LTC2393IUK-16PBF [Linear]
16-Bit, 1Msps SAR ADC With 94db SNR; 16位, 1Msps的SAR型ADC的SNR 94分贝型号: | LTC2393IUK-16PBF |
厂家: | Linear |
描述: | 16-Bit, 1Msps SAR ADC With 94db SNR |
文件: | 总24页 (文件大小:213K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LTC2393-16
16-Bit, 1Msps SAR ADC
With 94dB SNR
FEATURES
DESCRIPTION
The LTC®2393-16 is a low noise, high speed 16-bit suc-
cessive approximation register (SAR) ADC. Operating
from a single 5V supply, the LTC2393-16 supports a large
±±.ꢀ96V fully differential input range, maꢁing it ideal for
high performance applications which require maximum
dynamicrange.TheLTC2393-16achieves±2LSꢂꢃILmax,
no missing codes at 16-bits and 9±.2dꢂ SIR (typ).
n
1Msps Throughput Rate
n
±±2LS ꢀI2 ꢁMaꢂx
n
Guaranteed 16-Sit Io Missing Codes
n
94.±dS LIR ꢁTypx at f = ±0kHz
ꢀI
n
Guaranteed Operation to 125/C
n
Single 5V Supply
n
1.8V to 5V ꢃꢄO Voltages
n
1±ꢀmW Power Dissipation
The LTC2393-16 includes a precision internal reference
with a guaranteed ꢀ.5% initial accuracy and a ±2ꢀppmꢄ/C
(max)temperaturecoefficient.Fast1Mspsthroughputwith
nocyclelatencyinbothparallelandserialinterfacemodes
maꢁes the LTC2393-16 ideally suited for a wide variety
of high speed applications. An internal oscillator sets the
conversion time, easing external timing considerations.
The LTC2393-16 dissipates only 1±ꢀmW at 1Msps, while
both nap and sleep power-down modes are provided to
further reduce power during inactive periods.
n
±±.ꢀ96V Differential ꢃnput Range
n
ꢃnternal Reference (2ꢀppmꢄ/C Max)
n
Io Pipeline Delay, Io Cycle Latency
n
Parallel and Serial ꢃnterface
ꢃnternal Conversion Clocꢁ
n
n
±8-pin 7mm × 7mm LQFP and QFI Pacꢁages
APPLICATIONS
n
Medical ꢃmaging
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarꢁs of Linear
Technology Corporation. All other trademarꢁs are the property of their respective owners.
n
High Speed Data Acquisition
n
Digital Signal Processing
ꢃndustrial Process Control
ꢃnstrumentation
ATE
n
n
n
TYPICAL APPLICATION
16k Point FFT fL = 1Msps,
5V
5V
ꢀ.1μF
1.8V TO 5V
±.7μF
fꢀI = ±0kHz
1ꢀμF
ꢀ.1μF
1ꢀμF
ꢀ
–2ꢀ
SIR = 9±.2dꢂ
THD ꢀ –1ꢀ5dꢂ
SꢃIAD = 93.9dꢂ
SFDR = 1ꢀ8dꢂ
AIALOG ꢃIPUT
ꢀV TO ±.ꢀ96V
AVP
DVP
OVP
PARALLEL
OR
SERꢃAL
ꢃITERFACE
–±ꢀ
2±9Ω
16 ꢂꢃT
+
ꢃI
–6ꢀ
–8ꢀ
LT635ꢀ
22ꢀꢀpF
2±9Ω
LTC2393-16
SERꢄPAR
ꢂYTESWAP
Oꢂꢄ2C
CS
–1ꢀꢀ
–12ꢀ
–1±ꢀ
–16ꢀ
–
ꢃI
RD
SꢃIGLE-EIDED-
TO-DꢃFFEREITꢃAL
DRꢃVER
ꢂUSY
VCM REFꢃI REFOUT CNVST PD RESET GID OGID
1ꢀμF 1μF
239316 TAꢀ1
SAMPLE CLOCK
–18ꢀ
ꢀ
±ꢀꢀ
5ꢀꢀ
1ꢀꢀ
2ꢀꢀ
3ꢀꢀ
FREQUEICY (ꢁHz)
239316 Gꢀ8
239316f
1
LTC2393-16
ABSOLUTE MAXIMUM RATINGS ꢁIotes 1, ±x
Supply Voltage (V , V , V ) ..........................6.ꢀV
Operating Temperature Range
AVP DVP OVP
Analog ꢃnput Voltage (Iote 3)
LTC2393C ................................................ ꢀ/C to 7ꢀ/C
LTC2393ꢃ.............................................. –±ꢀ/C to 85/C
LTC2393H .......................................... –±ꢀ/C to 125/C
Storage Temperature Range................... –65/C to 15ꢀ/C
+
–
ꢃI , ꢃI , REFꢃI, CNVST .. (GID – ꢀ.3V) to (V
+ ꢀ.3V)
+ ꢀ.3V)
+ ꢀ.3V)
AVP
OVP
OVP
Digital ꢃnput Voltage........(GID – ꢀ.3V) to (V
Digital Output Voltage .....(GID – ꢀ.3V) to (V
Power Dissipation...............................................5ꢀꢀmW
PIN CONFIGURATION
TOP VꢃEW
TOP VꢃEW
GID 1
AVP 2
DVP 3
36 VCM
35 GID
3± CNVST
33 PD
32 RESET
31 CS
GID
AVP
1
2
3
±
5
6
7
8
9
36 VCM
35 GID
3± CNVST
33 PD
32 RESET
31 CS
3ꢀ RD
29 ꢂUSY
28 D15
27 D1±
26 D13
25 D12
DVP
SERꢄPAR ±
GID 5
Oꢂꢄ2C 6
GID 7
ꢂYTESWAP 8
Dꢀ 9
SERꢄPAR
GID
Oꢂꢄ2C
GID
ꢂYTESWAP
Dꢀ
±9
GID
3ꢀ RD
29 ꢂUSY
28 D15
27 D1±
26 D13
25 D12
D1 1ꢀ
D2 11
D3 12
D1 1ꢀ
D2 11
D3 12
UK PACKAGE
±8-LEAD (7mm s 7mm) PLASTꢃC QFI
LX PACKAGE
T
= 125/C, θ = 29/CꢄW
JA
±8-LEAD (7mm s 7mm) PLASTꢃC LQFP
JMAX
EXPOSED PAD (PꢃI ±9) ꢃS GID, MUST ꢂE SOLDERED TO PCꢂ
T
= 125/C, θ = 55/CꢄW
JA
JMAX
ORDER INFORMATION
2EAD FREE FꢀIꢀLH
LTC2393CUK-16#PꢂF
LTC2393ꢃUK-16#PꢂF
2EAD FREE FꢀIꢀLH
LTC2393CLX-16#PꢂF
LTC2393ꢃLX-16#PꢂF
LTC2393HLX-16#PꢂF
TAPE AID REE2
PART MARKꢀIG*
PACKAGE DELCRꢀPTꢀOI
TEMPERATURE RAIGE
ꢀ/C to 7ꢀ/C
LTC2393CUK-16#TRPꢂF LTC2393UK-16
±8-Lead 7mm × 7mm Plastic QFI
±8-Lead 7mm × 7mm Plastic QFI
PACKAGE DELCRꢀPTꢀOI
LTC2393ꢃUK-16#TRPꢂF
TRAY
LTC2393UK-16
PART MARKꢀIG*
LTC2393LX-16
LTC2393LX-16
LTC2393LX-16
–±ꢀ/C to 85/C
TEMPERATURE RAIGE
ꢀ/C to 7ꢀ/C
LTC2393CLX-16#PꢂF
LTC2393ꢃLX-16#PꢂF
LTC2393HLX-16#PꢂF
±8-Lead 7mm × 7mm Plastic LQFP
±8-Lead 7mm × 7mm Plastic LQFP
±8-Lead 7mm × 7mm Plastic LQFP
–±ꢀ/C to 85/C
–±ꢀ/C to 125/C
Consult LTC Marꢁeting for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marꢁeting for information on non-standard lead based finish parts.
