LF198QML [TI]

LF198QML Monolithic Sample-and-Hold Circuits; LF198QML单片采样保持电路
LF198QML
型号: LF198QML
厂家: TEXAS INSTRUMENTS    TEXAS INSTRUMENTS
描述:

LF198QML Monolithic Sample-and-Hold Circuits
LF198QML单片采样保持电路

采样保持电路
文件: 总20页 (文件大小:994K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
LF198QML  
LF198QML Monolithic Sample-and-Hold Circuits  
Literature Number: SNOSAH9  
February 2005  
LF198QML  
Monolithic Sample-and-Hold Circuits  
General Description  
Features  
n Operates from 5V to 18V supplies  
n Less than 10 µs acquisition time  
n TTL, PMOS, CMOS compatible logic input  
n 0.5 mV typical hold step at Ch = 0.01 µF  
n Low input offset  
The LF198 is a monolithic sample-and-hold circuit which  
utilizes BI-FET technology to obtain ultra-high dc accuracy  
with fast acquisition of signal and low droop rate. Operating  
as a unity gain follower, dc gain accuracy is 0.002% typical  
and acquisition time is as low as 6 µs to 0.01%. A bipolar  
input stage is used to achieve low offset voltage and wide  
bandwidth. Input offset adjust is accomplished with a single  
pin, and does not degrade input offset drift. The wide band-  
width allows the LF198 to be included inside the feedback  
loop of 1 MHz op amps without having stability problems.  
Input impedance of 1010allows high source impedances to  
be used without degrading accuracy.  
n 0.002% gain accuracy  
n Low output noise in hold mode  
n Input characteristics do not change during hold mode  
n High supply rejection ratio in sample or hold  
n Wide bandwidth  
Logic inputs on the LF198 are fully differential with low input  
current, allowing direct connection to TTL, PMOS, and  
CMOS. Differential threshold is 1.4V. The LF198 will operate  
from 5V to 18V supplies.  
P-channel junction FET’s are combined with bipolar devices  
in the output amplifier to give droop rates as low as 5 mV/min  
with a 1 µF hold capacitor. The JFET’s have much lower  
noise than MOS devices used in previous designs and do  
not exhibit high temperature instabilities. The overall design  
guarantees no feed-through from input to output in the hold  
mode, even for input signals equal to the supply voltages.  
Ordering Information  
NSC Part Number  
JAN Part Number  
5962–8760801GA  
5962–8760801VZA  
5962–8760801QZA  
NSC Package Number  
H08C  
Package Description  
8LD Metal Can  
LF198H/883  
LF198WG-QMLV  
LF198WG/883  
WG14A  
14LD Ceramic SOIC  
14LD Ceramic SOIC  
WG14A  
Connection Diagrams  
Small-Outline Package  
Metal Can Package  
20122215  
See NS Package Number WG14A  
20122214  
See NS Package Number H08C  
© 2005 National Semiconductor Corporation  
DS201222  
www.national.com  
Typical Connection and Performance Curve  
Acquisition Time  
20122232  
20122216  
Functional Diagram  
20122201  
www.national.com  
2
Absolute Maximum Ratings (Note 1)  
Supply Voltage  
18V  
500 mW  
Power Dissipation (Package Limitation) (Note 2)  
Operating Ambient Temperature Range  
−55˚C to +125˚C  
+150˚C  
Maximum Junction Temperature (TJmax  
Input Voltage  
)
Equal to Supply Voltage  
+7V, 30V  
Logic To Logic Reference Differential Voltage (Note 3)  
Output Short Circuit Duration  
Hold Capacitor Short Circuit Duration  
Lead Temperature (Soldering, 10 sec.)  
Thermal Resistance  
Indefinite  
10 sec  
260˚C  
θJA  
@
Metal Can (Still Air 0.5W)  
160˚C/W  
84˚C/W  
140˚C/W  
95˚C/W  
@
Metal Can (500 LF/Min Air Flow 0.5W)  
@
Ceramic SOIC (Still Air 0.5W)  
@
Ceramic SOIC (500 LF/Min Air Flow 0.5W)  
θJC  
Metal Can  
48˚C/W  
20˚C/W  
Ceramic SOIC  
Package Weight (typical)  
Metal Can  
TBD  
415mg  
500V  
Ceramic SOIC  
ESD Tolerance (Note 7)  
Quality Conformance Inspection  
Mil-Std-883, Method 5005 — Group A  
Subgroup  
Description  
Temperature (˚C)  
