ETC NCS2001/D

NCS2001
Sub-One Volt Rail-to-Rail
Operational Amplifier
The NCS2001 is an industry first sub–one volt operational amplifier
that features a rail–to–rail common mode input voltage range, along
with rail–to–rail output drive capability. This amplifier is guaranteed
to be fully operational down to 0.9 V, providing an ideal solution for
powering applications from a single cell Nickel Cadmium (NiCd) or
Nickel Metal Hydride (NiMH) battery. Additional features include no
output phase reversal with overdriven inputs, trimmed input offset
voltage of 0.5 mV, extremely low input bias current of 40 pA, and a
unity gain bandwidth of 1.4 MHz at 5.0 V. The tiny NCS2001 is the
ideal solution for small portable electronic applications and is
available in the space saving Thin SOT–23–5 and SC70–5 packages
with two industry standard pinouts.
Features
•
•
•
•
•
•
•
•
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LOW VOLTAGE
RAIL–TO–RAIL
OPERATIONAL AMPLIFIER
MARKING
DIAGRAMS
0.9 V Guaranteed Operation
Rail–to–Rail Common Mode Input Voltage Range
Rail–to–Rail Output Drive Capability
No Output Phase Reversal for Over–Driven Input Signals
0.5 mV Trimmed Input Offset
10 pA Input Bias Current
1.4 MHz Unity Gain Bandwidth at 2.5 V, 1.1 MHz at 0.5 V
Tiny SC70–5 and Thin SOT–23–5 Packages
1
4
5
12
3
5
SC70–5
Q SUFFIX
CASE 419A
AAx
1
x = G for SN1
H for SN2
I for SQ1
J for SQ2
Y = Year
W = Work Week
PIN CONNECTIONS
Single Cell NiCd/NiMH Battery Powered Applications
Cellular Telephones
Pagers
Personal Digital Assistants
Electronic Games
Digital Cameras
Camcorders
Hand Held Instruments
Rail to Rail Input
AAxYW
1
Typical Applications
•
•
•
•
•
•
•
•
5
THIN SOT–23–5
N SUFFIX
CASE 483
5
VOUT
1
VCC
Non–Inverting
Input
2
5
VEE
4
Inverting
Input
+ –
3
Style 1 Pinout (SN1T1, SQ1T1)
Rail to Rail Output
VOUT
1
VEE
Non–Inverting
Input
2
5
VCC
4
Inverting
Input
+ –
3
Style 2 Pinout (SN2T2, SQ2T2)
0.8 V
to
7.0 V
+
-
ORDERING INFORMATION
Device
This device contains 63 active transistors.
June, 2001 – Rev. 4
1
Shipping
NCS2001SN1T1
Thin
SOT–23–5
3000 Tape & Reel
NCS2001SN2T1
Thin
SOT–23–5
3000 Tape & Reel
NCS2001SQ1T1
SC70–5
3000 Tape & Reel
NCS2001SQ2T1
SC70–5
3000 Tape & Reel
Figure 1. Typical Application
 Semiconductor Components Industries, LLC, 2001
Package
Publication Order Number:
NCS2001/D
NCS2001
MAXIMUM RATINGS
Rating
Symbol
Value
Unit
VS
7.0
V
Input Differential Voltage Range (Note 1)
VIDR
VEE –300 mV to
7.0 V
V
Input Common Mode Voltage Range (Note 1)
VICR
VEE –300 mV to
7.0 V
V
Output Short Circuit Duration (Note 2)
tSc
Indefinite
sec
Junction Temperature
TJ
150
°C
RJA
PD
235
340
°C/W
mW
RJA
PD
280
286
°C/W
mW
Tstg
–65 to 150
°C
VESD
2000
V
Supply Voltage (VCC to VEE)
Power Dissipation and Thermal Characteristics
Thin SOT–23–5 Package
Thermal Resistance, Junction to Air
Power Dissipation @ TA = 70°C
SC70–5 Package
Thermal Resistance, Junction to Air
Power Dissipation @ TA = 70°C
Storage Temperature Range
ESD Protection at any Pin Human Body Model (Note 3)
1. Either or both inputs should not exceed the range of VEE –300 mV to VEE +7.0 V.
2. Maximum package power dissipation limits must be observed to ensure that the maximum junction temperature is not exceeded.
