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LMH6642/6643/6644 3V, Low Power, 130MHz, 75mA Rail-to-Rail Output Amplifiers
December 2001
LMH6642/6643/6644 3V, Low Power, 130MHz, 75mA Rail-to-Rail Output Amplifiers
General Description
The LMH664X family true single supply voltage feedback amplifiers offer high speed (130MHz), low distortion (-62dBc), and exceptionally high output current (approximately 75mA) at low cost and with reduced power consumption when compared against existing devices with similar performance. Input common mode voltage range extends to 0.5V below V- and 1V from V+. Output voltage range extends to within 40mV of either supply rail, allowing wide dynamic range especially desirable in low voltage applications. The output stage is capable of approximately 75mA in order to drive heavy loads. Fast output Slew Rate (130V/s) ensures large peak-to-peak output swings can be maintained even at higher speeds, resulting in exceptional full power bandwidth of 40MHz with a 3V supply. These characteristics, along with low cost, are ideal features for a multitude of industrial and commercial applications. 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 (0.1dB gain flatness up the 12MHz under 150 load and AV = +2) with minimal peaking (typically 2dB maximum) for any gain setting and under both heavy and light loads. This along with fast settling time (68ns) and low distortion allows the device to operate well in ADC buffer, and high frequency filter applications as well as other applications. This device family offers professional quality video performance with low DG (0.01%) and DP (0.01) characteristics. Differential Gain and Differential Phase characteristics are also well maintained under heavy loads (150) and throughout the output voltage range. The LMH664X family is offered in single (LMH6642), dual (LMH6643), and quad (LMH6644) options. See ordering information for packages offered.
Features
(VS = 5V, TA = 25C, RL = 2k, AV = +1. Typical values unless specified). n -3dB BW (AV = +1) 130MHz n Supply voltage range 3V to 12.8V n Slew rate (Note 8), (AV = -1) 130V/s n Supply current (no load) 2.7mA/amp n Output short circuit current +115mA/-145mA 75mA n Linear output current n Input common mode volt. 0.5V beyond V-, 1V from V+ n Output voltage swing 40mV from rails n Input voltage noise (100kHz) 17nV/ n Input current noise (100kHz) 0.9pA/ n THD (5MHz, RL = 2k, VO = 2VPP, AV = +2) -62dBc n Settling time 68ns n Fully characterized for 3V, 5V, and 5V n Overdrive recovery 100ns n Output short circuit protected (Note 11) n No output phase reversal with CMVR exceeded
Applications
n n n n n Active filters CD/DVD ROM ADC buffer amp Portable video Current sense buffer
Closed Loop Gain vs. Frequency for Various Gain
Large Signal Frequency Response
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(c) 2001 National Semiconductor Corporation
DS200185
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LMH6642/6643/6644