+25˚C  
1
2
Static tests at  
Static tests at  
+125˚C  
−55˚C  
3
Static tests at  
4
Dynamic tests at  
Dynamic tests at  
Dynamic tests at  
Functional tests at  
Functional tests at  
Functional tests at  
Switching tests at  
Switching tests at  
Switching tests at  
+25˚C  
5
+125˚C  
−55˚C  
6
7
+25˚C  
8A  
8B  
9
+125˚C  
−55˚C  
+25˚C  
10  
11  
+125˚C  
−55˚C  
3
www.national.com  
Electrical Characteristics  
The following specifications apply unless otherwise specified. VCC  
erence Pin = 0V, Logic Pin = 4V  
=
15V, RL = 10K, VIN = 0V, CHOLD = 0.01 µF, Logic Ref-  
Sub-  
Symbol  
ICC+  
Parameter  
Conditions  
Notes  
Min Max  
Unit  
groups  
1, 2  
3
Positive Supply Current  
5.5  
6.5  
mA  
mA  
mA  
mA  
mA  
mA  
mA  
mA  
mA  
mA  
mA  
mA  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
nA  
+VCC = 15V, -VCC = -15V  
5.5  
1, 2  
3
+VCC = 18V, -VCC = -18V,  
Mode = "Sample"  
6.5  
5.5  
1, 2  
3
+VCC = 18V, -VCC = -18V,  
Mode = "Hold"  
6.5  
ICC  
-
Negative Supply Current  
-5.5  
-6.5  
-5.5  
-6.5  
-5.5  
-6.5  
1, 2  
3
+VCC = 15V, -VCC = -15V  
1, 2  
3
+VCC = 18V, -VCC = -18V,  
Mode = "Sample"  
1, 2  
3
+VCC = 18V, -VCC = -18V,  
Mode = "Hold"  
VOS  
Input Offset Voltage  
-3.0  
-5.0  
-3.0  
-5.0  
-3.0  
-5.0  
-3.0  
-5.0  
-3.0  
-5.0  
-3.0  
-5.0  
-3.0  
-5.0  
-3.0  
-5.0  
-25  
3.0  
5.0  
3.0  
5.0  
3.0  
5.0  
3.0  
5.0  
3.0  
5.0  
3.0  
5.0  
3.0  
5.0  
3.0  
5.0  
25  
1
+VCC = 3V, -VCC = -7V  
2, 3  
1
+VCC = 15V, -VCC = -15V  
+VCC = 3.5V, -VCC = -26.5V  
+VCC = 18V, -VCC = -18V  
+VCC = 3.5V, -VCC = -32.5V  
+VCC = 26.5V, -VCC = -3.5V  
2, 3  
1
2, 3  
1
2, 3  
1
2, 3  
1
2, 3  
1
+VCC = 32.5V, -VCC = -3.5V,  
Logic = 2.5V  
2, 3  
1
+VCC = 7V, -VCC = -3V  
+VCC = 3V, -VCC = -7V  
+VCC = 15V, -VCC = -15V  
+VCC = 3.5V, -VCC = -32.5V  
+VCC = 32.5V, -VCC = -3.5V  
+VCC = 7V, -VCC = -3V  
2, 3  
1
IIB  
Input Bias Current  
-75  
75  
nA  
2, 3  
1
-25  
25  
nA  
-75  
75  
nA  
2, 3  
1
-25  
25  
nA  
-75  
75  
nA  
2, 3  
1
-25  
25  
nA  
-75  
75  
nA  
2, 3  
1
-25  
25  
nA  
-75  
75  
nA  
2, 3  
1
ILeak(Cap)  
Leakage Current into Hold  
Capacitor  
+VCC = 3V, -VCC = -7V  
(Note 5)  
(Note 5)  
-100 100  
-100 100  
-100 100  
-100 100  
pA  
+VCC = 3.5V, -VCC = -32.5V  
+VCC = 32.5V, -VCC = -3.5V  
+VCC = 7V, -VCC = -3V  
pA  
1
pA  
1
pA  
1
www.national.com  
4
Electrical Characteristics (Continued)  
The following specifications apply unless otherwise specified. VCC  
erence Pin = 0V, Logic Pin = 4V  
=
15V, RL = 10K, VIN = 0V, CHOLD = 0.01 µF, Logic Ref-  
Sub-  
groups  
1
Symbol  
VHS  
Parameter  
Conditions  
Notes  
Min Max  
Unit  
Hold Step  
(Note 4)  
-2.0  
-5.6  
-2.5  
-5.6  
-2.5  
-5.6  
2.0  
5.6  
mV  
mV  
mV  
mV  
mV  
mV  
%
+VCC = 15V -VCC = -15V  
+VCC = 3.5V, -VCC = -26.5V  
+VCC = 26.5V, -VCC = -3.5V  
+VCC = 7V, -VCC = -3V  
2, 3  
1
(Note 4)  
(Note 4)  
2.5  
5.6  
2, 3  
1
2.5  
5.6  
2, 3  
1
AE  
Gain Error  
0.02  
0.06  
0.005  
0.02  
0.005  
0.06  
0.005  
0.02  
%
2, 3  
1
%
+VCC = 3.5V, -VCC = -26.5V  
+VCC = 32.5V, -VCC = -3.5V  
+VCC = 26.5V, -VCC = -3.5V  
+VCC = 8V, -VCC = -28V  
+VCC = 28V, -VCC = -8V  
+VCC = 18V, -VCC = -18V  
+VCC = 8V, -VCC = -28V  
+VCC = 28V, -VCC = -8V  
%
2, 3  
1
%
%
2, 3  
1
%
%
2, 3  
1
ZI  
Input Impedance  
10.0  
0.8  
GΩ  
GΩ  
GΩ  
GΩ  
2, 3  
1
10.0  
0.8  
2, 3  
1
ZO  
Output Impedance  
2.0  
4.0  
-4.5  
-3.0  
25  
2, 3  
1
ICharge  
Capacitor Charging Current  
-25  
-25  
4.5  
3.0  
mA  
mA  
mA  
mA  
2, 3  
1
25  
2, 3  
Logic  
VOS  
Logic Pin Current  
+VCC = 18V, -VCC = -18V,  
10  
µA  
1, 2, 3  
Mode = "Sample", Logic = 7V  
1.0  
0.5  
3.5  
6.0  
1.1  
2.0  
20  
µA  
µA  
1
2, 3  
1
+VCC = 18V, -VCC = -18V,  
Mode = "Hold", Logic = -30V  