TJ = TA + (PD RJA)
3. ESD data available upon request.
DC ELECTRICAL CHARACTERISTICS
(VCC = 2.5 V, VEE = –2.5 V, VCM = VO = 0 V, RL to Gnd, TA = 25°C unless otherwise noted.)
Characteristics
Symbol
Input Offset Voltage
VCC = 0.45 V, VEE = –0.45 V
TA = 25°C
TA = 0°C to 70°C
TA = –40°C to 105°C
VCC = 1.5 V, VEE = –1.5 V
TA = 25°C
TA = 0°C to 70°C
TA = –40°C to 105°C
VCC = 2.5 V, VEE = –2.5 V
TA = 25°C
TA = 0°C to 70°C
TA = –40°C to 105°C
Min
Typ
Max
VIO
Unit
mV
–6.0
–8.5
–9.5
0.5
–
–
6.0
8.5
9.5
–6.0
–7.0
–7.5
0.5
–
–
6.0
7.0
7.5
–6.0
–7.5
–7.5
0.5
–
–
6.0
7.5
7.5
∆VIO/∆T
–
8.0
–
µV/°C
IIB
–
10
–
pA
Input Common Mode Voltage Range
VICR
–
VEE to VCC
–
V
Large Signal Voltage Gain
VCC = 0.45 V, VEE = –0.45 V
RL = 10 k
RL = 2.0 k
VCC = 1.5 V, VEE = –1.5 V
RL = 10 k
RL = 2.0 k
VCC = 2.5 V, VEE = –2.5 V
RL = 10 k
RL = 2.0 k
AVOL
Input Offset Voltage Temperature Coefficient (RS = 50)
TA = –40°C to 105°C
Input Bias Current (VCC = 1.0 V to 5.0 V)
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2
kV/V
–
–
40
20
–
–
–
–
40
40
–
–
20
15
40
40
–
–
NCS2001
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 2.5 V, VEE = –2.5 V, VCM = VO = 0 V, RL to Gnd, TA = 25°C unless otherwise noted.)
Characteristics
Symbol
Output Voltage Swing, High State Output (VID = +0.5 V)
VCC = 0.45 V, VEE = –0.45 V
TA = 25°C
RL = 10 k
RL = 2.0 k
TA = 0°C to 70°C
RL = 10 k
RL = 2.0 k
TA = –40°C to 105°C
RL = 10 k
RL = 2.0 k
VCC = 1.5 V, VEE = –1.5 V
TA = 25°C
RL = 10 k
RL = 2.0 k
TA = 0°C to 70°C
RL = 10 k
RL = 2.0 k
TA = –40°C to 105°C
RL = 10 k
RL = 2.0 k
VCC = 2.5 V, VEE = –2.5 V
TA = 25°C
RL = 10 k
RL = 2.0 k
TA = 0°C to 70°C
RL = 10 k
RL = 2.0 k
TA = –40°C to 105°C
RL = 10 k
RL = 2.0 k
VOH
Output Voltage Swing, Low State Output (VID = –0.5 V)
VCC = 0.45 V, VEE = –0.45 V
TA = 25°C
RL = 10 k
RL = 2.0 k
TA = 0°C to 70°C
RL = 10 k
RL = 2.0 k
TA = –40°C to 105°C
RL = 10 k
RL = 2.0 k
VCC = 1.5 V, VEE = –1.5 V
TA = 25°C
RL = 10 k
RL = 2.0 k
TA = 0°C to 70°C
RL = 10 k
RL = 2.0 k
TA = –40°C to 105°C
RL = 10 k
RL = 2.0 k
VCC = 2.5 V, VEE = –2.5 V
TA = 25°C
RL = 10 k
RL = 2.0 k
TA = 0°C to 70°C
RL = 10 k
RL = 2.0 k
TA = –40°C to 105°C
RL = 10 k
RL = 2.0 k
VOL
Min
3
Max
Unit
V
0.40
0.35
0.494
0.466
–
–
0.40
0.35
–
–
–
–
0.40
0.35
–
–
–
–
1.45
1.40
1.498
1.480
–
–
1.45
1.40
–
–
–
–
1.45
1.40
–
–
–
–
2.45
2.40
2.498
2.475
–
–
2.45
2.40
–
–
–
–
2.45
2.40
–
–
–
–
V
–
–
–0.494
–0.480
–0.40
–0.35
–
–
–
–
–0.40
–0.35
–
–
–
–
–0.40
–0.35
–
–
–1.493
–1.480
–1.45
–1.40
–
–
–
–
–1.45
–1.40
–
–
–
–
–1.45
–1.40
–2.492
–2.479
–2.45
–2.40
–
–
–
–
–2.45
–2.40
–
–
–
–
–2.45
–2.40
–
–
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Typ
NCS2001
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 2.5 V, VEE = –2.5 V, VCM = VO = 0 V, RL to Gnd, TA = 25°C unless otherwise noted.)