For more information on lead free part marꢁing, go to: http:ꢄꢄwww.linear.comꢄleadfreeꢄ
For more information on tape and reel specifications, go to: http:ꢄꢄwww.linear.comꢄtapeandreelꢄ
239316f
2
LTC2393-16
ANALOG INPUT The l denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at TA = ±5°C. ꢁIote 4x
LYMSO2
PARAMETER
COIDꢀTꢀOIL
MꢀI
TYP
MAX
AVP
AVP
UIꢀTL
+
+
l
l
l
l
l
V
V
V
V
Absolute ꢃnput Range (ꢃI )
(Iote 5)
–ꢀ.ꢀ5
–ꢀ.ꢀ5
V
V
ꢃI
ꢃI
ꢃI
–
+
–
Absolute ꢃnput Range (ꢃI )
(Iote 5)
–
+
–
– V
ꢃnput Differential Voltage Range
Common Mode ꢃnput Range
Analog ꢃnput Leaꢁage Current
Analog ꢃnput Capacitance
V
ꢃI
= V – V
–V
V
REF
V
ꢃI
ꢃI
ꢃI
REF
V
ꢄ2 – ꢀ.ꢀ5
V
ꢄ2
REF
V
ꢄ2 + ꢀ.ꢀ5
±1
V
CM
REF
REF
ꢃ
μA
ꢃI
C
Sample Mode
Hold Mode
±5
5
pF
pF
ꢃI
CMRR
ꢃnput Common Mode Rejection Ratio
7ꢀ
dꢂ
CONVERTER CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = ±5°C. ꢁIote 4x
LYMSO2
PARAMETER
COIDꢀTꢀOIL
MꢀI
16
TYP
MAX
UIꢀTL
ꢂits
l
l
Resolution
Io Missing Codes
Transition Ioise
16
ꢂits
ꢀ.3
±1
LSꢂ
RMS
l
l
l
ꢃIL
ꢃntegral Linearity Error
Differential Linearity Error
ꢂipolar Zero Error
ꢂipolar Zero Error Drift
ꢂipolar Full-Scale Error
(Iote 6)
(Iote 7)
–2
–1
–7
2
1
7
LSꢂ
DIL
ꢂZE
LSꢂ
LSꢂ
1
ppmꢄ/C
l
FSE
External Reference
ꢃnternal Reference (Iote 7)
ꢀ.1
ꢀ.1
%
%
ꢂipolar Full-Scale Error Drift
±1ꢀ
ppmꢄ/C
DYNAMIC ACCURACY The l denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at TA = ±5°C. AꢀI = –1dSFL ꢁIotes 4, 8x
LYMSO2
SꢃIAD
SIR
PARAMETER
COIDꢀTꢀOIL
MꢀI
92
TYP
93.9
9±.2
MAX
UIꢀTL
dꢂ
l
l
l
Signal-to-(Ioise + Distortion) Ratio
Signal-to-Ioise Ratio
f
ꢃI
f
ꢃI
= 2ꢀꢁHz
= 2ꢀꢁHz
92.5
dꢂ
THD
Total Harmonic Distortion
f
ꢃI
f
ꢃI
= 2ꢀꢁHz, First 5 Harmonics (C- and ꢃ-Grades)
= 2ꢀꢁHz, First 5 Harmonics (H-Grade)
–1ꢀ5
–1ꢀ5
–1ꢀꢀ
–98
dꢂ
dꢂ
SFDR
Spurious-Free Dynamic Range
–3dꢂ ꢃnput ꢂandwidth
Aperture Delay
f
ꢃI
= 2ꢀꢁHz
1ꢀ±
5ꢀ
ꢀ.5
7
dꢂ
MHz
ns
Aperture Jitter
ps
RMS
Transient Response
Full-Scale Step
6ꢀ
ns
239316f
3
LTC2393-16
INTERNAL REFERENCE CHARACTERISTICS The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = ±5°C. ꢁIote 4x
PARAMETER
COIDꢀTꢀOIL
MꢀI
TYP
±.ꢀ96
±1ꢀ
2.6
MAX
±.116
±2ꢀ
UIꢀTL
V
V
REF
V
REF
V
REF
Output Voltage
Output Tempco
Output ꢃmpedance
ꢃ
ꢃ
= ꢀ
±.ꢀ76
OUT
OUT
l
= ꢀ (ꢃ- and H-Grades) (Iote 11)
ppmꢄ/C
ꢁΩ
–ꢀ.1mA ≤ ꢃ
≤ ꢀ.1mA
OUT
External Reference Voltage
REFꢃI ꢃnput ꢃmpedance
2.5
±.ꢀ96
85
AVP – ꢀ.5
V
ꢁΩ
V
Line Regulation
AVP = ±.75V to 5.25V
= ꢀ
ꢀ.3
mVꢄV
V
REF
VCM Output Voltage
ꢃ
2.ꢀ8
OUT
DIGITAL INPUTS AND DIGITAL OUTPUTS The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = ±5°C. ꢁIote 4x
LYMSO2
PARAMETER
COIDꢀTꢀOIL
MꢀI
TYP
MAX
UIꢀTL
V
l
l
l
V
ꢃH
V
ꢃL
High Level ꢃnput Voltage
Low Level ꢃnput Voltage
Digital ꢃnput Current
ꢀ.8 • OVP
ꢀ.5
1ꢀ
V
ꢃ
V
= ꢀV to OVP
ꢃI
–1ꢀ
OVP – ꢀ.2
–1ꢀ
μA
pF
ꢃI
C
V
V
Digital ꢃnput Capacitance
High Level Output Voltage
Low Level Output Voltage
Hi-Z Output Leaꢁage Current
Output Source Current
Output Sinꢁ Current
5
ꢃI
l
l
l
ꢃ = –5ꢀꢀμA
O
V
OH
OL
ꢃ = 5ꢀꢀμA
O
ꢀ.2
1ꢀ
V
ꢃ
ꢃ
ꢃ
V
OUT
V
OUT
V
OUT
= ꢀV to OVP
= ꢀV
μA
mA
mA
OZ
–1ꢀ
1ꢀ
SOURCE
SꢃIK
= OVP
POWER REQUIREMENTS The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = ±5°C. ꢁIote 4x
LYMSO2
, V
PARAMETER
Supply Voltage
Supply Voltage
COIDꢀTꢀOIL
MꢀI
±.75
1.71
TYP
MAX
5.25
5.25
UIꢀTL
l
V
5
V
V
AVP DVP
V
OVP
l
l
ꢃ
DD
Supply Current
Power Down Mode
1Msps Sample Rate with Iap Mode
Conversion Done and All Digital ꢃnputs Tied to OVP
28
35
35
25ꢀ
mA
μA
P
Power Dissipation
Power Down Mode
1Msps Sample Rate with Iap Mode
Conversion Done and All Digital ꢃnputs Tied to OVP
1±ꢀ
175
175
125ꢀ
mW
μW
D
239316f
4
LTC2393-16
TIMING CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = ±5°C. ꢁIote 4x
LYMSO2
PARAMETER
COIDꢀTꢀOIL
MꢀI
TYP
MAX
1
UIꢀTL
Msps
ns
l
l
l
l
l
l
l
l
l
l
f
t
t
t
t
t
t
t
t
t
Sampling Frequency
Conversion Time
SMPL
6ꢀꢀ
385
COIV
Acquisition Time
ns