Input Offset Voltage  
-3.5  
-6.0  
-1.1  
-2.0  
7.0  
mV  
mV  
mV  
mV  
mA  
mA  
µA  
+VCC = 15V, -VCC = -15V,  
IDrive = +1mA  
2, 3  
1
Delta VOS Input Offset Voltage  
+VCC = 15V, -VCC = -15V,  
IDrive = +1mA to -1mA  
2, 3  
1
IOS  
IOS  
+
-
Output Short Circuit Current  
Output Short Circuit Current  
Logic Reference Pin Current  
+VCC = 18V, -VCC = -18V  
+VCC = 18V, -VCC = -18V  
-25  
-7.0  
1.0  
5.0  
1
ILogicRef  
PSRR  
FTRR  
VTH  
-1.0  
-0.5  
1
+VCC = 18V, -VCC = -18V,  
Mode = "Sample", Logic = 7V  
µA  
2, 3  
+VCC = 18V, -VCC = -18V,  
Mode = "Hold", Logic = -30V  
10  
µA  
1, 2, 3  
Power Supply Rejection Ratio  
Feed Through Rejection Ratio  
Differential Logic Level  
80  
74  
80  
74  
86  
74  
86  
74  
0.8  
dB  
dB  
dB  
dB  
dB  
dB  
dB  
dB  
V
1
2, 3  
1
+VCC = 10V, -VCC = -15V  
+VCC = 15V, -VCC = -10V  
+VCC = 3.5V, -VCC = -32.5V  
+VCC = 32.5V, -VCC = -3.5V  
2, 3  
1
2, 3  
1
2, 3  
1
(Note 8)  
2.4  
5
www.national.com  
Electrical Characteristics (Continued)  
The following specifications apply unless otherwise specified. VCC  
erence Pin = 0V, Logic Pin = 4V  
=
15V, RL = 10K, VIN = 0V, CHOLD = 0.01 µF, Logic Ref-  
Sub-  
groups  
1
Symbol  
Parameter  
2nd Stage VOS  
Conditions  
Notes  
Min Max  
Unit  
VOS  
(2nd Stg)  
-35  
-50  
-35  
-50  
-35  
-50  
-35  
-50  
+35  
+50  
+35  
+50  
+35  
+50  
+35  
+50  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
mV  
+VCC = 3.5V, -VCC = -32.5V  
+VCC = 3V, -VCC = -7V  
2, 3  
1
2, 3  
1
+VCC = 32.5V, -VCC = -3.5V  
+VCC = 7V, -VCC = -3V  
2, 3  
1
2, 3  
AC Parameters  
The following specifcations apply unless otherwise specified. VCC  
ence Pin = 0V, Logic Pin = 4V  
=
15V, RL = 10K, VIN = 0V, CHold = 0.01 µF, Logic Refer-  
Sub-  
groups  
Symbol  
TAQ  
Parameter  
Acquisition Time  
Conditions  
Delta VOUT = 10V,  
Notes  
Min Max  
Unit  
µS  
6.0  
25  
4
CHold = 1000pF  
Delta VOUT = 10V,  
CHold = 0.01µF  
µS  
4
DC Parameters: Drift Values  
The following conditions apply to all the following parameters, unless otherwise specified. VCC  
=
15V, RL = 10K, VIN = 0V,  
CHold = 0.01 µF, Logic Reference Pin = 0V, Logic Pin = 4V Deltas required for S-Level product ONLY.  
Sub-  
groups  
Symbol  
Parameters  
Conditions  
Notes  
Min Max  
Unit  
VOS  
IIB  
Input Offset Voltage  
Input Bias Current  
+VCC = 15V, -VCC = -15V  
+VCC = 15V, -VCC = -15V  
-0.5  
-2.5  
0.5  
2.5  
mV  
nA  
1
1
Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is  
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed  
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test  
conditions  
Note 2: The maximum power dissipation must be derated at elevated temperatures and is dictated by T  
, θ , and the ambient temperature, T . The maximum  
A
JMAX JA  
allowable power dissipation at any temperature is P = (T  
− T )/θ , or the number given in the Absolute Maximum Ratings, whichever is lower. .  
D
JMAX  
A JA  
Note 3: Although the differential voltage may not exceed the limits given, the common-mode voltage on the logic pins may be equal to the supply voltages without  
causing damage to the circuit. For proper logic operation, however, one of the logic pins must always be at least 2V below the positive supply and 3V above the  
negative supply.  
Note 4: Hold step is sensitive to stray capacitive coupling between input logic signals and the hold capacitor. 1 pF, for instance, will create an additional 0.5 mV step  
with a 5V logic swing and a 0.01µF hold capacitor. Magnitude of the hold step is inversely proportional to hold capacitor value.  
Note 5: Leakage current is measured at a junction temperature of 25˚C. The effects of junction temperature rise due to power dissipation or elevated ambient can  