Characteristics
Symbol
Min
Typ
Max
Unit
Common Mode Rejection Ratio (Vin = 0 to 5.0 V)
CMRR
60
70
–
dB
Power Supply Rejection Ratio (VCC = 0.5 V to 2.5 V, VEE = –2.5 V)
PSRR
55
65
–
dB
Output Short Circuit Current
VCC = 0.45 V, VEE = –0.45 V, VID = 0.4 V
Source Current High Output State
Sink Current Low Output State
VCC = 1.5 V, VEE = –1.5 V, VID = 0.5 V
Source Current High Output State
Sink Current Low Output State
VCC = 2.5 V, VEE = –2.5 V, VID = 0.5 V
Source Current High Output State
Sink Current Low Output State
ISC
Power Supply Current (Per Amplifier, VO = 0 V)
VCC = 0.45 V, VEE = –0.45 V
TA = 25°C
TA = 0°C to 70°C
TA = –40°C to 105°C
VCC = 1.5 V, VEE = –1.5 V
TA = 25°C
TA = 0°C to 70°C
TA = –40°C to 105°C
VCC = 2.5 V, VEE = –2.5 V
TA = 25°C
TA = 0°C to 70°C
TA = –40°C to 105°C
ID
mA
0.5
–
1.2
–3.0
–
–1.5
15
–
29
–40
–
–20
40
–
76
–96
–
–50
mA
–
–
–
0.51
–
–
1.10
1.10
1.10
–
–
–
0.72
–
–
1.40
1.40
1.40
–
–
–
0.82
–
–
1.50
1.50
1.50
AC ELECTRICAL CHARACTERISTICS
(VCC = 2.5 V, VEE = –2.5 V, VCM = VO = 0 V, RL to Gnd, TA = 25°C unless otherwise noted.)
Characteristics
Symbol
Min
Typ
Max
Unit
Differential Input Resistance (VCM = 0 V)
Rin
–
1.0
–
tera Ω
Differential Input Capacitance (VCM = 0 V)
Cin
–
3.0
–
pF
en
–
100
–
nV/√Hz
–
–
0.5
1.1
1.3
1.4
–
–
–
Am
–
6.5
–
dB
Equivalent Input Noise Voltage (f = 1.0 kHz)
Gain Bandwidth Product (f = 100 kHz)
VCC = 0.45 V, VEE = –0.45 V
VCC = 1.5 V, VEE = –1.5 V
VCC = 2.5 V, VEE = –2.5 V
GBW
Gain Margin (RL = 10 k, CL = 5.0 pf)
MHz
φm
–
60
–
Deg
Power Bandwidth (VO = 4.0 Vpp, RL = 2.0 k, THD = 1.0%, AV = 1.0)
BWP
–
80
–
kHz
Total Harmonic Distortion (VO = 4.0 Vpp, RL = 2.0 k, AV = 1.0)
f = 1.0 kHz
f = 10 kHz
THD
–
–
0.008
0.08
–
–
1.0
1.0
1.6
1.6
6.0
6.0
Phase Margin (RL = 10 k, CL = 5.0 pf)
Slew Rate (VS = 2.5 V, VO = –2.0 V to 2.0 V, RL = 2.0 k, AV = 1.0)
Positive Slope
Negative Slope
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4
%
SR
V/µs
NCS2001
0
VCC
–0.2
VCC = 2.5 V
VEE = –2.5 V
RL to Gnd
TA = 25°C
High State Output
Sourcing Current
–0.4
Vsat, Output Saturation Voltage (V)
–0.6
0.6
0.4
Low State Output
Sinking Current
0.2
VEE
0
100
1.0 k
10 k
100 k
VCC
–0.1
VCC = 2.5 V
VEE = –2.5 V
IL to Gnd
TA = 25°C
–0.2
–0.3
High State Output
Sourcing Current
Low State Output
Sinking Current
0.3
0.2
0.1
VEE
0
0
1.0 M
2.0
4.0
10
12
IL, Load Current (mA)
Figure 2. Split Supply Output Saturation vs.