ACQ
±
CNVST Low Time
2ꢀ
ns
CNVST High Time
25ꢀ
ns
5
C = 15pF
L
15
ns
CNVST↓ to ꢂUSY Delay
RESET Pulse Width
SCLK Period
6
5
12.5
±
ns
7
(Iote 9)
ns
8
SCLK High Time
ns
9
SCLK Low Time
±
ns
1ꢀ
t , t
SCLK Rise and Fall Times
SDꢃI Setup Time
(Iote 1ꢀ)
1
μs
r
f
l
l
l
l
l
l
l
l
t
11
t
12
t
13
t
1±
t
15
t
16
t
17
t
18
2
1
2
ns
SDꢃI Hold Time
ns
C = 15pF
L
8
8
ns
SDOUT Delay After SCLK↑
SDOUT Delay After CS↓
CS↓ to SCLK Setup Time
Data Valid to ꢂUSY↓
Data Access Time after RD↓ or ꢂYTESWAP↑
ꢂus Relinquish Time
ns
2ꢀ
1
ns
ns
1ꢀ
ns
1ꢀ
ns
Iote 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Iote 7: ꢂipolar zero error is the offset voltage measured from –ꢀ.5LSꢂ
when the output code flicꢁers between ꢀꢀꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ and 1111
1111 1111 1111. ꢂipolar full-scale error is the worst-case of –FS or +FS
untrimmed deviation from ideal first and last code transitions and includes
the effect of offset error.
Iote ±: All voltage values are with respect to ground.
Iote 8: All specifications in dꢂ are referred to a full-scale ±±.ꢀ96V input
with a ±.ꢀ96V reference voltage.
Iote 3: When these pin voltages are taꢁen below ground or above
AVP, DVP or OVP, they will be clamped by internal diodes. This product can
handle input currents up to 1ꢀꢀmA below ground or above AVP, DVP or
OVP without latchup.
Iote 9: t of 8ns maximum allows a shift clocꢁ frequency up to
13
2 • (t + t
) for falling edge capture with 5ꢀ% duty cycle and up to
SETUP
13
8ꢀMHz for rising capture. t
is the set-up time of the receiving logic.
SETUP
Iote 4: AVP = DVP = OVP = 5V, f
= 1MHz, external reference equal to
SMPL
±.ꢀ96V unless otherwise noted.
Iote 10: Guaranteed by design.
Iote 5: Recommended operating conditions.
Iote 11: Temperature coefficient is calculated by dividing the maximum
change in output voltage by the specified temperature range.
Iote 6: ꢃntegral nonlinearity is defined as the deviation of a code from a
straight line passing through the actual endpoints of the transfer curve.
The deviation is measured from the center of the quantization band.
±V
t
WꢃDTH
ꢀ.5V
5ꢀ%
5ꢀ%
t
t
DELAY
DELAY
239316Fꢀ1
±V
±V
ꢀ.5V
ꢀ.5V
Figure 1. Voltage 2evels for Timing Lpecifications
239316f
5
LTC2393-16
TYPICAL PERFORMANCE CHARACTERISTICS TA = ±5°C, fLMP2 = 1Msps, unless otherwise noted.
ꢀntegral Ionlinearity
vs Output Code
Differential Ionlinearity
vs Output Code
DC Histogram
ꢁEꢂternal Referencex
1.5
1.ꢀ
2ꢀꢀꢀꢀꢀꢀ
18ꢀꢀꢀꢀꢀ
16ꢀꢀꢀꢀꢀ
1±ꢀꢀꢀꢀꢀ
12ꢀꢀꢀꢀꢀ
1ꢀꢀꢀꢀꢀꢀ
8ꢀꢀꢀꢀꢀ
6ꢀꢀꢀꢀꢀ
±ꢀꢀꢀꢀꢀ
2ꢀꢀꢀꢀꢀ
ꢀ
2.ꢀ
1.5
1.ꢀ
ꢀ.5
ꢀ
ꢀ.5
ꢀ
–ꢀ.5
–1.ꢀ
–1.5
–2.ꢀ
–ꢀ.5
–1.ꢀ
–1.5
3276±
32766 32768 3277ꢀ 32772
CODE
ꢀ
1638±
32768
±9152
65536
32768
ꢀ
1638±
±9152
65536
OUTPUT CODE
OUTPUT CODE
239316 Gꢀ2
239316 Gꢀ3
239316 Gꢀ1
DC Histogram
ꢁꢀnternal Referencex
ꢀnternal Reference Output
vs Temperature
Offset Error vs Temperature
2ꢀꢀꢀꢀꢀꢀ
18ꢀꢀꢀꢀꢀ
16ꢀꢀꢀꢀꢀ
1±ꢀꢀꢀꢀꢀ
12ꢀꢀꢀꢀꢀ
1ꢀꢀꢀꢀꢀꢀ
8ꢀꢀꢀꢀꢀ
6ꢀꢀꢀꢀꢀ
±ꢀꢀꢀꢀꢀ
2ꢀꢀꢀꢀꢀ
ꢀ
±.ꢀ975
±.ꢀ97ꢀ
±.ꢀ965
±.ꢀ96ꢀ
±.ꢀ955
±.ꢀ95ꢀ
±.ꢀ9±5
±.ꢀ9±ꢀ
±.ꢀ935
±.ꢀ93ꢀ
±.ꢀ925
1.ꢀ
ꢀ.8
TC = ±ppmꢄ/C
ꢀ.6
ꢀ.±
ꢀ.2
ꢀ
3276± 32766 32768 3277ꢀ 32772
–55 –35 –15
5
25 ±5 65 85 1ꢀ5 125
–55 –35 –15
5
25 ±5 65 85 1ꢀ5 125
TEMPERATURE (/C)
CODE
TEMPERATURE (/C)
239316 Gꢀ±
239316 Gꢀ6
239316 Gꢀ5
16k Point FFT fL = 1Msps,
fꢀI = ±0kHz
16k Point FFT fL = 1Msps,
fꢀI = 100kHz
Full-Lcale Error vs Temperature
1ꢀ
8
ꢀ
–2ꢀ
ꢀ
–2ꢀ
SIR = 9±.2dꢂ
SIR = 9±.2dꢂ
THD ꢀ –1ꢀꢀ.6dꢂ
SꢃIAD = 93.3dꢂ
SFDR = 1ꢀ5.2dꢂ
THD ꢀ –1ꢀ5dꢂ
SꢃIAD = 93.9dꢂ
SFDR = 1ꢀ8dꢂ
6
–±ꢀ
–±ꢀ
±
–6ꢀ
–6ꢀ
2
–8ꢀ
–8ꢀ
ꢀ
–1ꢀꢀ
–12ꢀ
–1±ꢀ
–16ꢀ
–18ꢀ
–1ꢀꢀ
–12ꢀ
–1±ꢀ
–16ꢀ
–2
–±
–6
–8
–1ꢀ
–18ꢀ
–55 –35 –15
5
25 ±5 65 85 1ꢀ5 125
ꢀ
±ꢀꢀ
5ꢀꢀ
ꢀ
±ꢀꢀ
5ꢀꢀ
1ꢀꢀ
2ꢀꢀ
3ꢀꢀ
1ꢀꢀ
2ꢀꢀ
3ꢀꢀ
TEMPERATURE (/C)
FREQUEICY (ꢁHz)
FREQUEICY (ꢁHz)
239316 Gꢀ7
239316 Gꢀ9
239316 Gꢀ8
239316f
6
LTC2393-16
TYPICAL PERFORMANCE CHARACTERISTICS TA = ±5°C, fLMP2 = 1Msps, unless otherwise noted.