Absolute Maximum Ratings
(Note 1)
Infrared or Convection Reflow(20 sec) Wave Soldering Lead Temp.(10 sec)
235C 260C
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. ESD Tolerance VIN Differential Output Short Circuit Duration Supply Voltage (V - V ) Voltage at Input/Output pins Input Current Storage Temperature Range Junction Temperature (Note 4) Soldering Information
+ -
2KV (Note 2) 200V (Note 9)
Operating Ratings (Note 1)
Supply Voltage (V+ - V-) Junction Temperature Range (Note 4) Package Thermal Resistance (Note 4) SOT23-5 SOIC-8 MSOP-8 SOIC-14 TSSOP-14 265C/W 190C/W 235C/W 145C/W 155C/W 3V to 12.8V -40C to +85C
2.5V
(Note 3), (Note 11) 13.5V V+ +0.8V, V- -0.8V
10mA
-65C to +150C +150C
3V Electrical Characteristics
Unless otherwise specified, all limits guaranteed for at TJ = 25C, V+ = 3V, V- = 0V, VCM = VO = V+/2, and RL = 2k to V+/2. Boldface limits apply at the temperature extremes. Symbol BW BW0.1dB PBW en in THD DG -3dB BW 0.1dB Gain Flatness Full Power Bandwidth Input-Referred Voltage Noise Input-Referred Current Noise Total Harmonic Distortion Differential Gain Parameter Conditions AV = +1, VOUT = 200mVPP AV = +2, -1, VOUT = 200mVPP AV = +2, RL = 150 to V+/2, RL = 402, VOUT = 200mVPP AV = +1, -1dB, VOUT = 1VPP f = 100kHz f = 1kHz f = 100kHz f = 1kHz f = 5MHz, VO = 2VPP, AV = -1, RL = 100 to V+/2 VCM = 1V, NTSC, AV = +2 RL =150 to V+/2 RL =1k to V+/2 DP Differential Phase VCM = 1V, NTSC, AV = +2 RL =150 to V+/2 RL =1k to V+/2 CT Rej. TS SR VOS TC VOS IB IOS RIN CIN Cross-Talk Rejection Settling Time Slew Rate (Note 8) Input Offset Voltage Input Offset Average Drift Input Bias Current Input Offset Current Common Mode Input Resistance Common Mode Input Capacitance
2
Min (Note 6) 80
Typ (Note 5) 115 46 19 40 17 48 0.90 3.3 -48 0.17
Max (Note 6)
Units
MHz MHz MHz nV/ pA/ dBc
% 0.03 0.05 deg 0.03 47 68 90 120 dB ns V/s
f = 5MHz, Receiver: Rf = Rg = 510, AV = +2 VO = 2VPP, 0.1%, 8pF Load, VS = 5V AV = -1, VI = 2VPP
1
(Note 12) (Note 7)
5 7
-2.60 -3.25 800 1000
mV V/C A nA M pF
5
-1.50 20 3 2
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LMH6642/6643/6644
3V Electrical Characteristics
Symbol CMVR Parameter Input Common-Mode Voltage Range
(Continued) Unless otherwise specified, all limits guaranteed for at TJ = 25C, V+ = 3V, V- = 0V, VCM = VO = V+/2, and RL = 2k to V+/2. Boldface limits apply at the temperature extremes. Conditions CMRR 50dB 1.8 1.6 Min (Note 6) Typ (Note 5) -0.5 2.0 95 96 82 2.98 2.93 25 75 50 35 55 40 75 95 110 mA 75 150 dB Max (Note 6) -0.2 -0.1 Units
V
CMRR AVOL
Common Mode Rejection Ratio Large Signal Voltage Gain
VCM Stepped from 0V to 1.5V VO = 0.5V to 2.5V RL = 2k to V+/2 VO = 0.5V to 2.5V RL = 150 to V+/2
72 80 75 74 70 2.90 2.80
dB
VO
Output Swing High Output Swing Low
RL = 2k to V+/2, VID = 200mV RL = 150 to V+/2, VID = 200mV RL = 2k to V+/2, VID = -200mV RL = 150 to V /2, VID = -200mV Sourcing to V+/2 VID = 200mV (Note 10) Sinking to V+/2 VID = -200mV (Note 10)
