NSC LMH6640

LMH6640
TFT-LCD Single, 16V Rail-to-Rail High Output
Operational Amplifier
General Description
Features
The LMH™6640 is a voltage feedback operational amplifier
(VS = 16V, RL= 2 kΩ to V+/2, 25˚C, Typical Values Unless
Specified)
n Supply current (no load)
4 mA
n Output resistance (closed loop 1 MHz)
0.35Ω
n −3 dB BW (AV = 1)
190 MHz
n Settling time ( ± 0.1%, 2 VPP)
35 ns
n Input common mode voltage
−0.3V to 15.1V
n Output voltage swing
100 mV from rails
± 100 mA
n Linear output current
n Total harmonic distortion (2 VPP, 5 MHz)
−64 dBc
n Fully characterized for:
5V & 16V
n No output phase reversal with CMVR exceeded
n Differential gain (RL = 150Ω)
0.12%
n Differential phase (RL = 150Ω)
0.12˚
with a rail-to-rail output drive capability of 100 mA. Employing National’s patented VIP10 process, the LMH6640 delivers a bandwidth of 190 MHz at a current consumption of only
4mA. An input common mode voltage range extending to
0.3V below the V− and to within 0.9V of V+, makes the
LMH6640 a true single supply op-amp. The output voltage
range extends to within 100 mV of either supply rail providing
the user with a dynamic range that is especially desirable in
low voltage applications.
The LMH6640 offers a slew rate of 170 V/µs resulting in a full
power bandwidth of approximately 28 MHz with 5V single
supply (2 VPP, −1 dB). Careful attention has been paid to
ensure device stability under all operating voltages and
modes. The result is a very well behaved frequency response characteristic for any gain setting including +1, and
excellent specifications for driving video cables including
total harmonic distortion of −64 dBc @ 5 MHz, differential
gain of 0.12% and differential phase of 0.12˚.
Applications
n
n
n
n
n
n
TFT panel VCOM buffer amplifier
Active filters
CD/DVD ROM
ADC buffer amplifier
Portable video
Current sense buffer
Typical Application
20086234
Typical Application as a TFT Panel VCOM Driver
LMH™ is a trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation
DS200862
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LMH6640 TFT-LCD Single, 16V Rail-to-Rail High Output Operational Amplifier
November 2004
LMH6640
Absolute Maximum Ratings (Note 1)
Junction Temperature (Note 4)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Soldering Information
+150˚C
Infrared or Convection (20 sec.)
235˚C
Wave Soldering (10 sec.)
260˚C
ESD Tolerance (Note 2)
Human Body Model
2 KV
Machine Model
200V
Operating Ratings (Note 3)
Supply Voltage (V+ – V−)
± 2.5V
VIN Differential
± 10 mA
Input Current
Supply Voltages (V+ – V−)
18V
+
V +0.8V, V −0.8V
Storage Temperature Range
−65˚C to +150˚C
−40˚C to +85˚C
Package Thermal Resistance (Note 4)
−
Voltage at Input/Output Pins
4.5V to 16V
Operating Temperature Range
(Note 4)
5-Pin SOT23
265˚C/W
5V Electrical Characteristics
Unless otherwise specified, All limits guaranteed for TJ = 25˚C, V+ = 5V, V− = 0V, VO = VCM = V+/2 and RL = 2 kΩ to V+/2.