Load Resistance
Figure 3. Split Supply Output Saturation vs.
Load Current
1000
100
VCC = 2.5 V
VEE = –2.5 V
RL = 10 k to Gnd
TA = 25°C
Gain
80
10
VCC = 2.5 V
VEE = –2.5 V
1.0
AVOL, Gain (dB)
100
IIB, Input Current (pA)
8.0
6.0
RL, Load Resistance ()
Phase
0
45
60
90
Phase
Margin = 60°
40
135
20
180
0
0
25
50
75
100
0
1.0
125
10
100
1.0 k
10 k
100 k
1.0 M
TA, Ambient Temperature (°C)
f, Frequency (Hz)
Figure 4. Input Bias Current vs. Temperature
Figure 5. Gain and Phase vs. Frequency
VS = ±2.5 V
AV = 1.0
RL = 10 k
CL = 10 pF
TA = 25°C
50 mV/div
500 mV/div
VS = ±2.5 V
RL = 10 k
CL = 10 pf
AV = 1.0
TA = 25°C
t, time (500 ns/Div)
t, time (1.0 µs/Div)
Figure 6. Transient Response
Figure 7. Slew Rate
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5
10 M
Φm, Excess Phase (°)
Vsat, Output Saturation Voltage (V)
0
NCS2001
80
6
CMR, Common Mode Rejection (dB)
VO, Output Voltage (Vpp)
VS = ±2.5 V
5
AV = 1.0
RL = 10 k
TA = 25°C
4
VS = ±1.5 V
3
2
VS = ±0.5 V
1
0
70
VCC = 2.5 V
VEE = –2.5 V
TA = 25°C
60
50
40
30
20
10
0
1.0 k
10 k
100 k
f, Frequency (Hz)
1.0 M
10
100
Figure 8. Output Voltage vs. Frequency
60
PSR –
IISCI, Output Short Circuit Current (mA)
PSR, Power Supply Rejection (dB)
PSR +
VCC = 2.5 V
VEE = –2.5 V
TA = 25°C
40
20
0
10
100
1.0 k
10 k
100 k
1.0 M
Output Pulsed Test
at 3% Duty Cycle
–40°C
160
25°C
120
85°C
80
40
0
10 M
±0.5
0
f, Frequency (Hz)
±1.0
±1.5
±2.0
±2.5
±3.0
±3.5
VS, Supply Voltage (V)
Figure 11. Output Short Circuit Sinking
Current vs. Supply Voltage
1.2
200
Output Pulsed Test
at 3% Duty Cycle
TA = 125°C
–40°C
1.0
160
ID, Supply Current (mA)
IISCI, Output Short Circuit Current (mA)
10 M
200
Figure 10. Power Supply Rejection
vs. Frequency
25°C
120
85°C
80
40
0
1.0 M
Figure 9. Common Mode Rejection
vs. Frequency
100
80
1.0 k
10 k
100 k
f, Frequency (Hz)
TA = 25°C
TA = –55°C
0.8
0.6
0.4
0.2
0
±0.5
±1.0
±1.5
±2.0
±2.5
±3.0
0
±3.5
±0.5
0
±1.0
±1.5
±2.0
±2.5
VS, Supply Voltage (V)
VS, Supply Voltage (V)
Figure 12. Output Short Circuit Sourcing
Current vs. Supply Voltage
Figure 13. Supply Current vs. Supply Voltage
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6
NCS2001
10
THD, Total Harmonic Distortion (%)
THD, Total Harmonic Distortion (%)
10
AV = 1000
1.0
0.1
AV = 100
AV = 10
AV = 1.0
VS = ±0.5 V
Vout = 0.4 Vpp
0.01
10
100
1.0 k
RL = 2.0 k
TA = 25°C
10 k
VS = ±0.5 V
Vout = 0.4 Vpp
100
RL = 10 k
TA = 25°C
Figure 15. Total Harmonic Distortion vs.