be calculated by doubling the 25˚C value for each 11˚C increase in chip temperature. Leakage is guaranteed over full input signal range.  
Note 6: See Definition of Terms  
Note 7: Human body model, 100pF discharged through 1.5KΩ  
Note 8: Parameter tested go no go only for Vth test.  
www.national.com  
6
Typical Performance Characteristics  
Aperture Time  
Dielectric Absorption  
Error in Hold Capacitor  
(Note 6)  
20122217  
20122218  
Dynamic Sampling Error  
Output Droop Rate  
20122219  
20122220  
“Hold” Settling Time  
Hold Step  
(Note 6)  
20122221  
20122222  
7
www.national.com  
Typical Performance Characteristics (Continued)  
Leakage Current into Hold  
Capacitor  
Phase and Gain (Input to  
Output, Small Signal)  
20122223  
20122224  
Gain Error  
Power Supply Rejection  
20122226  
20122225  
Output Short Circuit Current  
Output Noise  
20122227  
20122228  
Note 9: See Definition  
www.national.com  
8
Typical Performance Characteristics (Continued)  
Feedthrough Rejection Ratio  
(Hold Mode)  
Input Bias Current  
20122230  
20122229  
Output Transient at Start  
of Sample Mode  
Hold Step vs Input Voltage  
20122231  
20122212  
Output Transient at Start  
of Hold Mode  
20122213  
9
www.national.com  
Logic Input Configurations  
TTL & CMOS  
3V VLOGIC (Hi State) 7V  
20122233  
Threshold = 1.4V  
20122234  
Threshold = 1.4V*Select for 2.8V at pin 8  
CMOS  
7V VLOGIC (Hi State) 15V  
20122235  
+
Threshold = 0.6 (V ) + 1.4V  
20122236  
+
Threshold = 0.6 (V ) − 1.4V  
Op Amp Drive  
20122237  
Threshold +4V  
20122238  
Threshold = −4V  
www.national.com  
10  
In addition, although the output may have settled, the hold  
capacitor has an additional lag due to the 300series  
resistor on the chip. This means that at the moment the  
“hold” command arrives, the hold capacitor voltage may be  
somewhat different than the actual analog input. The effect  
of these delays is opposite to the effect created by delays in  
the logic which switches the circuit from sample to hold. For  
example, consider an analog input of 20 Vp-p at 10 kHz.  
Maximum dV/dt is 0.6 V/µs. With no analog phase delay and  
100 ns logic delay, one could expect up to (0.1 µs) (0.6V/µs)  
= 60 mVerror if the “hold” signal arrived near maximum dV/dt  
of the input. A positive-going input would give a +60 mV  
error. Now assume a 1 MHz (3 dB) bandwidth for the overall  
analog loop. This generates a phase delay of 160 ns. If the  
hold capacitor sees this exact delay, then error due to analog  
delay will be (0.16 µs) (0.6 V/µs) = −96 mV. Total output error  
is +60 mV (digital) −96 mV (analog) for a total of −36 mV. To  
add to the confusion, analog delay is proportioned to hold  
capacitor value while digital delay remains constant. A family  
of curves (dynamic sampling error) is included to help esti-  
mate errors.  
Application Hints  
HOLD CAPACITOR  
Hold step, acquisition time, and droop rate are the major  
trade-offs in the selection of a hold capacitor value. Size and  
cost may also become important for larger values. Use of the  
curves included with this data sheet should be helpful in  
selecting a reasonable value of capacitance. Keep in mind  
that for fast repetition rates or tracking fast signals, the  
capacitor drive currents may cause a significant temperature  
rise in the LF198.  
A significant source of error in an accurate sample and hold  
circuit is dielectric absorption in the hold capacitor. A mylar  
cap, for instance, may “sag back” up to 0.2% after a quick  
change in voltage. A long sample time is required before the  
circuit can be put back into the hold mode with this type of  
capacitor. Dielectrics with very low hysteresis are polysty-  
rene, polypropylene, and Teflon. Other types such as mica  