THD, Harmonics
LIR, LꢀIAD at fꢀI = ±0kHz
vs Temperature
LIR, LꢀIAD vs ꢀnput Frequency
vs ꢀnput Frequency
96
9±
92
9ꢀ
88
86
8±
82
8ꢀ
–7ꢀ
–75
95.ꢀ
9±.5
9±.ꢀ
93.5
93.ꢀ
SIR
–8ꢀ
SꢃIAD
SIR
–85
–9ꢀ
SꢃIAD
–95
THD
3RD
2ID
–1ꢀꢀ
–1ꢀ5
–11ꢀ
–115
–12ꢀ
1ꢀꢀ 125
1ꢀꢀ 125
15ꢀ 175
ꢀ
25 5ꢀ 75
15ꢀ 175 2ꢀꢀ
ꢀ
25
2ꢀꢀ
5ꢀ 75
–55 –35 –15
5
25 ±5 65 85 1ꢀ5 125
FREQUEICY (ꢁHz)
FREQUEICY (ꢁHz)
TEMPERATURE (/C)
239316 G1ꢀ
239316 G11
239316 G12
THD, Harmonics at fꢀI = ±0kHz
vs Temperature
Lupply Current vs Lampling
Frequency
LIR, LꢀIAD vs ꢀnput 2evel
3ꢀ
95.ꢀ
9±.5
9±.ꢀ
93.5
93.ꢀ
–9ꢀ
–95
SIR
25
2ꢀ
SꢃIAD
–1ꢀꢀ
THD
3RD
–1ꢀ5
–11ꢀ
15
1ꢀ
2ID
–115
–12ꢀ
5
ꢀ
ꢀ.1
1
1ꢀ
1ꢀꢀ
1ꢀꢀꢀ
–2ꢀ
–1ꢀ
–±ꢀ
ꢀ
–3ꢀ
–55 –35 –15
5
25 ±5 65 85 1ꢀ5 125
SAMPLꢃIG FREQUEICY (ꢁHz)
TEMPERATURE (/C)
ꢃIPUT LEVEL (dꢂ)
239316 G15
239316 G1±
239316 G13
Power-Down Current
vs Temperature
Lupply Current vs Temperature
3ꢀ
25
9ꢀ
8ꢀ
7ꢀ
6ꢀ
5ꢀ
±ꢀ
3ꢀ
2ꢀ
1ꢀ
ꢀ
AVP
2ꢀ
15
1ꢀ
DVP
DVP
OVP
5
ꢀ
AVP
OVP
–55 –35 –15
5
25 ±5 65 85 1ꢀ5 125
–55 –35 –15
5
25 ±5 65 85 1ꢀ5 125
TEMPERATURE (/C)
TEMPERATURE (/C)
239316 G16
239316 G17
239316f
7
LTC2393-16
PIN FUNCTIONS
GID ꢁPins 1, 5, 7, ±0, 35, 41, 44, 48, Eꢂposed Pad
Pin 49 ꢁQFI Onlyxx: Ground. All GID pins must be con-
nected to a solid ground plane. Exposed pad must be
soldered directly to the ground plane.
D6 ꢁPin 15x: Data ꢂit 6. When SERꢄPAR = ꢀ this pin is
ꢂit 6 of the parallel port data output bus.
D7 ꢁPin 16x: Data ꢂit 7. When SERꢄPAR = ꢀ this pin is
ꢂit 7 of the parallel port data output bus.
AVP ꢁPins ±, 40, 45, 46, 47x: 5V Analog Power Supply.
The range of AVP is ±.75V to 5.25V. ꢂypass AVP to GID
with a good quality ꢀ.1μF and a 1ꢀμF ceramic capacitor
in parallel.
OGID ꢁPin 17x: Digital Ground for the ꢃnputꢄOutput
ꢃnterface.
OVP ꢁPin 18x: Digital Power Supply for the ꢃnputꢄOutput
ꢃnterface. The range for OVP is 1.8V to 5V. ꢂypass OVP
to OGID with a good quality ±.7μF ceramic capacitor
close to the pin.
DVP ꢁPins 3, 19x: 5V Digital Power Supply. The range of
DVP is ±.75V to 5.25V. ꢂypass DVP to GID with a good
quality ꢀ.1μF and a 1ꢀμF ceramic capacitor in parallel.
D8 ꢁPin ±1x: Data ꢂit 8. When SERꢄPAR = ꢀ this pin is
ꢂit 8 of the parallel port data output bus.
LER/PAR ꢁPin 4x: SerialꢄParallel Selection ꢃnput. This pin
controls the digital interface. A logic high on this pin se-
lects the serial interface and a logic low selects the parallel
interface. ꢃn the serial mode the non-active digital outputs
are high impedance.
D9/LDꢀI ꢁPin ±±x: Data ꢂit 9ꢄSerial Data ꢃnput. When
SERꢄPAR = ꢀ this pin is ꢂit 9 of the parallel port data
output bus. When SERꢄPAR = 1, (serial mode) this is
the serial data input. SDꢃI can be used as a data input to
daisy-chain two or more conversion results into a single
SDOUT line. The digital data level on SDꢃI is output on
SDOUT with a delay of 16 SCLK periods after the start of
the read sequence.