Frequency with 1.0 V Supply
10 k
100 k
10
THD, Total Harmonic Distortion (%)
THD, Total Harmonic Distortion (%)
AV = 1.0
Figure 14. Total Harmonic Distortion vs.
Frequency with 1.0 V Supply
AV = 100
0.1
AV = 10
VS = ±2.5 V
Vout = 4.0 Vpp
RL = 2.0 k
TA = 25°C
0.01
AV = 1.0
0.001
10
100
1.0 k
10 k
1.0
AV = 1000
0.1
AV = 100
AV = 10
0.01
VS = ±2.5 V
Vout = 4.0 Vpp
RL = 10 k
TA = 25°C
AV = 1.0
0.001
10
100 k
100
1.0 k
10 k
100 k
f, Frequency (Hz)
f, Frequency (Hz)
Figure 16. Total Harmonic Distortion vs.
Frequency with 5.0 V Supply
Figure 17. Total Harmonic Distortion vs.
Frequency with 5.0 V Supply
GBW, Gain Bandwidth Product (MHz)
2.0
+Slew Rate, VS = ±2.5 V
SR, Slew Rate (V/µs)
AV = 10
1.0 k
f, Frequency (Hz)
1.0
1.5
–Slew Rate, VS = ±2.5 V
–Slew Rate, VS = ±0.45 V
0
–50
0.1
AV = 100
f, Frequency (Hz)
AV = 1000
0.5
1.0
0.01
10
100 k
10
1.0
AV = 1000
+Slew Rate, VS = ±0.45 V
–25
0
25
RL = 10 k
CL = 10 pF
TA = 25°C
50
75
100
125
2.0
1.5
1.0
VCC = 2.5 V
VEE = –2.5 V
RL = 10 k
CL = 10 pF
0.5
0
–50
–25
0
25
50
75
100
TA, Ambient Temperature (°C)
TA, Ambient Temperature (°C)
Figure 18. Slew Rate vs. Temperature
Figure 19. Gain Bandwidth Product vs.
Temperature
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7
125
NCS2001
180
VS = ±2.5 V
220
RL = 10 k
TA = 25°C
–40
10 k
100 k
1.0 M
20
20
Gain Margin
–25
0
25
50
75
100
Figure 20. Voltage Gain and Phase vs.
Frequency
Figure 21. Gain and Phase Margin vs.
Temperature
80
70
Phase Margin
Phase Margin
Am, Gain Margin (dB)
50
50
VCC = 2.5 V
VEE = –2.5 V
RL = 10 k
CL = 10 pF
TA = 25°C
40
30
20
Gain Margin
0
125
80
60
10
20
60
60
AV = 100
VCC = 2.5 V
VEE = –2.5 V
RL = 10 k to Gnd
TA = 25°C
40
40
Gain Margin
20
20
10
0
10
100
1.0 k
0
100 k
10 k
0
1.0
0
1000
Rt, Differential Source Resistance (Ω)
10
100
CL, Output Load Capacitance (pF)
Figure 22. Gain and Phase Margin vs.
Differential Source Resistance
Figure 23. Gain and Phase Margin vs.
