GS8634C
LOW COST 6MHZ CMOS Rail-to-Rail IO Opamps
Features
•
Single-Supply Operation from +2.1V ~ +5.5V
•
Operating Temperature: -40°C ~ +125°C
•
Rail-to-Rail Input / Output
•
Small Package:
•
Gain-Bandwidth Product: 6MHz (Typ.)
GS8634C Available in SOP-14 Package
•
Low Input Bias Current: 1pA (Typ.)
•
Low Offset Voltage: 3.5mV (Max.)
•
Quiescent Current: 470µA per Amplifier (Typ.)
General Description
μ
The GS8634C have a high gain-bandwidth product of 6MHz, a slew rate of 4.2V/ s, and a quiescent current of 470
μA per
amplifier at 5V. The GS8634C is 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 GS8634C. They are specified over the extended industrial temperature range (-40
℃ to +125℃).
The GS8634C Quad is available in Green SOP-14 package.
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
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
V1
+160°C
1/11
GS8634C
Storage Temperature Range
-55°C
Lead Temperature (soldering, 10sec)
Package Thermal Resistance (TA=+25
+150°C
+260°C
℃)
SOP-14, θJA
125°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
CHANNEL
ORDER NUMBER
GS8634C
Quad
GS8634C-SR
V1
PACKAGE
PACKAGE
MARKING
DESCRIPTION
OPTION
INFORMATION
SOP-14
Tape and Reel,2500
GS8634C
2/11
GS8634C
Electrical Characteristics
(At Vs=5V, TA = +25
℃, V
CM
= VS/2, RL = 600
Ω, unless otherwise noted.)
GS8634C
TYP
PARAMETER
MIN/MAX OVER TEMPERATURE
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
90
VS = 5.5V, VCM = -0.1V to 5.6V
83
RL = 600Ω,VO = 0.15V to 4.85V
97
RL = 10kΩ,VO = 0.05V to 4.95V
108
Input Offset Voltage Drift (∆VOS/∆T)
73
90
70
87
70
86
65
79
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
3
Ω
TYP
Turn-On Time
4
µs
TYP
Turn-Off Time
1.2
µs
TYP
OUTPUT CHARACTERISTICS
Output Voltage Swing from Rail
Output Current (IOUT)
Closed-Loop Output Impedance
53
f = 200kHz, G = 1
49
45
40
35
POWER-DOWN DISABLE
POWER SUPPLY
Operating Voltage Range
Power Supply Rejection Ratio (PSRR)
2.1
2.1
2.1
V
MIN
5.5
5.5
5.5
5.5
V
MAX
91
74
72
72
68
dB
MIN
470
650
727
750
815
µA
MAX
VS = +2.5V to +5.5V
VCM = (-VS) + 0.5V
Quiescent Current/Amplifier (IQ)
2.1
IOUT = 0
1
V1
3/11
GS8634C
Electrical Characteristics
(At Vs=5V, TA = +25
℃, V
CM =
VS/2, RL = 600
Ω, unless otherwise noted.)
GS8634C
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
6
MHz
TYP
Phase Margin (φO)
RL = 10kΩ, CL = 100pF
53
Degrees
TYP
Full Power Bandwidth (BWP)
<1% distortion, R = 600Ω
250
kHz
TYP
Slew Rate (SR)
G = +1, 2V Step, RL = 10kΩ
4.2
V/µs
TYP
Settling Time to 0.1% (tS)
G = +1, 2V Step, RL = 600Ω
0.4
µs
TYP
Overload Recovery Time
VIN ·Gain = VS, RL = 600Ω
2.5
µs
TYP
f = 1kHz
13
nV / Hz
TYP
f = 10kHz
9.5
nV / Hz
TYP
L
NOISE PERFORMANCE
Voltage Noise Density (en)
V1
4/11
GS8634C
Typical Performance characteristics
℃, V
(At Vs=5V, TA = +25
CM =
VS/2, RL = 600Ω, unless otherwise noted.)
Large-Signal Step Response
Voltage (500mV/div)
Voltage (1V/div)
Large-Signal Step Response
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
VIN
±
Vs= 2.5V
VIN=-50mVp-p
50mV
/div
50mV
VIN
/div
RL=600Ω
G=-100
RL=600Ω
G=-100
VOUT
±
1V
Vs= 2.5V
VIN=50mVp-p
/div
500mV
/div
VOUT
µ
Time (2 s/div)
V1
µ
Time (2 s/div)
5/11
GS8634C
Typical Performance characteristics
CM =
VS/2, RL = 600Ω, unless otherwise noted.)
Vs=5V
℃
135
℃
℃
-50
25
Sinking Current
Supply Current (µA)
Sourcing Current
Supply Current vs. Temperature
Vs=2.5
Vs=5
Vs=3
℃
Output Current(mA)
Temperature ( )
Input Voltage Noise Spectral Density vs. Frequency
Open Loop Gain, Phase Shift vs. Frequency
Vs=5V
CL=100pF
RL=10KΩ
Open Loop Gain (dB)
Voltage Noise (nV/√Hz)
Output Voltage (V)
Output Voltage Swing vs.Output Current
Vs=5V
CL=100pF
RL=10KΩ
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
Frequency (kHz)
V1
Vs=5V
CL=100pF
RL=10KΩ
Frequency (kHz)
6/11
GS8634C
Application Note
Size
GS8634C opamp is unity-gain stable and suitable for a wide range of general-purpose applications. The small footprints of the
GS8634C package save space on printed circuit boards and enable the design of smaller electronic products.
Power Supply Bypassing and Board Layout
GS8634C operate 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 470uA per channel) of GS8634C will help to maximize battery life. They are ideal for battery
powered systems
Operating Voltage
o
GS8634C operate under wide input supply voltage (2.1V to 5.5V). In addition, all temperature specifications apply from -40 C
o
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 GS8634C 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 GS8634C can typically swing to less than 2mV from supply rail in light
resistive loads (>100kΩ), and 60mV of supply rail in moderate resistive loads (10kΩ).
Capacitive Load Tolerance
The GS8634C 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
and RISO serve to counteract the loss of phase margin by feeding the high frequency component of the output signal back to the
V1
7/11
GS8634C
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.
CF
RF
-
RISO
VOUT
VIN
+
CL
RL
Figure 3. Indirectly Driving a Capacitive Load with DC Accuracy
V1
8/11
GS8634C
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 GS8634C.
Figure 4. Differential Amplifier
VOUT= ( RR13++RR24 ) RR41 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).
C1
R2
R1
VIN
VOUT
+
R3
Figure 5. Low Pass Active Filter
V1
9/11
GS8634C
Instrumentation Amplifier
The triple GS8634C 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
.
V1
10/11
GS8634C
Package Information
SOP-14
V1
11/11