+
V mV
ISC
Output Short Circuit Current
IOUT +PSRR IS
Output Current Positive Power Supply Rejection Ratio Supply Current (per channel)
VOUT = 0.5V from either supply V+ = 3.0V to 3.5V, VCM = 1.5V No Load
65
85 2.70 4.00 4.50
mA dB
mA
5V Electrical Characteristics
Unless otherwise specified, all limits guaranteed for at TJ = 25C, V+ = 5V, V- = 0V, VCM = VO = V+/2, and RL = 2k to V+/2. Boldface limits apply at the temperature extremes. Symbol BW BW0.1dB PBW en in THD DG Parameter -3dB BW 0.1dB Gain Flatness Full Power Bandwidth Input-Referred Voltage Noise Input-Referred Current Noise Total Harmonic Distortion Differential Gain Conditions AV = +1, VOUT = 200mVPP AV = +2, -1, VOUT = 200mVPP AV = +2, RL = 150 to V+/2, Rf = 402, VOUT = 200mVPP AV = +1, -1dB, VOUT = 2VPP f = 100kHz f = 1kHz f = 100kHz f = 1kHz f = 5MHz, VO = 2VPP, AV = +2 NTSC, AV = +2 RL =150 to V+/2 RL =1k to V+/2 DP Differential Phase NTSC, AV = +2 RL =150 to V+/2 RL =1k to V+/2 CT Rej. TS Cross-Talk Rejection Settling Time f = 5MHz, Receiver: Rf = Rg = 510, AV = +2 VO = 2VPP, 0.1%, 8pF Load Min (Note 6) 90 Typ (Note 5) 120 46 15 22 17 48 0.90 3.3 -60 0.16 0.05 0.05 0.01 47 68 dB ns deg Max (Note 6) Units
MHz MHz MHz nV/ pA/ dBc %
3
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LMH6642/6643/6644
5V Electrical Characteristics
Symbol SR VOS TC VOS IB IOS RIN CIN CMVR Parameter Slew Rate (Note 8) Input Offset Voltage Input Offset Average Drift Input Bias Current Input Offset Current Common Mode Input Resistance Common Mode Input Capacitance Input Common-Mode Voltage Range
(Continued) Unless otherwise specified, all limits guaranteed for at TJ = 25C, V+ = 5V, V- = 0V, VCM = VO = V+/2, and RL = 2k to V+/2. Boldface limits apply at the temperature extremes. Conditions AV = -1, VI = 2VPP Min (Note 6) 95 Typ (Note 5) 125 Max (Note 6) Units V/s
1
(Note 12) (Note 7)
5 7
-2.60 -3.25 800 1000
mV V/C A nA M pF
5
-1.70 20 3 2
CMRR 50dB 3.8 3.6
-0.5 4.0 95 98
-0.2 -0.1
V
CMRR AVOL
Common Mode Rejection Ratio Large Signal Voltage Gain
VCM Stepped from 0V to 3.5V VO = 0.5V to 4.50V RL = 2k to V+/2 VO = 0.5V to 4.25V RL = 150 to V+/2
72 86 82 76 72 4.90 4.65
dB
dB 82 4.98 4.90 25 100 100 150 V mV
VO
Output Swing High Output Swing Low
RL = 2k to V+/2, VID = 200mV RL = 150 to V+/2, VID = 200mV RL = 2k to V+/2, VID = -200mV RL = 150 to V /2, VID = -200mV Sourcing to V+/2 VID = 200mV (Note 10) Sinking to V+/2 VID = -200mV (Note 10)
+
ISC
Output Short Circuit Current
55 40 70 55
115 mA 140
IOUT +PSRR IS
Output Current Positive Power Supply Rejection Ratio Supply Current (per channel)
VO = 0.5V from either supply V+ = 4.0V to 6V No Load 79
70
90 2.70 4.25 5.00
mA dB
mA
5V Electrical Characteristics
Unless otherwise specified, all limits guaranteed for at TJ = 25C, V+ = 5V, V- = -5V, VCM = VO = 0V and RL = 2k to ground. Boldface limits apply at the temperature extremes. Symbol BW BW0.1dB PBW en Parameter -3dB BW 0.1dB Gain Flatness Full Power Bandwidth Input-Referred Voltage Noise Conditions AV = +1, VOUT = 200mVPP AV = +2, -1, VOUT = 200mVPP AV = +2, RL = 150 to V+/2, Rf = 806, VOUT = 200mVPP AV = +1, -1dB, VOUT = 2VPP f = 100kHz f = 1kHz Min (Note 6) 95 Typ (Note 5) 130 46 12 24 17 48 Max (Note 6) Units
