LMH2180SDE Datasheet, PDF (2/18 Pages) Texas Instruments – LMH2180 75 MHz Dual Clock Buffer

LMH2180
August 29, 2011
75 MHz Dual Clock Buffer
General Description
The LMH2180 is a high speed dual clock buffer designed for
portable communications and applications requiring multiple
accurate multi-clock systems. The LMH2180 integrates two
75 MHz low noise buffers with independent shutdown pins
into a small package. The LMH2180 ensures superb system
operation between the baseband and the oscillator signal
path by eliminating crosstalk between the multiple clock sig-
nals.
Unique technology and design provides the LMH2180 with
the ability to accurately drive both large capacitive and resis-
tive loads. Low supply current combined with shutdown pins
for each channel means the LMH2180 is ideal for battery
powered applications. This part does not use an internal
ground reference, thus providing additional system flexibility.
The flexible buffers provide system designers the capacity to
manage complex clock signals in the latest wireless applica-
tions. Each buffer delivers 106 V/μs internal slew rate with
independent shutdown and duty cycle precision. Each input
is internally biased to 1V, removing the need for external re-
sistors. Both channels have rail-to-rail inputs and outputs, a
gain of one, and are AC coupled with the use of one capacitor.
Replacing a discrete buffer solution with the LMH2180 pro-
vides many benefits: simplified board layout, minimized par-
asitic components, simplified BOM, design durability across
multiple applications, simplification of clock paths, and the
ability to reduce the number of clock signal generators in the
system. The LMH2180 is produced in the tiny packages min-
imizing the required PCB space.
Features
(Typical values are: V_SUPPLY = 2.7V and C_L = 10 pF, unless
otherwise specified.)
■ ^{Small signal bandwidth}
■ ^{Supply voltage range}
■ ^{Phase noise (V}_IN ^{= 1 V}_PP^,
f_C = 38.4 MHz, Δf = 1 kHz)
■ ^{Slew rate}
■ ^{Total supply current}
■ ^{Shutdown current}
■ ^{Rail-to-rail input and output}
■ ^{Individual buffer enable pins}
■ ^{Rapid T}_on ^technology
■ ^{Crosstalk rejection circuitry}
78 MHz
2.4V to 5V
−123 dBc/Hz
106 V/μs
2.3 mA
30 µA
■ ^Packages:
— 8-Pin LLP, Solder Bump and no Pullback
— 8-Bump micro SMD
■ ^{Temperature range}
−40°C to 85°C
Applications
■ ^{3G mobile applications}
■ ^{WLAN–WiMAX modules}
■ ^{TD_SCDMA multi-mode MP3 and camera}
■ ^{GSM modules}
■ ^{Oscillator modules}
Typical Application
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