Output Load Capacitance
80
8.0
80
6.0
4.0
RL = 10 k
TA = 25°C
Split Supplies
2.0
0
0
±0.5
±1.0
±1.5
±2.0
±2.5
±3.0
60
60
RL = 10 k
CL = 10 pF
TA = 25°C
40
Gain Margin
20
0
±3.5
40
0
±0.5
±1.0
±1.5
±2.0
20
±2.5
±3.0
VS, Supply Voltage (V)
VS, Supply Voltage (V)
Figure 24. Output Voltage Swing vs.
Supply Voltage
Figure 25. Gain and Phase Margin vs.
Supply Voltage
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8
0
±3.5
Φm, Phase Margin (°)
Phase Margin
Am, Gain Margin (dB)
VOUT, Output Volltage (Vpp)
40
TA, Ambient Temperature (°C)
60
30
VCC = 2.5 V
VEE = –2.5 V
40
RL = 10 k
CL = 10 pF
f, Frequency (Hz)
70
40
60
Phase Margin
0
–50
260
100 M
10 M
60
Φm, Phase Margin (°)
VS = ±0.5 V
0
80
Φm, Phase Margin (°)
140
20
–20
AV, Gain Margin (dB)
100
Am, Gain Margin (dB)
VS = ±0.5 V
Φm, Phase Margin (°)
AVOL, Gain (dB)
40
80
60
VS = ±2.5 V
Φm, Excess Phase (°)
60
NCS2001
80
VIO, Input Offset Voltage (mV)
20
RL = 2.0 k
RL = 10 k
60
40
20
TA = 25°C
0
0
±0.5
±1.0
±1.5
±2.0
VIO, Input Offset Voltage (mV)
10
5
10
5
0
–5
–10
–15
–2.0
–1.0
0
1.0
2.0
3.0
VS, Supply Voltage (V)
VCM, Common Mode Input Voltage Range (V)
Figure 26. Open Loop Voltage Gain vs.
Supply Voltage
Figure 27. Input Offset Voltage vs. Common
Mode Input Voltage Range VS = 2.5 V
20
15
VS = ±2.5 V
RL = ∞
CL = 0
AV = 1.0
TA = 25°C
15
–20
–3.0
±2.5
VS = ±0.45 V
RL = ∞
CL = 0
AV = 1.0
TA = 25°C
0
–5
–10
–15
–20
–0.5 –0.4 –0.3 –0.2 –0.1
0
0.1
0.2
0.3
0.4
0.5
VCM, Common Mode Input Voltage Range (V)
AVOL, Open Loop Gain (dB)
100
3.0
2.0
1.0
Vio = 5.0 mV
RL = ∞
CL = 0
AV = 1.0
TA = 25°C
0
–1.0
–2.0
–3.0
±0.35 ±0.5
VCM, Common Mode Input Voltage Range (V)
±1.0
±1.5
±2.0
±2.5
±3.0
VS, Supply Voltage (V)
Figure 29. Common–Mode Input Voltage Range
vs. Power Supply Voltage
Figure 28. Input Offset Voltage vs. Common
Mode Input Voltage Range, VS = 0.45 V
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NCS2001
APPLICATION INFORMATION AND OPERATING DESCRIPTION
Cfb
GENERAL INFORMATION
The NCS2001 is an industry first rail–to–rail input,
rail–to–rail output amplifier that features guaranteed sub
one volt operation. This unique feature set is achieved with
the use of a modified analog CMOS process that allows the
implementation of depletion MOSFET devices. The
amplifier has a 1.0 MHz gain bandwidth product, 2.2 V/µs
slew rate and is operational over a power supply range less
than 0.9 V to as high as 7.0 V.
Rfb
Rin
Input
Cin
Output
Cin = Input and printed circuit board capacitance
Figure 30. Input Capacitance Pole Cancellation
Inputs
The input topology chosen for this device series is
unconventional when compared to most low voltage
operational amplifiers. It consists of an N–channel depletion
mode differential transistor pair that drives a folded cascode
stage and current mirror. This configuration extends the
input common mode voltage range to encompass the VEE
and VCC power supply rails, even when powered from a
combined total of less than 0.9 volts. Figure 27 and 28 show
the input common mode voltage range versus power supply
voltage.