MHz MHz MHz nV/
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LMH6642/6643/6644
5V Electrical Characteristics
Symbol in THD DG Parameter Input-Referred Current Noise Total Harmonic Distortion Differential Gain
(Continued) Unless otherwise specified, all limits guaranteed for at TJ = 25C, V+ = 5V, V- = -5V, VCM = VO = 0V and RL = 2k to ground. Boldface limits apply at the temperature extremes. Conditions f = 100kHz f = 1kHz f = 5MHz, VO = 2VPP, AV = +2 NTSC, AV = +2 RL =150 to V+/2 RL =1k to V /2
+
Min (Note 6)
Typ (Note 5) 0.90 3.3 -62 0.15 0.01 0.04 0.01 47 68
Max (Note 6)
Units
pA/ dBc %
DP
Differential Phase
NTSC, AV = +2 RL =150 to V+/2 RL =1k to V+/2 f = 5MHz, Receiver: Rf = Rg = 510, AV = +2 VO = 2VPP, 0.1%, 8pF Load, VS = 5V AV = -1, VI = 2VPP 100
deg
CT Rej. TS SR VOS TC VOS IB IOS RIN CIN CMVR
Cross-Talk Rejection Settling Time Slew Rate (Note 8) Input Offset Voltage Input Offset Average Drift Input Bias Current Input Offset Current Common Mode Input Resistance Common Mode Input Capacitance Input Common-Mode Voltage Range
dB ns V/s
135
1
(Note 12) (Note 7)
5 7
-2.60 -3.25 800 1000
mV V/C A nA M pF
5
-1.60 20 3 2
CMRR 50dB 3.8 3.6
-5.5 4.0 95 96
-5.2 -5.1
V
CMRR AVOL
Common Mode Rejection Ratio Large Signal Voltage Gain
VCM Stepped from -5V to 3.5V VO = -4.5V to 4.5V, RL = 2k VO = -4.0V to 4.0V, RL = 150
74 88 84 78 74 4.90 4.65
dB
dB 82 4.96 4.80 -4.96 -4.80 -4.90 -4.65 V V
VO
Output Swing High Output Swing Low
RL = 2k, VID = 200mV RL = 150, VID = 200mV RL = 2k, VID = -200mV RL = 150, VID = -200mV Sourcing to Ground VID = 200mV (Note 10) Sinking to Ground VID = -200mV (Note 10)
ISC
Output Short Circuit Current
60 35 85 65
115 mA 145 mA 90 2.70 4.50 5.50 dB
IOUT PSRR IS
Output Current Power Supply Rejection Ratio Supply Current (per channel)
VO = 0.5V from either supply (V , V ) = (4.5V, -4.5V) to (5.5V, -5.5V) No Load
+ -
75
78
mA
5
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LMH6642/6643/6644
5V Electrical Characteristics
Note 2: Human body model, 1.5k in series with 100pF.
(Continued)
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 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 150C. Note 4: The maximum power dissipation is a function of TJ(MAX), JA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) - TA)/ JA . 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: Machine Model, 0 in series with 200pF. Note 10: Short circuit test is a momentary test. See Note 11. Note 11: Output short circuit duration is infinite for VS
< 6V at room temperature and below. For VS > 6V, allowable short circuit duration is 1.5ms.
Note 12: Offset voltage average drift determined by dividing the change in VOS at temperature extremes by the total temperature change.