and polycarbonate are not nearly as good. The advantage of  
polypropylene over polystyrene is that it extends the maxi-  
mum ambient temperature from 85˚C to 100˚C. Most ce-  
A curve labeled Aperture Time has been included for sam-  
pling conditions where the input is steady during the sam-  
pling period, but may experience a sudden change nearly  
coincident with the “hold” command. This curve is based on  
a 1 mV error fed into the output.  
>
ramic capacitors are unusable with  
1% hysteresis. Ce-  
ramic “NPO” or “COG” capacitors are now available for  
125˚C operation and also have low dielectric absorption. For  
more exact data, see the curve Dielectric Absorption Error.  
The hysteresis numbers on the curve are final values, taken  
after full relaxation. The hysteresis error can be significantly  
reduced if the output of the LF198 is digitized quickly after  
the hold mode is initiated. The hysteresis relaxation time  
constant in polypropylene, for instance, is 1050 ms. If  
A-to-D conversion can be made within 1 ms, hysteresis error  
will be reduced by a factor of ten.  
A second curve, Hold Settling Time indicates the time re-  
quired for the output to settle to 1 mV after the “hold”  
command.  
DIGITAL FEEDTHROUGH  
Fast rise time logic signals can cause hold errors by feeding  
externally into the analog input at the same time the amplifier  
is put into the hold mode. To minimize this problem, board  
layout should keep logic lines as far as possible from the  
analog input and the Ch pin. Grounded guarding traces may  
also be used around the input line, especially if it is driven  
from a high impedance source. Reducing high amplitude  
logic signals to 2.5V will also help.  
DC AND AC ZEROING  
DC zeroing is accomplished by connecting the offset adjust  
pin to the wiper of a 1 kpotentiometer which has one end  
tied to V+ and the other end tied through a resistor to ground.  
The resistor should be selected to give 0.6 mA through the  
1k potentiometer.  
Guarding Technique  
AC zeroing (hold step zeroing) can be obtained by adding an  
inverter with the adjustment pot tied input to output. A 10 pF  
capacitor from the wiper to the hold capacitor will give 4 mV  
hold step adjustment with a 0.01 µF hold capacitor and 5V  
logic supply. For larger logic swings, a smaller capacitor  
<
(
10 pF) may be used.  
LOGIC RISE TIME  
For proper operation, logic signals into the LF198 must have  
a minimum dV/dt of 1.0 V/µs. Slower signals will cause  
excessive hold step. If a R/C network is used in front of the  
logic input for signal delay, calculate the slope of the wave-  
form at the threshold point to ensure that it is at least  
1.0 V/µs.  
SAMPLING DYNAMIC SIGNALS  
Sample error to moving input signals probably causes more  
confusion among sample-and-hold users than any other pa-  
rameter. The primary reason for this is that many users make  
the assumption that the sample and hold amplifier is truly  
locked on to the input signal while in the sample mode. In  
actuality, there are finite phase delays through the circuit  
creating an input-output differential for fast moving signals.  
20122205  
Use 10-pin layout. Guard around Chis tied to output.  
11  
www.national.com  
Typical Applications  
Sample and Difference Circuit  
X1000 Sample & Hold  
(Output Follows Input in Hold Mode)  
20122240  
V
= V + V (HOLD MODE)  
B IN  
OUT  
20122239  
*For lower gains, the LM108 must be frequency compensated  
Ramp Generator with Variable Reset Level  
Integrator with Programmable Reset Level  
20122242  
20122243  
www.national.com  
12  
Typical Applications (Continued)  
Output Holds at Average of Sampled Input  
Increased Slew Current  
20122246  
20122247  
Reset Stabilized Amplifier (Gain of 1000)  