Boldface limits apply at temperature extremes. (Note 9)
Symbol
BW
BW0.1 dB
Parameter
Conditions
Min
(Note 6)
Typ
(Note 5)
AV = +1 (RL = 100Ω)
150
AV = −1 (RL = 100Ω)
58
0.1 dB Gain Flatness
AV = −3
18
−3 dB Bandwidth
Max
(Note 6)
Units
MHz
MHz
FPBW
Full Power Bandwidth
AV = +1, VOUT = 2 VPP, −1 dB
28
MHz
LSBW
-3 dB Bandwidth
AV = +1, VO = 2 VPP (RL = 100Ω)
32
MHz
GBW
Gain Bandwidth Product
AV = +1, (RL = 100Ω)
59
MHz
SR
Slew Rate (Note 8)
AV = −1
en
Input Referred Voltage Noise
in
Input Referred Current Noise
170
V/µs
f = 10 kHz
23
nV/
f = 1 MHz
15
f = 10 kHz
1.1
f = 1 MHz
0.7
THD
Total Harmonic Distortion
f = 5 MHz, VO = 2 VPP, AV = +2
RL = 1 kΩ to V+/2
–65
ts
Settling Time
VO = 2 VPP, ± 0.1%, AV = −1
35
VOS
Input Offset Voltage
IB
Input Bias Current (Note 7)
IOS
Input Offset Current
CMVR
Common Mode Input Voltage
Range
CMRR ≥ 50 dB
4.0
3.6
mV
−1.2
−2.6
−3.25
µA
34
800
1400
nA
–0.3
–0.2
–0.1
4.1
V− ≤ VCM ≤ V+ −1.5V
72
90
AVOL
Large Signal Voltage Gain
VO = 4 VPP, RL = 2 kΩ to V+/2
86
82
95
VO = 3.75 VPP, RL = 150Ω to V+/2
74
70
78
RL = 2 kΩ to V+/2
4.90
4.94
RL = 150Ω to V+/2
4.75
4.80
Output Swing Low
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+
ns
5
7
Common Mode Rejection Ratio
Output Swing High
dBc
1
CMRR
VO
pA/
dB
dB
RL = 2 kΩ to V /2
0.06
0.10
RL = 150Ω to V+/2
0.20
0.25
2
V
V
LMH6640
5V Electrical Characteristics
(Continued)
Unless otherwise specified, All limits guaranteed for TJ = 25˚C, V+ = 5V, V− = 0V, VO = VCM = V+/2 and RL = 2 kΩ to V+/2.
Boldface limits apply at temperature extremes. (Note 9)
Symbol
ISC
IOUT
Parameter
Output Short Circuit Current
(Note 3)
Conditions
Min
(Note 6)
Typ
(Note 5)
Sourcing to V+/2
100
75
130
Sinking from V+/2
100
70
130
Output Current
VO = 0.5V from either Supply
Max
(Note 6)
mA
+75/−90
PSRR
Power Supply Rejection Ratio
4V ≤ V ≤ 6V
IS
Supply Current
No Load
3.7
RIN
Common Mode Input
Resistance
AV = +1, f = 1 kHz, RS = 1 MΩ
15
CIN
Common Mode Input
Capacitance
AV = +1, RS = 100 kΩ
1.7
ROUT
Output Resistance Closed Loop RF = 10 kΩ, f = 1 kHz, AV = −1
+
72
Units
mA
80
dB
5.5
8.0
mA
MΩ
pF
0.1
RF = 10 kΩ, f = 1 MHz, AV = −1
0.4
DG
Differential Gain
NTSC, AV = +2
RL = 150Ω to V+/2
0.13
DP
Differential Phase
NTSC, AV = +2
RL = 150Ω to V+/2
0.10
Ω
%
deg
16V Electrical Characteristics
Unless otherwise specified, All limits guaranteed for TJ = 25˚C, V+ = 16V, V− = 0V, VO = VCM = V+/2 and RL = 2 kΩ to V+/2.