Connection Diagrams
SOT23-5 (LMH6642) SOIC-8 (LMH6642) SOIC-8 and MSOP-8 (LMH6643)
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Top View
Top View Top View SOIC-14 and TSSOP-14 (LMH6644)
20018563
20018568
Top View
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LMH6642/6643/6644
Typical Performance Characteristics
otherwise specified. Closed Loop Frequency Response for Various Supplies
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless Closed Loop Gain vs. Frequency for Various Gain
20018557 20018551
Closed Loop Gain vs. Frequency for Various Gain
Closed Loop Frequency Response for Various Temperature
20018550 20018535
Closed Loop Gain vs. Frequency for Various Supplies
Closed Loop Frequency Response for Various Temperature
20018548
20018534
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LMH6642/6643/6644
Typical Performance Characteristics
otherwise specified. (Continued)
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless
Large Signal Frequency Response
Closed Loop Small Signal Frequency Response for Various Supplies
20018547
20018546
Closed Loop Frequency Response for Various Supplies
0.1dB Gain Flatness for Various Supplies
20018544 20018545
VOUT (VPP) for THD < 0.5%
VOUT (VPP) for THD < 0.5%
20018509
20018508
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LMH6642/6643/6644
Typical Performance Characteristics
otherwise specified. (Continued) VOUT (VPP) for THD < 0.5%
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless
Open Loop Gain/Phase for Various Temperature
20018510
20018532
Open Loop Gain/Phase for Various Temperature
HD2 (dBc) vs. Output Swing
20018533 20018514
HD3 (dBc) vs. Output Swing
HD2 vs. Output Swing
20018515
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LMH6642/6643/6644
Typical Performance Characteristics
otherwise specified. (Continued) HD3 vs. Output Swing
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless
THD (dBc) vs. Output Swing
20018505
20018506
Settling Time vs. Input Step Amplitude (Output Slew and Settle Time)
Input Noise vs. Frequency
20018513
20018512
VOUT from V vs. ISOURCE
+
VOUT from V vs. ISINK
-
20018518
20018519
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Typical Performance Characteristics
otherwise specified. (Continued) VOUT from V+ vs. ISOURCE
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless
VOUT from V- vs. ISINK
20018516
20018517
Swing vs. VS
Short Circuit Current (to VS/2) vs. VS
20018529
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Output Sinking Saturation Voltage vs. IOUT
Output Sourcing Saturation Voltage vs. IOUT
20018520
20018501
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LMH6642/6643/6644
Typical Performance Characteristics
otherwise specified. (Continued) Closed Loop Output Impedance vs. Frequency AV = +1
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless
PSRR vs. Frequency
20018502
20018503
CMRR vs. Frequency
Crosstalk Rejection vs. Frequency (Output to Output)
20018507
20018511
VOS vs. VOUT (Typical Unit)
VOS vs. VCM (Typical Unit)
20018530
20018527
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Typical Performance Characteristics
otherwise specified. (Continued) VOS vs. VS (for 3 Representative Units)
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless
VOS vs. VS (for 3 Representative Units)
20018522
20018523
VOS vs. VS (for 3 Representative Units)
IB vs. VS
20018524
20018525
IOS vs. VS
IS vs. VCM
20018526
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LMH6642/6643/6644
Typical Performance Characteristics
otherwise specified. (Continued) IS vs. VS
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless
Small Signal Step Response
20018553
20018521
Large Signal Step Response
Large Signal Step Response
20018541
20018539
Small Signal Step Response
Small Signal Step Response
20018556
20018536
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LMH6642/6643/6644
Typical Performance Characteristics
otherwise specified. (Continued) Small Signal Step Response
At TJ = 25C, V+ = +5, V- = -5V, RF = RL = 2k. Unless
Small Signal Step Response
20018552
20018538
Large Signal Step Response
Large Signal Step Response
20018537
20018554
Large Signal Step Response
20018560
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LMH6642/6643/6644
Application Notes
Circuit Description: The LMH664X family is based on National Semiconductor's proprietary VIP10 dielectrically isolated bipolar process. This device family architecture features the following: This device family was designed to avoid output phase reversal. With input overdrive, the output is kept near supply rail (or as closed to it as mandated by the closed loop gain setting and the input voltage). See Figure 1:
*
Complimentary bipolar devices with exceptionally high ft (8GHz) even under low supply voltage (2.7V) and low bias current. A class A-B "turn-around" stage with improved noise, offset, and reduced power dissipation compared to similar speed devices (patent pending). Common Emitter push-push output stage capable of 75mA output current (at 0.5V from the supply rails) while consuming only 2.7mA of total supply current per channel. This architecture allows output to reach within milli-volts of either supply rail. Consistent performance from any supply voltage (3V-10V) with little variation with supply voltage for the most important specifications (e.g. BW, SR, IOUT, etc.)