Fast Acquisition, Low Droop Sample & Hold  
20122249  
20122250  
13  
www.national.com  
Typical Applications (Continued)  
Synchronous Correlator for Recovering  
Signals Below Noise Level  
2–Channel Switch  
20122253  
20122252  
A
B
Gain  
ZIN  
1
1010  
0.02%  
1
0.2%  
47 kΩ  
BW  
. 1 MHz  
. 400 kHz  
−90 dB  
Crosstalk −90 dB  
@
1 kHz  
Offset  
6 mV  
75 mV  
DC & AC Zeroing  
Staircase Generator  
20122255  
*Select for step height  
20122259  
50k  
1V Step  
www.national.com  
14  
Typical Applications (Continued)  
Differential Hold  
Capacitor Hysteresis Compensation  
20122256  
20122257  
**Adjust for amplitude  
Hold Settling Time: The time required for the output to  
settle within 1 mV of final value after the “hold” logic com-  
mand.  
Definition of Terms  
Hold Step: The voltage step at the output of the sample and  
hold when switching from sample mode to hold mode with a  
steady (dc) analog input voltage. Logic swing is 5V.  
Dynamic Sampling Error: The error introduced into the  
held output due to a changing analog input at the time the  
hold command is given. Error is expressed in mV with a  
given hold capacitor value and input slew rate. Note that this  
error term occurs even for long sample times.  
Acquisition Time: The time required to acquire a new ana-  
log input voltage with an output step of 10V. Note that  
acquisition time is not just the time required for the output to  
settle, but also includes the time required for all internal  
nodes to settle so that the output assumes the proper value  
when switched to the hold mode.  
Aperture Time: The delay required between “Hold” com-  
mand and an input analog transition, so that the transition  
does not affect the held output.  
Gain Error: The ratio of output voltage swing to input volt-  
age swing in the sample mode expressed as a per cent  
difference.  
15  
www.national.com  
Revision History Section  
Date  
Revision  
Released  
Section  
New release, Corporate format  
Originator  
Changes  
02/25/05  
A
L. Lytle  
1 MDS converted to corp. datasheet  
format. MNLF198–X Rev 3B0 MDS to be  
archived. Change has been made to  
Electrical Section, Parameter IOS- . Max  
limit was 7.0 now is −7.0 confirmed with  
SG. Added note Parameter tested go no  
go to VTH test.  
www.national.com  
16  
Physical Dimensions inches (millimeters) unless otherwise noted  
Metal Can Package (H)  
NS Package Number H08C  
14 LD Ceramic SOIC (WG)  
NS Package Number WG14A  
17  
www.national.com  
Notes  
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.  
LIFE SUPPORT POLICY  
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS  
WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR  
CORPORATION. As used herein:  
1. Life support devices or systems are devices or systems  
which, (a) are intended for surgical implant into the body, or  
(b) support or sustain life, and whose failure to perform when  
properly used in accordance with instructions for use  
provided in the labeling, can be reasonably expected to result  
in a significant injury to the user.  
2. A critical component is any component of a life support  
device or system whose failure to perform can be reasonably  
expected to cause the failure of the life support device or  
system, or to affect its safety or effectiveness.  
BANNED SUBSTANCE COMPLIANCE  
National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products  
Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain  
no ‘‘Banned Substances’’ as defined in CSP-9-111S2.  
National Semiconductor  
Americas Customer  
Support Center  
National Semiconductor  
Europe Customer Support Center  
Fax: +49 (0) 180-530 85 86  
National Semiconductor  
Asia Pacific Customer  
