+7.5V
Analog Input Voltage (IN+ or IN-)
Vss-0.5V
VDD+0.5V
PDB Input Voltage
Vss-0.5V
+7V
-40°C
+125°C
Power Supply Voltage (VDD to Vss)
Operating Temperature Range
Junction Temperature
+160°C
Storage Temperature Range
-55°C
Lead Temperature (soldering, 10sec)
Package Thermal Resistance (TA=+25
+150°C
+260°C
℃)
SOP-8, θJA
125°C/W
MSOP-8, θJA
216°C/W
SOT23-5, θJA
190°C/W
SOT23-6, θJA
190°C/W
SC70-5, θJA
333°C/W
ESD Susceptibility
HBM
8KV
MM
400V
Note: Stress greater than those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at these or any other conditions outside those indicated in the operational
sections of this specification are not implied. Exposure to absolute maximum rating conditions for extended periods may affect
reliability.
Package/Ordering Information
MODEL
GS8721
CHANNEL
Single
GS8722
Dual
GS8724
Quad
V1
PACKAGE
PACKAGE
MARKING
DESCRIPTION
OPTION
INFORMATION
GS8721-CR
SC70-5
Tape and Reel,3000
8721
GS8721-TR
SOT23-5
Tape and Reel,3000
8721
GS8721-SR
SOP-8
Tape and Reel,4000
GS8721
GS8722-SR
SOP-8
Tape and Reel,4000
GS8722
GS8722-MR
MSOP-8
Tape and Reel,3000
GS8722
GS8724-TR
TSSOP-14
Tape and Reel,3000
GS8724
GS8724-SR
SOP-14
Tape and Reel,2500
GS8724
ORDER NUMBER
2/17
GS8721/8722/8724
Electrical Characteristics
(At Vs=5V, TA = +25
℃, V
CM
= VS/2, RL = 600
Ω, unless otherwise noted.)
GS8721/2/4
MIN/MAX OVER TEMPERATURE
TYP
PARAMETER
CONDITIONS
+25
℃
℃
℃ to
70℃
3.5
3.9
+25
0
℃
to 85℃
℃ to
125℃
UNITS
4.3
4.6
mV
MAX
-40
-40
MIN /
MAX
INPUT CHARACTERISTICS
Input Offset Voltage (VOS)
0.8
Input Bias Current (IB)
1
pA
TYP
Input Offset Current (IOS)
1
pA
TYP
-0.1 to
V
TYP
Input Common Mode Voltage Range (VCM)
VS = 5.5V
+5.6
Common Mode Rejection Ratio (CMRR)
Open-Loop Voltage Gain (AOL)
VS = 5.5V, VCM = -0.1V to 4V
82
VS = 5.5V, VCM = -0.1V to 5.6V
75
RL = 600Ω,VO = 0.15V to 4.85V
90
RL = 10kΩ,VO = 0.05V to 4.95V
108
Input Offset Voltage Drift (∆VOS/∆T)
65
80
64
76
64
75
63
68
dB
MIN
dB
MIN
dB
MIN
dB
MIN
℃
2.4
µV/
TYP
RL = 600Ω
0.1
V
TYP
RL = 10kΩ
0.015
V
TYP
mA
MIN
7.5
Ω
TYP
Turn-On Time
1.1
µs
TYP
Turn-Off Time
0.3
µs
TYP
OUTPUT CHARACTERISTICS
Output Voltage Swing from Rail
Output Current (IOUT)
Closed-Loop Output Impedance
70
f = 100kHz, G = 1
55
45
42
38
POWER-DOWN DISABLE
DISABLE Voltage-Off
0.8
V
MAX
DISABLE Voltage-On
2
V
MIN
POWER SUPPLY
Operating Voltage Range
Power Supply Rejection Ratio (PSRR)
2.1
2.1
2.1
2.1
V
MIN
5.5
5.5
5.5
5.5
V
MAX
VS = +2.5V to +5.5V
VCM = (-VS) + 0.5V
Quiescent Current/Amplifier (IQ)
V1
91
74
72
72
68
dB
MIN
1.1
1.5
1.65
1.7
1.85
mA
MAX
IOUT = 0
3/17
GS8721/8722/8724
Electrical Characteristics
(At Vs=5V, TA = +25
℃, V
CM =
VS/2, RL = 600
Ω, unless otherwise noted.)