OS/2C ꢁPin 6x: Offset ꢂinaryꢄTwo’s Complement ꢃnput.
When Oꢂꢄ2C is high, the digital output is offset binary.
When low, the MSꢂ is inverted resulting in two’s comple-
ment output.
SYTELWAP ꢁPin 8x: ꢂYTESWAP ꢃnput. With ꢂYTESWAP
low, data will be output with Pin 28 (D15) being the
MSꢂ and Pin 9 (Dꢀ) being the LSꢂ. With ꢂYTESWAP
high, the upper eight bits and the lower eight bits will
be switched. The MSꢂ is output on Pin 16 and ꢂit 8 is
output on Pin 9. ꢂit 7 is output on Pin 28 and the LSꢂ is
output on Pin 21.
D10/LDOUTꢁPin±3x:Dataꢂit1ꢀꢄSerialDataOuput.When
SERꢄPAR = ꢀ this pin is ꢂit 1ꢀ of the parallel port data
output bus. When SERꢄPAR = 1, (serial mode) this is the
serial data output. The conversion result can be clocꢁed
out serially on this pin synchronized to SCLK. The data
is clocꢁed out MSꢂ first on the rising edge of SCLK and
is valid on the falling edge of SCLK. The data format is
determined by the logic level of Oꢂꢄ2C.
D0 ꢁPin 9x: Data ꢂit ꢀ. When SERꢄPAR = ꢀ this pin is ꢂit ꢀ
of the parallel port data output bus.
D11/LC2K ꢁPin ±4x: Data ꢂit 11ꢄSerial Clocꢁ ꢃnput. When
SERꢄPAR = ꢀ this pin is ꢂit 11 of the parallel port data
output bus. When SERꢄPAR = 1, (serial mode) this is the
serial clocꢁ input.
D1 ꢁPin 10x: Data ꢂit 1. When SERꢄPAR = ꢀ this pin is
ꢂit 1 of the parallel port data output bus.
D± ꢁPin 11x: Data ꢂit 2. When SERꢄPAR = ꢀ this pin is
ꢂit 2 of the parallel port data output bus.
D1± ꢁPin ±5x: Data ꢂit 12. When SERꢄPAR = ꢀ this pin is
ꢂit 12 of the parallel port data output bus.
D3 ꢁPin 1±x: Data ꢂit 3. When SERꢄPAR = ꢀ this pin is
ꢂit 3 of the parallel port data output bus.
D13 ꢁPin ±6x: Data ꢂit 13. When SERꢄPAR = ꢀ this pin is
ꢂit 13 of the parallel port data output bus.
D4 ꢁPin 13x: Data ꢂit ±. When SERꢄPAR = ꢀ this pin is
ꢂit ± of the parallel port data output bus.
D14 ꢁPin ±7x: Data ꢂit 1±. When SERꢄPAR = ꢀ this pin is
ꢂit 1± of the parallel port data output bus.
D5 ꢁPin 14x: Data ꢂit 5. When SERꢄPAR = ꢀ this pin is
ꢂit 5 of the parallel port data output bus.
239316f
8
LTC2393-16
PIN FUNCTIONS
D15 ꢁPin ±8x: Data ꢂit 15. When SERꢄPAR = ꢀ this pin is
ꢂit 15 of the parallel port data output bus. The data format
is determined by the logic level of Oꢂꢄ2C.
VCM ꢁPin 36x: Common Mode Analog Output. Typically
the output voltage is 2.ꢀ±8V. ꢂypass to GID with a 1ꢀμF
capacitor.
SULY ꢁPin ±9x: ꢂusy Output. A low-to-high transition oc-
curs when a conversion is started. ꢃt stays high until the
conversion is complete. The falling edge of ꢂUSY can be
used as the data-ready clocꢁ signal.
REFOUT ꢁPin 37x: ꢃnternal Reference Output. Iominal
output voltage is ±.ꢀ96V. Connect this pin to REFꢃI if us-
ing the internal reference. ꢃf an external reference is used
connect REFOUT to ground.
RD ꢁPin 30x: Read Data ꢃnput. When CS and RD are both
REFꢀI ꢁPin 38x: Reference ꢃnput. An external reference
can be applied to REFꢃI if a more accurate reference is
required. ꢃf an external reference is used tie REFOUT to
ground.
low, the parallel and serial output bus is enabled.
CS ꢁPin 31x: Chip Select. When CS and RD are both low,
the parallel and serial output bus is enabled. CS is also
used to gate the external shift clocꢁ.
REFLEILE ꢁPin 39x: Reference ꢃnput Sense. Leave
REFSEISE open when using the internal reference. ꢃf
an external reference is used connect REFSEISE to the
ground pin of the external reference.
RELET ꢁPin 3±x: Reset ꢃnput. When high the LTC2393-16
isreset, andifthisoccursduringaconversion, theconver-
sion is halted and the data bus is put into Hi-Z mode.
–
+
+
ꢀI , ꢀI ꢁPin 4±, Pin 43x: Differential Analog ꢃnputs.
PD ꢁPin 33x: Power-Down ꢃnput. When high, the
LTC2393-16ispowereddownandsubsequentconversion
requests are ignored. ꢂefore entering power shutdown,
the digital output data should be read.
–
ꢃI – (ꢃI ) can range up to ±V
.
REF
CNVST ꢁPin 34x: Conversion Start ꢃnput. A falling edge
on CNVST puts the internal sample-and-hold into the hold
mode and starts a conversion. CNVST is independent of
CS.
239316f
9
LTC2393-16
FUNCTIONAL BLOCK DIAGRAM
AVP DVP OVP
LTC2393-16
16-ꢂꢃT OR
TWO ꢂYTE
SDꢃI
SDOUT
SCLK
+
ꢃI
PARALLELꢄ
SERꢃAL
ꢃITERFACE
16-ꢂꢃT SAMPLꢃIG ADC
16-ꢂꢃT
–
ꢃI
CS
1x ꢂUFFER
RD
REFꢃI
SERꢄPAR
ꢂYTESWAP
Oꢂꢄ2C
REFOUT
VCM
±.ꢀ96V
ꢂUSY
COITROL LOGꢃC
CNVST PD
REFEREICE
REFSEISE
RESET
GID OGID
239316ꢂD
TIMING DIAGRAMS
Conversion Timing Using the Parallel ꢀnterface
CS, RD = ꢀ
CNVST
ACQUꢃRE
ꢂUSY
COIVERT
D[15:ꢀ]
PREVꢃOUS COIVERSꢃOI
CURREIT COIVERSꢃOI
239315 TDꢀ1
Conversion Timing Using the Lerial ꢀnterface
CS, RD = ꢀ
CNVST
ACQUꢃRE
ꢂUSY
COIVERT
SCLK
D1± D12 D1ꢀ D8 D6 D± D2 Dꢀ
D15 D13 D11 D9 D7 D5 D3 D1
SDOUT
239315 TDꢀ2
239316f
10
LTC2393-16
APPLICATIONS INFORMATION
OVERVꢀEW
ꢀ11...111
ꢀ11...11ꢀ
ꢂꢃPOLAR
ZERO
The LTC2393-16 is a low noise, high speed 16-bit suc-
cessive approximation register (SAR) ADC. Operating
from a single 5V supply, the LTC2393-16 supports a
large ±±.ꢀ96V fully differential input range, maꢁing it ideal
for high performance applications which require a wide
dynamicrange.TheLTC2393-16achieves±2LSꢂꢃILmax,
no missing codes at 16 bits and 9±.2dꢂ SIR (typ).