Support Center  
National Semiconductor  
Japan Customer Support Center  
Fax: 81-3-5639-7507  
Email: new.feedback@nsc.com  
Tel: 1-800-272-9959  
Email: europe.support@nsc.com  
Deutsch Tel: +49 (0) 69 9508 6208  
English Tel: +44 (0) 870 24 0 2171  
Français Tel: +33 (0) 1 41 91 8790  
Email: ap.support@nsc.com  
Email: jpn.feedback@nsc.com  
Tel: 81-3-5639-7560  
www.national.com  
IMPORTANT NOTICE  
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,  
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should  
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are  
sold subject to TIs terms and conditions of sale supplied at the time of order acknowledgment.  
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TIs standard  
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where  
mandated by government requirements, testing of all parameters of each product is not necessarily performed.  
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and  
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide  
adequate design and operating safeguards.  
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,  
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information  
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a  
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual  
property of the third party, or a license from TI under the patents or other intellectual property of TI.  
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied  
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive  
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional  
restrictions.  
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all  
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not  
responsible or liable for any such statements.  
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably  
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing  
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and  
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products  
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be  
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in  
such safety-critical applications.  
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are  
specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military  
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at  
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.  
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are  
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated  
products in automotive applications, TI will not be responsible for any failure to meet such requirements.  
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:  
Products  
Audio  
Applications  
www.ti.com/audio  
amplifier.ti.com  
dataconverter.ti.com  
www.dlp.com  
Communications and Telecom www.ti.com/communications  
Amplifiers  
Data Converters  
DLP® Products  
DSP  
Computers and Peripherals  
Consumer Electronics  
Energy and Lighting  
Industrial  
www.ti.com/computers  
www.ti.com/consumer-apps  
www.ti.com/energy  
dsp.ti.com  
www.ti.com/industrial  
www.ti.com/medical  
www.ti.com/security  
Clocks and Timers  
Interface  
www.ti.com/clocks  
interface.ti.com  
logic.ti.com  
Medical  
Security  
Logic  
Space, Avionics and Defense www.ti.com/space-avionics-defense  
Transportation and Automotive www.ti.com/automotive  
Power Mgmt  
Microcontrollers  
RFID  
power.ti.com  
microcontroller.ti.com  
www.ti-rfid.com  
Video and Imaging  
www.ti.com/video  
OMAP Mobile Processors www.ti.com/omap  
Wireless Connectivity www.ti.com/wirelessconnectivity  
TI E2E Community Home Page  
e2e.ti.com  
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265  
Copyright © 2011, Texas Instruments Incorporated  

