LMH6644-MIL Datasheet, PDF (21/28 Pages) Texas Instruments – Low-Power, 130-MHz, 75-mA Rail-to-Rail Output Amplifier

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8 Detailed Description
LMH6644-MIL
SNOSD65 – JUNE 2017
8.1 Overview
The LMH6644-MIL is based on proprietary VIP10 dielectrically isolated bipolar process. This device architecture
features the following:
• Complimentary bipolar devices with exceptionally high f_t (∼8 GHz) even under low-supply voltage (2.7 V) 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 75-mA output current (at 0.5 V from the supply rails)
while consuming only 2.7 mA of total supply current per channel. This architecture allows output to reach
within mV of either supply rail.
• Consistent performance over the entire operating supply voltage range with little variation for the most
important specifications (for example, BW, SR, I_OUT, and so forth)
• Significant power saving (∼40%) compared to competitive devices on the market with similar performance.
8.2 Functional Block Diagram
V+
R
IN+
V+
V+
R
IN-
V-
V-
Figure 54. Input Equivalent Circuit
8.3 Feature Description
The LMH6644-MIL is a drop-in replacement for the AD805X family of high-speed op amps in most applications.
In addition, the LMH6644-MIL will typically save about 40% on power dissipation, due to lower supply current,
when compared to competition. All AD805X family’s specified parameters are included in the list of LMH6644-
MIL ensured specifications in order to ensure equal or better level of performance. However, as in most high-
performance parts and 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.
8.4 Device Functional Modes
With 3-V supplies and a common-mode input voltage range that extends 0.5 V below V^–, the LMH6644-MIL find
applications in low voltage/low power applications. Even with 3-V supplies, the –3dB BW (@ A_V = +1) is typically
115 MHz with a tested limit of 80 MHz. Production testing guarantees that process variations will not compromise
speed. High-frequency response is exceptionally stable, confining the typical –3dB BW over the industrial
temperature range to ±2.5%.
As seen in Typical Performance Characteristics, the LMH6644-MIL output current capability (∼75 mA) is
enhanced compared to AD805X. This enhancement increases the output load range, adding to the LMH6644-
MIL’s versatility. Since LMH6644-MIL is capable of high-output current, device junction temperature should not to
exceed the Absolute Maximum Ratings.
Copyright © 2017, Texas Instruments Incorporated
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