The differential input stage is laser trimmed in order to
minimize offset voltage. The N–channel depletion mode
MOSFET input stage exhibits an extremely low input bias
current of less than 10 pA. The input bias current versus
temperature is shown in Figure 4. Either one or both inputs
can be biased as low as VEE minus 300 mV to as high as
7.0 V without causing damage to the device. If the input
common mode voltage range is exceeded, the output will not
display a phase reversal. If the maximum input positive or
negative voltage ratings are to be exceeded, a series resistor
must be used to limit the input current to less than 2.0 mA.
The ultra low input bias current of the NCS2001 allows
the use of extremely high value source and feedback resistor
without reducing the amplifier’s gain accuracy. These high
value resistors, in conjunction with the device input and
printed circuit board parasitic capacitances C in, will add an
additional pole to the single pole amplifier shown in
Figure 29. If low enough in frequency, this additional pole
can reduce the phase margin and significantly increase the
output settling time. The effects of Cin, can be canceled by
placing a zero into the feedback loop. This is accomplished
with the addition of capacitor Cfb. An approximate value for
Cfb can be calculated by:
Cfb +
Output
The output stage consists of complimentary P and N
channel devices connected to provide rail–to–rail output
drive. With a 2.0 k load, the output can swing within 50 mV
of either rail. It is also capable of supplying over 75 mA
when powered from 5.0 V and 1.0 mA when powered from
0.9 V.
When connected as a unity gain follower, the NCS2001
can directly drive capacitive loads in excess of 820 pF at
room temperature without oscillating but with significantly
reduced phase margin. The unity gain follower
configuration exhibits the highest bandwidth and is most
prone to oscillations when driving a high value capacitive
load. The capacitive load in combination with the
amplifier’s output impedance, creates a phase lag that can
result in an under–damped pulse response or a continuous
oscillation. Figure 32 shows the effect of driving a large
capacitive load in a voltage follower type of setup. When
driving capacitive loads exceeding 820 pF, it is
recommended to place a low value isolation resistor
between the output of the op amp and the load, as shown in
figure 31. The series resistor isolates the capacitive load
from the output and enhances the phase margin. Refer to
figure 33. Larger values of R will result in a cleaner output
waveform but excessively large values will degrade the
large signal rise and fall time and reduce the output
amplitude. Depending upon the capacitor characteristics,
the isolation resistor value will typically be between 50 to
500 ohms. The output drive capability for resistive and
capacitive loads are shown in Figures 2, 3, and 23.
Input
Rin Cin
Rfb
+
-
R
Output
CL
Isolation resistor R = 50 to 500
Figure 31. Capacitance Load Isolation
Note that the lowest phase margin is observed at cold
temperature and low supply voltage.
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NCS2001
Vin
VS = ±0.45 V
Vin = 0.8 Vpp
R=0
CL = 820 pF
AV = 1.0
TA = 25°C
Vout
Figure 32. Small Signal Transient Response with Large Capacitive Load
Vin
VS = ±0.45 V
Vin = 0.8 Vpp
R = 51
CL = 820 pF
AV = 1.0
TA = 25°C
Vout
Figure 33. Small Signal Transient Response with Large
Capacitive Load and Isolation Resistor.
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11
NCS2001
RT
470 k
VCC
Output Voltage
0
0.9 V
CT
1.0 nF
Timing Capacitor
Voltage
-
0.33 VCC
fO = 1.5 kHz
+
The non–inverting input threshold levels are set so that
the capacitor voltage oscillates between 1/3 and 2/3 of
VCC. This requires the resistors R1a, R1b and R2 to be of
equal value. The following formula can be used to
approximate the output frequency.
