SHA1144 Datasheet, PDF (1/6 Pages) Analog Devices – HIGH RESOLUTION 14 BIT SAMPLE AND HOLD AMPLIFIER

ANALOG
DEVICES
FEATURES
t10V min lnput/OutputRange
50ns Aperture Delay
0.5nsApertureJitter
6 p s S e t t l i n gT i m e
t0.001%Max Gain LinearityError
Completewith Input Buffer
APPLICATIONS
Trackand Hold
PeakMeasuremenSt ystems
Data Acquisition Systems
S i m u l t a n e o uSs a m p l e - a n d - H o l d
HighResolutilo+nBit
SamplaendHoldAmplifier
GENERAL DESCRIPTION
The SHA1144 is a fast sample-holdamplifier module with ac
curacy and dynamic performanceappropriatefor applications
with fast 14-bit A/D converters.In the ^"sample" mode, it acrs
as a fast amplifier, tracking the input signal. When switched to
the ^"hold" mode, the output is held at a level corresponding
to the input signal voltage at t}le instant of switching. The
droop rate in ^"hold" is appropriate to allow accurate conver-
sion by 14-bit A/D converters having conversion times of up
to 150trrs.
DYNAMIC PERFORMANCE
The SHA1144wasdesignedto be compatiblewith fast 14-bit
A/D convertersuchasthe AnalogDevices'ADC1130and
ADC1131seriesw, hich convert14 bits in 25gsand 129s,re-
spectively.Maximum acquisitiontime of 8trrsfor the SHA1144
permits high samplingrates for 14-bit conversionsT. he
SHA1144is guaranteetdo havea maximumgainnonlinearity
of 10.0017of full scaleto insure1/2LSBaccuracyin 14-bit
systemsW. henin the ^"hold" mode,the drooprateis LpVltrrs,
sothe SHA1144will hold an input signatl o 10.003%of full
scale(20V p-p)for over60oprs.
PRINCIPLEOF OPERATION
The SHA1144consistsbasicallyof two highspeedoperational
amplifiers,a storagecapacitor,and a digitally controlled
switch.It differsfrom typical sample-and-holmd odulesin one
important respectiapplicationversatility.The usercompletes
the SHA1144feedbackcircuitexternalto the module.There-
fore, the modulemay be usedin invertingor noninvertingcon-
figurationsand caneasilybe arrangedto providecircuit gainof
morethanuniry to simplifysignalconditioningin a subsystem.
FEEDBACK CONNECTIONS
A block diagramof the SHA1144is shownin Figure1. The in-
put sectionactsasa voltage-to-currenctonverter,providingthe
currentneededto chargethe ^"hold" capacitor.The output
amplifierisolatesthe ^"hold" capacitorand provideslow out-
put impedancefor drivingthe load.Sincefeedbackis not hard-
wired in the module,both invertingand noninvertinginput
terminalsareavailablea, nd the SHAl144 canbe connectedas
a follower with unity gainor potentiometricgain,aswell as
inverteror evena differentialamplifier.Sincethe unity gain
follower modewill be the most frequentapplication,perform-
ancedatalistedin the specificationtableis basedon this oper-
atingmode.
.15V
ANALOG
GROUND
+l5v
+INPUT
-INPUT
MODE
CONTROL
DIGITAL
GROUND
Figurel. Block Diagram- SHAI144
Information furnished by Anatog Devices is believed to _{be accurate}
a n d r e l i a b l e .H o h r e v e r .n o r e s p o n s i b i l i t yi s a s s u m e db y A n a l o g D e v i c e s
f o r i t s u s e ; n o r f o r a n y i n f r i n g e m e n t so f p a t e n t s o r o t h e r r i g h t so f t h i r d
p a r t i e s w h i c h m a y r e s u l t f r o m i t s u s e . N o l i c e r t s ei _s g r a n r e d _{b y i m p l i c a -}
tion or otherwise under anv
or
riohts Analoo Devices.