GS8721/2/4
TYP
PARAMETER
MIN/MAX OVER TEMPERATURE
CONDITIONS
℃
+25
℃
+25
℃ to
70℃
0
℃ to
85℃
-40
℃
125℃
-40 to
MIN /
UNITS
MAX
DYNAMIC PERFORMANCE
Gain-Bandwidth Product (GBP)
RL = 10kΩ, CL = 100pF
11
MHz
TYP
Phase Margin (φO)
RL = 10kΩ, CL = 100pF
51
Degrees
TYP
Full Power Bandwidth (BWP)
<1% distortion, R = 600Ω
400
kHz
TYP
Slew Rate (SR)
G = +1, 2V Step, RL = 10kΩ
9
V/µs
TYP
Settling Time to 0.1% (tS)
G = +1, 2V Step, RL = 600Ω
0.3
µs
TYP
Overload Recovery Time
VIN ·Gain = VS, RL = 600Ω
1.5
µs
TYP
f = 1kHz
11.5
nV / Hz
TYP
f = 10kHz
8
nV / Hz
TYP
L
NOISE PERFORMANCE
Voltage Noise Density (en)
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GS8721/8722/8724
Typical Performance characteristics
℃, V
(At Vs=5V, TA = +25
CM =
VS/2, RL = 600Ω, unless otherwise noted.)
Large-Signal Step Response
Voltage (500mV/div)
Large-Signal Step Response
Voltage (1V/div)
Vs=5V
G=+1
CL=100pF
RL=10KΩ
Vs=2.5V
G=+1
CL=100pF
RL=10 KΩ
µ
µ
Small-Signal Step Response
Small-Signal Step Response
Voltage (50mV/div)
Time (1 s/div)
Voltage (50mV/div)
Time (1 s/div)
Vs=5V
G=+1
CL=100pF
RL=10 KΩ
Vs=2.5V
G=+1
CL=100pF
RL=10 KΩ
µ
µ
Time (1 s/div)
Time (1 s/div)
Positive Overload Recovery
Negative Overload Recovery
50mV
VIN
RL= 600Ω
G=-100
±
50mV
VIN
/div
±
Vs= 2.5V
VIN=50mVp-p
Vs= 2.5V
VIN=50mVp-p
/div
RL=600Ω
G=-100
1V
0.5V
/div
VOUT
/div
VOUT
µ
µ
Time (2 s/div)
Time (2 s/div)
5/17
V1
0
GS8721
GS8721/8722/8724
Typical Performance characteristics
CM =
VS/2, RL = 600Ω, unless otherwise noted.)
Vs=5V
℃
135
℃
25
℃
-5
50
Sinking Current
Supply Current (mA)
Sourcing Current
Supply Current vs. Temperature
Vs=2.5
Vs=5
Vs=3
℃
Output Current(mA)
Temperature
emperature ( )
Input Voltage Noise Spectral Density vs. Frequency
Open Loop Gain, Phase Shift vs. Frequency
Vs=5V
Open Loop Gain (dB)
Voltage Noise (nV/√Hz
Output Voltage (V)
Output Voltage Swing vs.Output Current
Vs=5V
CL=100pF
RL=10 KΩ
Frequency (Hz)
Frequency (Hz)
CMRR vs. Frequency
PSRR vs. Frequency
Phase Shift (Degrees)
℃, V
(At Vs=5V, TA = +25
PSRR (dB)
CMRR (dB)
Vs=5V
PSRR+
PSRR-
Frequency (Hz)
V1
Frequency (Hz)
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GS8721/8722/8724
Application Note
Size
GS872X series op amps are unity-gain stable and suitable for a wide range of general-purpose applications. The small
footprints of the GS872X series packages save space on printed circuit boards and enable the design of smaller electronic
products.
Power Supply Bypassing and Board Layout
GS872X series operates from a single 2.1V to 5.5V supply or dual ±1.05V to ±2.75V supplies. For best performance, a 0.1µF
ceramic capacitor should be placed close to the VDD pin in single supply operation. For dual supply operation, both VDD and VSS
supplies should be bypassed to ground with separate 0.1µF ceramic capacitors.