ꢀꢀꢀ...ꢀꢀ1
ꢀꢀꢀ...ꢀꢀꢀ
111...111
111...11ꢀ
1ꢀꢀ...ꢀꢀ1
1ꢀꢀ...ꢀꢀꢀ
FSR = +FS – –FS
1LSꢂ = FSRꢄ65536
The LTC2393-16 includes a precision internal reference
with a guaranteed ꢀ.5% initial accuracy and a ±2ꢀppmꢄ/C
(max)temperaturecoefficient.Fast1Mspsthroughputwith
no cycle latency in both parallel and serial interface modes
maꢁes the LTC2393-16 ideally suited for a wide variety
of high speed applications. An internal oscillator sets the
conversion time, easing external timing considerations.
The LTC2393-16 dissipates only 1±ꢀmW at 1Msps, while
both nap and sleep power-down modes are provided to
further reduce power during inactive periods.
–1 ꢀV
LSꢂ
ꢃIPUT VOLTAGE (V)
1
LSꢂ
–FSRꢄ2
FSRꢄ2 – 1LSꢂ
239316 Fꢀ2
Figure ±. 2TC±393-16 Two’s Complement Transfer Function
AIA2OG ꢀIPUT
The analog inputs of the LTC2393-16 are fully differential
in order to maximize the signal swing that can be digitized.
Theanaloginputscanbemodeledbytheequivalentcircuit
showninFigure3.ThediodesattheinputprovideESDpro-
tection. The analog inputs should not exceed the supply or
gobelowground.ꢃntheacquisitionphase,eachinputsees
approximately±ꢀpF(C )fromthesamplingCDACinseries
with 5ꢀΩ (R ) from the on-resistance of the sampling
switch. Any unwanted signal that is common to both
inputs will be reduced by the common mode rejection of
the ADC. The inputs draw only one small current spiꢁe
COIVERTER OPERATꢀOI
The LTC2393-16 operates in two phases. During the ac-
quisition phase, the charge redistribution capacitor DꢄA
ꢃI
+
–
ꢃI
converter (CDAC) is connected to the ꢃI and ꢃI pins
to sample the differential analog input voltage. A falling
edge on the CNVST pin initiates a conversion. During the
conversionphase,the16-bitCDACissequencedthrougha
successiveapproximationalgorithm,effectivelycomparing
the sampled input with binary-weighted fractions of the
while charging the C capacitors during acquisition.
During conversion, the analog inputs draw only a small
ꢃI
leaꢁage current.
reference voltage (e.g., V ꢄ2, V ꢄ± … V ꢄ65536)
REF
REF
REF
usingthedifferentialcomparator.Attheendofconversion,
the CDAC output approximates the sampled analog input.
The ADC control logic then prepares the 16-bit digital
output code for parallel or serial transfer.
AVP
C
ꢃI
R
ꢃI
R
ꢃI
+
–
ꢃI
ꢂꢃAS
AVP
VOLTAGE
C
TRAILFER FUICTꢀOI
ꢃI
239316 Fꢀ3
ꢃI
The LTC2393-16 digitizes the full-scale voltage of 2 • V
REF
REF
16
into2 levels,resultinginanLSꢂsizeof125μVwhenV
=±.ꢀ96V. Theidealtransferfunctionfortwo’scomplement
is shown in Figure 2. The Oꢂꢄ2C pin selects either offset
binary or two’s complement format.
Figure 3. The Equivalent Circuit for the
Differential Analog ꢀnput of the 2TC±393-16
239316f
11
LTC2393-16
APPLICATIONS INFORMATION
ꢀIPUT DRꢀVE CꢀRCUꢀTL
distortion from self heating and from damage that may
occurduringsoldering.Metalfilmsurfacemountresistors
are much less susceptible to both problems.
Alowimpedancesourcecandirectlydrivethehighimped-
ance inputs of the LTC2393-16 without gain error. A high
impedance source should be buffered to minimize settling
time during acquisition and to optimize the distortion
performance of the ADC.
Lingle-to-Differential Conversion
For single-ended input signals, a single-ended-to-differ-
ential conversion circuit must be used to produce a dif-
ferentialsignalattheADCinputs.TheLT635ꢀADCdriveris
recommendedforperformingasingle-ended-to-differential
conversion, as shown in Figure ±a. ꢃts low noise and good
DC linearity allows the LTC2393-16 to meet full data sheet
specifications. An alternative solution using two op amps
is shown in Figure ±b. Using two LT18ꢀ6 op amps, the
circuit achieves 9±.1dꢂ signal-to-noise ratio (SIR). For a
2ꢀꢁHz input signal, the input of the LTC2393-16 has been
bandwidth limited to about 25ꢁHz.
For best performance, a buffer amplifier should be used
to drive the analog inputs of the LTC2393-16. The am-
plifier provides low output impedance to allow for fast
settling of the analog signal during the acquisition phase.
ꢃt also provides isolation between the signal source and
the ADC inputs which draw a small current spiꢁe during
acquisition.
ꢀnput Filtering
The noise and distortion of the buffer amplifier and other
circuitry must be considered since they add to the ADC
noiseanddistortion.Ioisyinputcircuitryshouldbefiltered
prior to the analog inputs to minimize noise. A simple
1-pole RC filter is sufficient for many applications.
ADC REFEREICE
A low noise, low temperature drift reference is critical to
achieving the full data sheet performance of the ADC. The
LTC2393-16 provides an excellent internal reference with
a ±2ꢀppmꢄ/C (max) temperature coefficient. For better
accuracy, an external reference can be used.
Large filter RC time constants slow down the settling at
the analog inputs. ꢃt is important that the overall RC time
constants be short enough to allow the analog inputs to
completely settle to 16-bit resolution within the acquisi-
The high speed, low noise internal reference buffer is used
for both internal and external reference applications. ꢃt
cannot be bypassed.
tion time (t ).