Boldface limits apply at temperature extremes. (Note 9)
Symbol
BW
Parameter
−3 dB Bandwidth
BW0.1 dB
0.1 dB Gain Flatness
Conditions
Min
(Note 6)
Typ
(Note 5)
Max
(Note 6)
Units
AV = +1 (RL = 100Ω)
190
AV = −1 (RL = 100Ω)
60
AV = −2.7
20
MHz
MHz
LSBW
-3 dB Bandwidth
AV = +1, VO = 2 VPP (RL = 100Ω)
35
MHz
GBW
Gain Bandwidth Product
AV = +1, (RL = 100Ω)
62
MHz
SR
Slew Rate (Note 8)
AV = −1
170
V/µs
en
Input Referred Voltage Noise
in
Input Referred Current Noise
f = 10 kHz
23
f = 1 MHz
15
f = 10 kHz
1.1
f = 1 MHz
0.7
THD
Total Harmonic Distortion
f = 5 MHz, VO = 2 VPP, AV = +2
RL = 1 kΩ to V+/2
–64
VO = 2 VPP, ± 0.1%, AV = −1
35
nV/
pA/
dBc
ts
Settling Time
VOS
Input Offset Voltage
1
5
7
mV
IB
Input Bias Current (Note 7)
−1
−2.6
−3.5
µA
IOS
Input Offset Current
34
800
1800
nA
CMVR
Common Mode Input Voltage
Range
–0.3
−0.2
−0.1
CMRR
Common Mode Rejection Ratio
CMRR ≥ 50 dB
V− ≤ VCM ≤ V+ −1.5V
3
15.0
14.6
15.1
72
90
ns
V
dB
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LMH6640
16V Electrical Characteristics
(Continued)
Unless otherwise specified, All limits guaranteed for TJ = 25˚C, V+ = 16V, V− = 0V, VO = VCM = V+/2 and RL = 2 kΩ to V+/2.
Boldface limits apply at temperature extremes. (Note 9)
Symbol
AVOL
VO
Parameter
Large Signal Voltage Gain
Output Swing High
Conditions
Min
(Note 6)
Typ
(Note 5)
VO = 15 VPP, RL = 2 kΩ to V+/2
86
82
95
VO = 14 VPP, RL = 150Ω to V+/2
74
70
78
15.85
15.90
15.45
15.78
RL = 2 kΩ to V+/2
+
RL = 150Ω to V /2
Output Swing Low
ISC
Output Short Circuit Current
(Note 3)
Max
(Note 6)
dB
RL = 2 kΩ to V+/2
0.10
0.15
RL = 150Ω to V+/2
0.21
0.55
+
Sourcing to V /2
60
30
95
Sinking from V+/2
50
15
75
V
mA
± 100
mA
80
dB
IOUT
Output Current
VO = 0.5V from either Supply
PSRR
Power Supply Rejection Ratio
15V ≤ V+ ≤ 17V
IS
Supply Current
No Load
4
RIN
Common Mode Input
Resistance
AV = +1, f = 1 kHz, RS = 1 MΩ
32
CIN
Common Mode Input
Capacitance
AV = +1, RS = 100 kΩ
1.7
ROUT
Output Resistance Closed Loop RF = 10 kΩ, f = 1 kHz, AV = −1
72
Units
0.1
RF = 10 kΩ, f = 1 MHz, AV = −1
0.3
DG
Differential Gain
NTSC, AV = +2
RL = 150Ω to V+/2
0.12
DP
Differential Phase
NTSC, AV = +2
RL = 150Ω to V+/2
0.12
6.5
7.8
mA
MΩ
pF
Ω
%
deg
Note 1: Absolute maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics.
Note 2: Human body model, 1.5 kΩ in series with 100 pF. Machine Model, 0Ω in series with 200 pF.
Note 3: Applies to both single-supply and split-supply operation. Continuous short circuit operation at elevated ambient temperature can result in exceeding the
maximum allowed junction temperature of 150 ˚C Short circuit test is a momentary test. Output short circuit duration is infinite for VS < 6V at room temperature and
below. For VS > 6V, allowable short circuit duration is 1.5 ms.
Note 4: The maximum power dissipation is a function of TJ(MAX), θJA , and TA. The maximum allowable power dissipation at any ambient temperature is
PD = (TJ(MAX)-TA ) / θJA. All numbers apply for packages soldered directly onto a PC board.
Note 5: Typical Values represent the most likely parametric norm.
Note 6: All limits are guaranteed by testing or statistical analysis.