R1a
470 k
0.9 V
R2
470 k
R1b
470 k
0.67 VCC
1
f O 1.39 R TC T
Figure 34. 0.9 V Square Wave Oscillator
cww
D1
1N4148
10 k
VCC
Output Voltage
0
1.0 M
D2
1N4148
10 k
Timing Capacitor
Voltage
0.67 VCC
0.33 VCC
cw
Clock–wise, Low Duty Cycle
VCC
CT
1.0 nF
VCC
Output Voltage
-
0
fO
+
Timing Capacitor
Voltage
R1a
470 k
0.67 VCC
0.33 VCC
Counter–Clock–wise, High Duty Cycle
VCC
R1b
470 k
R2
470 k
The timing capacitor CT will charge through diode D2 and discharge
through diode D1, allowing a variable duty cycle. The pulse width of the
signal can be programmed by adjusting the value of the trimpot. The capacitor voltage will oscillate between 1/3 and 2/3 of VCC, since all the
resistors at the non–inverting input are of equal value.
Figure 35. Variable Duty Cycle Pulse Generator
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NCS2001
R1
1.0 M
2.5 V
R3
1.0 k
+
-
Cin
10 F
≈
10,000 µF
–2.5 V
Ceff. R2
1.0 M
R1
C
R3 in
Figure 36. Positive Capacitance Multiplier
Af
Cf
400 pF
Rf
100 k
fL
R2
10 k
0.5 V
1
f 200 Hz
L 2R C
1 1
+
-
Vin
C1
80 nF
fH
VO
R1
10 k –0.5 V
1
f 4.0 kHz
H 2RC
f f
R
A 1 f 11
f
R2
Figure 37. 1.0 V Voiceband Filter
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NCS2001
Vsupply
VCC
Vin
+
I
-
V
in
sink R sense
Rsense
Figure 38. High Compliance Current Sink
Is
VL
1.0 V
Rsense
RL
R3
1.0 k
R1
1.0 k
R4
+
-
1.0 k
R5
VO
2.4 k
75
Is
VO
435 mA
34.7 mV
212 mA
36.9 mV
R6
For best performance, use low
tolerance resistors.
R2
3.3 k
Figure 39. High Side Current Sense
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NCS2001
PACKAGE DIMENSIONS
THIN SOT–23–5
N SUFFIX
PLASTIC PACKAGE
CASE 483–01
ISSUE A
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. MAXIMUM LEAD THICKNESS INCLUDES LEAD
FINISH THICKNESS. MINIMUM LEAD THICKNESS
IS THE MINIMUM THICKNESS OF BASE
MATERIAL.
D
5
S
4
1
2
B
3
L
DIM
A
B
C
D
G
H
J
K
L
M
S
G
A
J
C
0.05 (0.002)
H
M
K
MILLIMETERS
MIN
MAX
2.90
3.10
1.30
1.70
0.90
1.10
0.25
0.50
0.85
1.00
0.013
0.100
0.10
0.26
0.20
0.60
1.25
1.55
0
10 2.50
3.00
INCHES
MIN
MAX
0.1142 0.1220
0.0512 0.0669
0.0354 0.0433
0.0098 0.0197
0.0335 0.0413
0.0005 0.0040
0.0040 0.0102
0.0079 0.0236
0.0493 0.0610
0
10 0.0985 0.1181
SC70–5
Q SUFFIX
CASE 419A–01
ISSUE E
A
G
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
V
5
DIM
A
B
C
D
G
H
J
K
N
S
V
4
–B–
S
1
2
3
D 5 PL
0.2 (0.008)
M
B
M
N
J
C
H
K
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INCHES
MIN
MAX
0.071
0.087
0.045
0.053
0.031
0.043
0.004
0.012
0.026 BSC
--0.004
0.004
0.010
0.004
0.012
0.008 REF
0.079
0.087
0.012
0.016
MILLIMETERS
MIN
MAX
1.80
2.20
1.15
1.35
0.80
1.10
0.10
0.30
0.65 BSC
--0.10
0.10
0.25
0.10
0.30
0.20 REF
2.00
2.20
0.30
0.40
NCS2001
ON Semiconductor and
are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes
without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular
purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability,
including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or
specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be
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NCS2001/D