ACQ
Highqualitycapacitorsandresistorsshouldbeusedinthe
RC filter since these components can add distortion. IPO
and silver mica type dielectric capacitors have excellent
linearity. Carbon surface mount resistors can generate
AIALOG
ꢃIPUT
+
ꢀV TO ±.ꢀ96V
LT18ꢀ6
–
2±9Ω
+
ꢃI
3ꢀ1Ω
ꢀ.ꢀ13μF
2±9Ω
LTC2393-16
+
ꢃI
3ꢀ1Ω
2±9Ω
–
ꢃI
AIALOG ꢃIPUT
ꢀV TO ±.ꢀ96V
22ꢀꢀpF
LT635ꢀ
LTC2393-16
239316 Fꢀ±b
2±9Ω
–
–
+
ꢃI
LT18ꢀ6
239316 Fꢀ±a
COMMOI
MODE
VOLTAGE
SꢃIGLE-EIDED-
TO-DꢃFFEREITꢃAL
DRꢃVER
Figure 4a. Recommended Lingle-Ended-to-Differential
Conversion Circuit Using the 2T6350 ADC Driver
Figure 4b. Alternative Lingle-Ended-to-Differential Conversion
Circuit Using Two 2T1806 Op Amps
239316f
12
LTC2393-16
APPLICATIONS INFORMATION
ꢀnternal Reference
DYIAMꢀC PERFORMAICE
To use the internal reference, simply tie the REFOUT and
REFꢃI pins together. This connects the ±.ꢀ96V output of
the internal reference to the input of the internal reference
buffer. The output impedance of the internal reference is
approximately 2.6ꢁΩ and the input impedance of the in-
ternal reference buffer is about 85ꢁΩ. ꢃt is recommended
that this node be bypassed to ground with a 1μF or larger
capacitortofiltertheoutputnoiseoftheinternalreference.
The REFSEISE pin should be left floating when using the
internal reference.
Fast fourier transform (FFT) techniques are used to test
the ADC’s frequency response, distortion and noise at the
rated throughput. ꢂy applying a low distortion sine wave
and analyzing the digital output using an FFT algorithm,
the ADC’s spectral content can be examined for frequen-
cies outside the fundamental. The LTC2393-16 provides
guaranteed tested limits for both AC distortion and noise
measurements.
Lignal-to-Ioise and Distortion Ratio ꢁLꢀIADx
The signal-to-noise and distortion ratio (SꢃIAD) is the
ratiobetweentheRMSamplitudeofthefundamentalinput
frequency and the RMS amplitude of all other frequency
components at the AꢄD output. The output is band-limited
tofrequenciesfromaboveDCandbelowhalfthesampling
frequency. Figure 5 shows that the LTC2393-16 achieves
a typical SꢃIAD of 93.9dꢂ at a 1MHz sampling rate with
a 2ꢀꢁHz input.
Eꢂternal Reference
An external reference can be used with the LTC2393-16
when even higher performance is required. The
LT179ꢀ-±.ꢀ96 offers ꢀ.ꢀ5% (max) initial accuracy and
1ꢀppmꢄ/C (max) temperature coefficient. When using an
external reference, connect the reference output to the
REFꢃI pin and connect the REFOUT pin to ground. The
REFSEISE pin should be connected to the ground of the
external reference.
ꢀ
–2ꢀ
SIR = 9±.2dꢂ
THD ꢀ –1ꢀ5dꢂ
SꢃIAD = 93.9dꢂ
SFDR = 1ꢀ8dꢂ
–±ꢀ
–6ꢀ
–8ꢀ
–1ꢀꢀ
–12ꢀ
–1±ꢀ
–16ꢀ
–18ꢀ
ꢀ
±ꢀꢀ
5ꢀꢀ
1ꢀꢀ
2ꢀꢀ
3ꢀꢀ
FREQUEICY (ꢁHz)
239316 Gꢀ8
Figure 5. 16k Point FFT of the 2TC±393-16, fL = 1Msps, fꢀI = ±0kHz
239316f
13
LTC2393-16
APPLICATIONS INFORMATION
Lignal-to-Ioise Ratio ꢁLIRx
Power Lupply Lequencing
The signal-to-noise ratio (SIR) is the ratio between the
RMS amplitude of the fundamental input frequency and
the RMS amplitude of all other frequency components
except the first five harmonics and DC. Figure 5 shows
that the LTC2393-16 achieves a typical SIR of 9±.2dꢂ at
a 1MHz sampling rate with a 2ꢀꢁHz input.
The LTC2393-16 does not have any specific power sup-
ply sequencing requirements. Care should be taꢁen to
observe the maximum voltage relationships described in
the Absolute Maximum Ratings section. The LTC2393-16
has a power-on-reset (POR) circuit. With the POR, the
result of the first conversion is valid after power has
been applied to the ADC. The LTC2393-16 will reset itself
if the power supply voltage drops below 2.5V. Once the
supply voltage is brought bacꢁ to its nominal value, the
POR will reinitialize the ADC and it will be ready to start
a new conversion.
Total Harmonic Distortion ꢁTHDx
Totalharmonicdistortion(THD)istheratiooftheRMSsum
ofallharmonicsoftheinputsignaltothefundamentalitself.
The out-of-band harmonics alias into the frequency band
between DC and half the sampling frequency (f
THD is expressed as:
ꢄ2).
SMPL
Iap Mode
The LTC2393-16 can be put into the nap mode after a
conversion has been completed to reduce the power
consumption between conversions. ꢃn this mode some
of the circuitry on the device is turned off. Iap mode is
enabledbyꢁeepingCNVSTlowbetweenconversions.When
the next conversion is requested, bring CNVST high and
hold for at least 25ꢀns, then start the next conversion by
bringing CNVST low. See Figure 6.
2
2
2
2
V2 + V3 + V4 ...VN
THD= 20 log
V1
where V is the RMS amplitude of the fundamental fre-
1
quencyandV throughV aretheamplitudesofthesecond
2
I
through Ith harmonics.
POWER COILꢀDERATꢀOIL
Power Lhutdown Mode
The LTC2393-16 provides three sets of power supply
pins: the analog 5V power supply (AVP), the digital 5V
power supply (DVP) and the digital inputꢄoutput interface
power supply (OVP). The flexible OVP supply allows the
LTC2393-16tocommunicatewithanydigitallogicoperating
between 1.8V and 5V, including 2.5V and 3.3V systems.
When PD is tied high, the LTC2393-16 enters power shut-
downandsubsequentrequestsforconversionareignored.
ꢂefore entering power shutdown, the digital output data
needstoberead.However,ifarequestforpowershutdown
(PD = high) occurs during a conversion, the conversion
t
5
CNVST
ꢂUSY
IAP
t
t
ACQ
COIV
IAP MODE
239316 Fꢀ6
Figure 6. Iap Mode Timing for the 2TC±393-16
239316f
14
LTC2393-16
APPLICATIONS INFORMATION
will finish and then the device will power down. The data
from that conversion can be read after PD = low is applied.
ꢃn this mode power consumption drops to a typical value
of 175μW from 1±ꢀmW. This mode can be used if the
LTC2393-16 is inactive for a long period of time and the
user wants to minimize the power dissipation.
TꢀMꢀIG AID COITRO2
The LTC2393-16 conversion is controlled by CNVST. A
falling edge on CNVST will start a conversion. CS and RD
control the digital interface on the LTC2393-16. When
either CS or RD is high, the digital outputs are high
impedance.
Recovery from Power Lhutdown Mode
CNVST Timing
Once the PD pin is returned to a low level, ending the
power shutdown request, the internal circuitry will begin
to power up. ꢃf the internal reference is used, the 2.6ꢁΩ
output impedance with the 1μF bypass capacitor on the
REFꢃIꢄREFOUT pins will be the main time constant for
the power-on recovery time. ꢃf an external reference is
used, typically allow 5ms for recovery before initiating a
new conversion.