Note 7: Positive current corresponds to current flowing into the device.
Note 8: Slew rate is the average of the rising and falling slew rates
Note 9: Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of
the device such that TJ = TA. No guarantee of parametric performance is indicated in the electrical tables under conditions of internal self-heating where TJ > TA.
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4
LMH6640
Connection Diagram
5-Pin SOT23
20086223
Top View
Ordering Information
Package
5-Pin SOT23
Part Number
LMH6640MF
LMH6640MFX
Package Marking
Transport Media
1k Units Tape and Reel
AH1A
3k Units Tape and Reel
5
NSC Drawing
MF05A
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LMH6640
Typical Performance Characteristics
At TJ = 25˚C, V+ = 16 V, V− = 0V, RF = 330Ω for AV= +2, RF
= 1 kΩ for AV = −1. RL tied to V /2. Unless otherwise specified.
+
IS vs. VS for Various Temperature
IS vs. VCM for Various Temperature
20086220
20086221
IB vs. VS for Various Temperature
IB vs. VS for Various Temperature
20086218
20086219
VOS vs. VS for Various Temperature
(Typical Unit)
IOS vs. VS for Various Temperature
20086216
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20086227
6
1 kΩ for AV = −1. RL tied to V+/2. Unless otherwise specified. (Continued)
Positive Output Saturation Voltage vs.
VS for Various Temperature
Negative Output Saturation Voltage vs.
VS for Various Temperature
20086224
20086228
Output Sourcing Saturation Voltage vs.
ISOURCING for Various Temperature
Output Sinking Saturation Voltage vs.
ISINKING for Various Temperature
20086230
20086231
Input Current Noise vs. Frequency
Input Voltage Noise vs. Frequency
20086204
20086205
7
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LMH6640
Typical Performance Characteristics At TJ = 25˚C, V+ = 16 V, V− = 0V, RF = 330Ω for AV= +2, RF =
LMH6640
Typical Performance Characteristics At TJ = 25˚C, V+ = 16 V, V− = 0V, RF = 330Ω for AV= +2, RF =
1 kΩ for AV = −1. RL tied to V+/2. Unless otherwise specified. (Continued)
Gain vs. Frequency Normalized
(PIN= −30 dBm)
Gain vs. Frequency Normalized
(PIN=−30dBm)
20086206
20086207
Gain vs. Frequency for Various VS
(PIN = −30 dBm)
Gain vs. Frequency for Various VS
(PIN = −30 dBm)
20086209
20086210
Relative Gain vs. Frequency for Various Temperature
(PIN = −10 dBm)
Open Loop Gain & Phase vs. Frequency for
Various Temperature (PIN = −30 dBm)
20086233
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20086232
8
1 kΩ for AV = −1. RL tied to V+/2. Unless otherwise specified. (Continued)
Large Signal Transition
Large Signal Transition
20086213
20086214
Small Signal Pulse Response
Small Signal Pulse Response
20086215
20086208
Large Signal Pulse Response
Large Signal Pulse Response
20086211
20086212
9
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LMH6640
Typical Performance Characteristics At TJ = 25˚C, V+ = 16 V, V− = 0V, RF = 330Ω for AV= +2, RF =
LMH6640
Typical Performance Characteristics At TJ = 25˚C, V+ = 16 V, V− = 0V, RF = 330Ω for AV= +2, RF =
1 kΩ for AV = −1. RL tied to V+/2. Unless otherwise specified. (Continued)
PSRR vs. Frequency
CMRR vs. Frequency
20086201
20086217
Closed Loop Output Resistance vs. Frequency
Harmonic Distortion
20086203
20086226
0.1 dB Gain Flatness vs. Frequency Normalized
Output Power vs. Input Power (AV = +1)
20086202
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20086229
10
1 kΩ for AV = −1. RL tied to V+/2. Unless otherwise specified. (Continued)
Differential Gain/Phase vs. IRE
20086225
• The sum of all the capacitors and resistors in the R-C
ladder is the total VCOM capacitance and resistance respectively. This total varies from panel to panel; capacitance could range from 50 nF-200 nF and the resistance
could be anywhere from 20Ω-100Ω.