20018542
*
*
*
Significant power saving (40%) compared to competitive devices on the market with similar performance. Application Hints: This Op Amp family is a drop-in replacement for the AD805X family of high speed Op Amps in most applications. In addition, the LMH664X will typically save about 40% on power dissipation, due to lower supply current, when compared to competition. All AD805X family's guaranteed parameters are included in the list of LMH664X guaranteed specifications in order to ensure equal or better level of performance. However, as in most high performance parts, due to subtleties of applications, it is strongly recommended that the performance of the part to be evaluated is tested under actual operating conditions to ensure full compliance to all specifications. With 3V supplies and a common mode input voltage range that extends 0.5V below V-, the LMH664X find applications in low voltage/low power applications. Even with 3V supplies, the -3dB BW (@ AV = +1) is typically 115MHz with a tested limit of 80MHz. Production testing guarantees that process variations with not compromise speed. High frequency response is exceptionally stable confining the typical -3dB BW over the industrial temperature range to 2.5%. As can be seen from the typical performance plots, the LMH664X output current capability (75mA) is enhanced compared to AD805X. This enhancement, increases the output load range, adding to the LMH664X's versatility. Because of the LMH664X's high output current capability attention should be given to device junction temperature in order not to exceed the Absolute Maximum Rating.
*
FIGURE 1. Input and Output Shown with CMVR Exceeded However, if the input voltage range of -0.5V to 1V from V+ is exceeded by more than a diode drop, the internal ESD protection diodes will start to conduct.The current in the diodes should be kept at or below 10mA. Output overdrive recovery time is less than 100ns as can be seen from Figure 2 plot:
20018543
FIGURE 2. Overload Recovery Waveform
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LMH6642/6643/6644
Application Notes
(Continued)
Single Supply, Low Power Photodiode Amplifier: The circuit shown in Figure 3 is used to amplify the current from a photo-diode into a voltage output. In this circuit, the emphasis is on achieving high bandwidth and the transimpedance gain setting is kept relatively low. Because of its high slew rate limit and high speed, the LMH664X family lends itself well to such an application. This circuit achieves approximately 1V/mA of transimpedance gain and capable of handling up to 1mApp from the photodiode. Q1, in a common base configuration, isolates the high capacitance of the photodiode (Cd) from the Op Amp input in order to maximize speed. Input is AC coupled through C1 to ease biasing and allow single supply operation. With 5V single supply, the device input/output is shifted to near half supply using a voltage divider from VCC. Note that Q1 collector does not have any voltage swing and the Miller effect is minimized. D1, tied to Q1 base, is for temperature compensation of Q1's bias point. Q1 collector current was set to be large enough to handle the peak-to-peak photodiode excitation and not too large to shift the U1 output too far from mid-supply. No matter how low an Rf is selected, there is a need for Cf in order to stabilize the circuit. The reason for this is that the Op
Amp input capacitance and Q1 equivalent collector capacitance together (CIN) will cause additional phase shift to the signal fed back to the inverting node. Cf will function as a zero in the feedback path counter-acting the effect of the CIN and acting to stabilized the circuit. By proper selection of Cf such that the Op Amp open loop gain is equal to the inverse of the feedback factor at that frequency, the response is optimized with a theoretical 45 phase margin.