相关型号:

LF198QML-SP

Monolithic Sample-and-Hold Circuits
TI

LF198QML_14

Monolithic Sample-and-Hold Circuits
TI

LF198WG-MLS

SAMPLE AND HOLD AMPLIFIER, 20us ACQUISITION TIME, CDSO14, CERAMIC, SOIC-14
NSC

LF198WG-QMLV

LF198QML Monolithic Sample-and-Hold Circuits
TI

LF198WG/883

LF198QML Monolithic Sample-and-Hold Circuits
TI

LF1OX

PATCHCORD 1/4" ORANGE 1FT
ETC

LF1PX

PATCHCORD 1/4" PURPLE 1FT
ETC

LF1RX

PATCHCORD 1/4" RED 1FT
ETC

LF1S009

SINGLE RJ45 CONNECTOR MODULE WITH INTEGRATED 10 BASE T MAGNETICS & FILTERS
BOTHHAND

LF1S021

SINGLE RJ45 CONNECTOR MODULE WITH INTEGRATED 10 BASE T MAGNETICS & FILTERS
BOTHHAND

LF1S021-43

SINGLE RJ45 CONNECTOR MODULE WITH INTEGRATED 10 BASE T MAGNETICS & FILTER AND LEDS
BOTHHAND

LF1S022

SINGLE RJ45 CONNECTOR MODULE WITH INTEGRATED 10 BASE T MAGNETICS & FILTERS
BOTHHAND