• The number of ladder sections has been reduced to a
number (4 sections in this case) which can easily be put
together in the lab and which behaves reasonably close
to the actual load.
In this example, the LMH6640 was tested under the simulated conditions of total 209 nF capacitance and 54Ω as
shown in Figure 1.
Application Notes
With its high output current and speed, one of the major
applications for the LMH6640 is the VCOM driver in a TFT
panel. This application is a specially taxing one because of
the demands it places on the operational amplifier’s output to
drive a large amount of bi-directional current into a heavy
capacitive load while operating under unity gain condition,
which is a difficult challenge due to loop stability reasons.
For a more detailed explanation of what a TFT panel is and
what its amplifier requirements are, please see the Application Notes section of the LM6584 found on the web at:
http://www.national.com/ds.cgi/LM/LM6584.pdf
Because of the complexity of the TFT VCOM waveform and
the wide variation in characteristics between different TFT
panels, it is difficult to decipher the results of circuit testing in
an actual panel. The ability to make simplifying assumptions
about the load in order to test the amplifier on the bench
allows testing using standard equipment and provides familiar results which could be interpreted using standard loop
analysis techniques. This is what has been done in this
application note with regard to the LMH6640’s performance
when subjected to the conditions found in a TFT VCOM
application.
Figure 1, shows a typical simplified VCOM application with
the LMH6640 buffering the VCOM potential (which is usually
around 1⁄2 of panel supply voltage) and looking into the
simplified model of the load. The load represents the cumulative effect of all stray capacitances between the VCOM
node and both row and column lines. Associated with the
capacitances shown, is the distributed resistance of the lines
to each individual transistor switch. The other end of this R-C
ladder is driven by the column driver in an actual panel and
here is driven with a low impedance MOSFET driver (labeled
“High Current Driver”) for the purposes of this bench test to
simulate the effect that the column driver exerts on the VCOM
load.
The modeled TFT VCOM load, shown in Figure 1, is based on
the following simplifying assumptions in order to allow for
easy bench testing and yet allow good matching results
obtained in the actual application:
20086235
FIGURE 1. LMH6640 in a VCOM Buffer Application with
Simulated TFT Load
RS is sometimes used in the panel to provide additional
isolation from the load while RF2 provides a more direct
feedback from the VCOM. RF1, RF2, and RS are trimmed in
the actual circuit with settling time and stability trade-offs
considered and evaluated. When tested under simulated
load conditions of Figure 1, here are the resultant voltage
and current waveforms at the LMH6640 output:
11
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LMH6640
Typical Performance Characteristics At TJ = 25˚C, V+ = 16 V, V− = 0V, RF = 330Ω for AV= +2, RF =
LMH6640
Application Notes
(Continued)
20086236
FIGURE 2. VCOM Output, High Current Drive Waveform, & LMH6640 Output Current Waveforms
20086237
FIGURE 3. Expanded View of Figure 2 Waveforms showing LMH6640 Current Sinking 1⁄2 Cycle
combination of all these features is not readily available in
the market, especially in the space saving SOT23-5 package. All this performance is achieved at the low power consumption of 65 mW which is of utmost importance in today’s
battery driven TFT panels.
As can be seen, the LMH6640 is capable of supplying up to
160 mA of output current and can settle the output in 4.4 µs.
The LMH6640 is a cost effective amplifier for use in the TFT
VCOM application and is made even more attractive by its
large supply voltage range and high output current. The
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12
inches (millimeters)
5-Pin SOT23
NS Product Number MF05A
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.
For the most current product information visit us at www.national.com.
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LMH6640 TFT-LCD Single, 16V Rail-to-Rail High Output Operational Amplifier
Physical Dimensions
unless otherwise noted