(1) where GBWP is the Gain Bandwidth Product of the Op Amp Optimized as such, the I-V converter will have a theoretical pole, fp, at:
(2) With Op Amp input capacitance of 3pF and an estimate for Q1 output capacitance of about 3pF as well, CIN = 6pF. From the typical performance plots, LMH6642/6643 family GBWP is approximately 57MHz. Therefore, with Rf = 1k, from Equation 1 and 2 above. Cf = 4.1pF, and fp = 39MHz
20018564
FIGURE 3. Single Supply Photodiode I-V Converter
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LMH6642/6643/6644
Application Notes
(Continued)
Printed Circuit Board Layout and Component Values Sections: Generally, a good high frequency layout will keep power supply and ground traces away from the inverting input and output pins. Parasitic capacitances on these nodes to ground will cause frequency response peaking and possible circuit oscillations (see Application Note OA-15 for more information). National Semiconductor suggests the following evaluation boards as a guide for high frequency layout and as an aid in device testing and characterization: Device LMH6642MF LMH6642MA LMH6643MA LMH6643MM LMH6644MA Package SOT23-5 8-Pin SOIC 8-Pin SOIC 8-Pin MSOP 14-Pin SOIC Evaluation Board PN CLC730068 CLC730027 CLC730036 CLC730123 CLC730031
For this example, optimum Cf was empirically determined to be around 5pF. This time domain response is shown in Figure 4 below showing about 9ns rise/fall times, corresponding to about 39MHz for fp. The overall supply current from the +5V supply is around 5mA with no load.
20018565
FIGURE 4. Converter Step Response (1VPP, 20 ns/DIV)
These free evaluation boards are shipped when a device sample request is placed with National Semiconductor. Another important parameter in working with high speed/high performance amplifiers, is the component values selection. Choosing external resistors that are large in value will effect the closed loop behavior of the stage because of the interaction of these resistors with parasitic capacitances. These capacitors could be inherent to the device or a by-product of the board layout and component placement. Either way, keeping the resistor values lower, will diminish this interaction to a large extent. On the other hand, choosing very low value resistors could load down nodes and will contribute to higher overall power dissipation.
Ordering Information
Package 5-Pin SOT-23 SOIC-8 Part Number LMH6642MF LMH6642MFX LMH6642MA LMH6642MAX LMH6643MA LMH6643MAX MSOP-8 SOIC-14 TSSOP-14 LMH6643MM LMH6643MMX LMH6644MA LNH6644MAX LMH6644MT LMH6644MTX LMH6644MT LMH6644MA A65A LMH6643MA LMH6642MA Package Marking A64A Transport Media 1k Units Tape and Reel 3k Units Tape and Reel Rails 2.5k Units Tape and Reel Rails 2.5k Units Tape and Reel 1k Units Tape and Reel 3.5k Units Tape and Reel Rails 2.5k Units Tape and Reel Rails 2.5k Units Tape and Reel MTC14 M14A MUA08A M08A NSC Drawing MF05A
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LMH6642/6643/6644
Physical Dimensions
inches (millimeters) unless otherwise noted
5-Pin SOT23 NS Package Number MF05A
Physical Dimensions
inches (millimeters) unless otherwise noted
8-Pin SOIC NS Package Number M08A
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LMH6642/6643/6644
Physical Dimensions
inches (millimeters) unless otherwise noted
8-Pin MSOP NS Package Number MUA08A
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LMH6642/6643/6644
Physical Dimensions
inches (millimeters) unless otherwise noted
14-Pin SOIC NS Package Number M14A
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LMH6642/6643/6644 3V, Low Power, 130MHz, 75mA Rail-to-Rail Output Amplifiers
Physical Dimensions
inches (millimeters) unless otherwise noted
14-Pin TSSOP NS Package Number MTC14
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.
National Semiconductor Corporation Americas Email: support@nsc.com National Semiconductor Europe Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Francais Tel: +33 (0) 1 41 91 8790
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.
National Semiconductor Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: ap.support@nsc.com
National Semiconductor Japan Ltd. Tel: 81-3-5639-7560 Fax: 81-3-5639-7507
www.national.com
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.

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