Low Supply Current
The low supply current (typical 1.1mA per channel) of GS872X series will help to maximize battery life. They are ideal for
battery powered systems
Operating Voltage
GS872X series operate under wide input supply voltage (2.1V to 5.5V). In addition, all temperature specifications apply from
o
o
-40 C to +125 C. Most behavior remains unchanged throughout the full operating voltage range. These guarantees ensure
operation throughout the single Li-Ion battery lifetime
Rail-to-Rail Input
The input common-mode range of GS872X series extends 100mV beyond the supply rails (VSS-0.1V to VDD+0.1V). This is
achieved by using complementary input stage. For normal operation, inputs should be limited to this range.
Rail-to-Rail Output
Rail-to-Rail output swing provides maximum possible dynamic range at the output. This is particularly important when
operating in low supply voltages. The output voltage of GS872X series can typically swing to less than 2mV from supply rail in
light resistive loads (>100kΩ), and 15mV of supply rail in moderate resistive loads (10kΩ).
Capacitive Load Tolerance
The GS872X family is optimized for bandwidth and speed, not for driving capacitive loads. Output capacitance will create a
pole in the amplifier’s feedback path, leading to excessive peaking and potential oscillation. If dealing with load capacitance is
a requirement of the application, the two strategies to consider are (1) using a small resistor in series with the amplifier’s output
and the load capacitance and (2) reducing the bandwidth of the amplifier’s feedback loop by increasing the overall noise gain.
Figure 2. shows a unity gain follower using the series resistor strategy. The resistor isolates the output from the capacitance
and, more importantly, creates a zero in the feedback path that compensates for the pole created by the output capacitance.
Figure 2. Indirectly Driving a Capacitive Load Using Isolation Resistor
The bigger the RISO resistor value, the more stable VOUT will be. However, if there is a resistive load RL in parallel with the
capacitive load, a voltage divider (proportional to RISO/RL) is formed, this will result in a gain error.
The circuit in Figure 3 is an improvement to the one in Figure 2. RF provides the DC accuracy by feed-forward the VIN to RL. CF
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GS8721/8722/8724
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 the phase margin in the overall feedback loop. Capacitive drive can be increased
by increasing the value of CF. This in turn will slow down the pulse response.
Figure 3. Indirectly Driving a Capacitive Load with DC Accuracy
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GS8721/8722/8724
Typical Application Circuits
Differential amplifier
The differential amplifier allows the subtraction of two input voltages or cancellation of a signal common the two inputs. It is useful
as a computational amplifier in making a differential to single-end conversion or in rejecting a common mode signal. Figure 4.
shown the differential amplifier using GS872X.
Figure 4. Differential Amplifier
VOUT= ( RR13++RR24 ) RR14 VIN − RR12 VIP +( RR13++RR24 ) RR13 VREF
If the resistor ratios are equal (i.e. R1=R3 and R2=R4), then
VOUT =
R2
R1
(VIP − VIN ) + VREF
Low Pass Active Filter
The low pass active filter is shown in Figure 5. The DC gain is defined by –R2/R1. The filter has a -20dB/decade roll-off after its
corner frequency ƒC=1/(2πR3C1).
Figure 5. Low Pass Active Filter
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GS8721/8722/8724
Instrumentation Amplifier
The triple GS872X can be used to build a three-op-amp instrumentation amplifier as shown in Figure 6. The amplifier in Figure 6
is a high input impedance differential amplifier with gain of R2/R1. The two differential voltage followers assure the high input
impedance of the amplifier.
Figure 6. Instrument Amplifier
.
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GS8721/8722/8724
Package Information
MSOP-8
V1
11/17
GS8721/8722/8724
SOP-8
V1
12/17
GS8721/8722/8724
SOT23-5
V1
13/17
GS8721/8722/8724
SOT23-6
V1
14/17
GS8721/8722/8724
SC70-5
V1
15/17
GS8721/8722/8724
TSSOP-14
V1
16/17
GS8721/8722/8724
SOP-14
V1
17/17