The LTC2393-16 conversion is controlled by CNVST. A
falling edge on CNVST will start a conversion. Once a
conversion has been initiated, it cannot be restarted until
the conversion is complete. For optimum performance
CNVSTshouldbeacleanlowjittersignal. Converterstatus
is indicated by the ꢂUSY output which remains high while
the conversion is in progress. To ensure no errors occur
in the digitized results return the rising edge either within
±ꢀns from the start of the conversion or wait until after
the conversion has been completed. The CNVST timing
needed to taꢁe advantage of the reduced power mode of
operation is described in the Iap Mode section.
Power Dissipation vs Lampling Frequency
The power dissipation of the LTC2393-16 will decrease
as the sampling frequency is reduced when nap mode
is activated. See Figure 7. ꢃn nap mode, a portion of the
circuitryontheLTC2393-16isturnedoffafteraconversion
has been completed. ꢃncreasing the time allowed between
conversions lowers the average power.
ꢀnternal Conversion Clock
The LTC2393-16 has an internal clocꢁ that is trimmed
to achieve a maximum conversion time of 6ꢀꢀns. Io
external adjustments are required and with a maximum
acquisition time of 385ns, a throughput performance of
1Msps is guaranteed.
3ꢀ
25
2ꢀ
DꢀGꢀTA2 ꢀITERFACE
15
1ꢀ
The LTC2393-16 allows both parallel and serial digital
interfaces. TheflexibleOVPsupplyallowstheLTC2393-16
to communicate with any digital logic operating between
1.8V and 5V, including 2.5V and 3.3V systems.
5
ꢀ
ꢀ.1
1
1ꢀ
1ꢀꢀ
1ꢀꢀꢀ
SAMPLꢃIG FREQUEICY (ꢁHz)
239316 G15
Figure 7. Power Dissipation of the 2TC±393-16
Decreases with Decreasing Lampling Frequency
239316f
15
LTC2393-16
APPLICATIONS INFORMATION
Parallel Modes
The SDꢃI input pin is used to daisy-chain multiple con-
verters. This is useful for applications where hardware
constraints may limit the number of lines needed to
interface to a large number of converters. For example,
if two devices are cascaded, the MSꢂ of the first device
will appear at the output after 17 SCLK cycles. The first
MSꢂ is clocꢁed in on the falling edge of the first SCLK.
See Figure 12.
The parallel output data interface is active when the
SERꢄPAR pin is tied low and when both CS and RD are low.
The output data can be read as a 16-bit word as shown
in Figures 8, 9 and 1ꢀ or it can be read as two 8-bit bytes
by using the ꢂYTESWAP pin. As shown in Figure 11, with
the ꢂYTESWAP pin low, the first eight MSꢂs are output on
the D15 to D8 pins and the eight LSꢂs are output on the
D7 to DO pins. When ꢂYTESWAP is taꢁen high, the eight
LSꢂs now are output on the D15 to D8 pins and the eight
MSꢂs are output on the D7 to Dꢀ pins.
Data Format
When Oꢂꢄ2C is high, the digital output is offset binary.
When low, the MSꢂ is inverted resulting in two’s comple-
ment output. This pin is active in both the parallel and
serial modes of operation.
Lerial Modes
The serial output data interface is active when the
SERꢄPAR pinistiedhighandwhenbothCSandRDarelow.
The serial output data will be clocꢁed out on the SDOUT
pin when an external clocꢁ is applied to the SCLK pin.
Clocꢁing out the data after the conversion will yield the
best performance. With a shift clocꢁ frequency of at least
±ꢀMHz, a 1Msps throughput is still achieved. The serial
output data changes state on the rising edge of SCLK and
can be captured on the falling edge of SCLK. D15 remains
valid till the first rising edge of shift clocꢁ after the first
falling edge of shift clocꢁ. The non-active digital outputs
are high impedance when operating in the serial mode.
Reset
When the RESET pin is high, the LTC2393-16 is reset, and
ifthisoccursduringaconversion, theconversionishalted
and the data bus is put into Hi-Z mode. ꢃn reset, requests
fornewconversionsareignored.OnceRESETreturnslow,
the LTC2393-16 is ready to start a new conversion after
the acquisition time has been met. See Figure 13.
CS = RD = ꢀ
t
±
CNVST
ꢂUSY
t
COIV
t
16
t
6
PREVꢃOUS COIVERSꢃOI
IEW
DATA ꢂUS D[15:ꢀ]
239316 Fꢀ8
Figure 8. Read the Parallel Data Continuously.
The Data Sus is Always Driven and Can’t Se Lhared
239316f
16
LTC2393-16
APPLICATIONS INFORMATION
CS
RD
ꢂUSY
Hi-Z
Hi-Z
CURREIT
COIVERSꢃOI
DATA ꢂUS D[15:ꢀ]
239316 Fꢀ9
t
17
t
18
Figure 9. Read the Parallel Data After the Conversion
CS = ꢀ
t
±
CNVST, RD
ꢂUSY
t
COIV
t
6
Hi-Z
Hi-Z
PREVꢃOUS
COIVERSꢃOI
DATA ꢂUS D[15:ꢀ]
239316 Fꢀ9
t
t
18
17
Figure 10. Read the Parallel Data During the Conversion
8-ꢂꢃT ꢃITERFACE
CS, RD
ꢂYTESWAP
D[15:8]
Hi-Z
Hi-Z
HꢃGH ꢂYTE
LOW ꢂYTE
239316 F11
t
t
17
t
18
17
Figure 11. 8-Sit Parallel ꢀnterface Using the SYTELWAP Pin
239316f
17
LTC2393-16
APPLICATIONS INFORMATION
RD = ꢀ
SCLK STARTS LOW
t
15
CS
ꢂUSY
t
8
t
1ꢀ
t
9
SCLK
1
2
3
±
15
16
17
18
t
13
SDOUT
(ADC 2)
Hi-Z
D15
D1±
D13
D1
Dꢀ
X15
X1±
t
t
12
1±
t
11
SDꢃI
(ADC 2)
X15
X1±
X13
X1
Xꢀ
RD = ꢀ
SCLK STARTS HꢃGH
CS
ꢂUSY
t
8
t
1ꢀ
t
9
SCLK
1
2
3
±
15
16
17
18
t
13
Hi-Z
SDOUT
(ADC 2)
D15
D1±
D13
D1
Dꢀ
X15
X1±
t
t
12
1±
t
11
SDꢃI
(ADC 2)
X15
X1±
X13
X1
Xꢀ
CNVST ꢃI
CS ꢃI
RD ꢃI
SCLK ꢃI
LTC2393-16
LTC2393-16
CNVST
CNVST
CS
CS
RD
SCLK
SDꢃI SDOUT
RD
SCLK
SDꢃI SDOUT
DATA OUT
239316 F12
ADC 1
ADC 2
Figure 1±. Lerial ꢀnterface with Eꢂternal Clock. Read After
the Conversion. Daisy-Chain Multiple Converters
239316f
18
LTC2393-16
APPLICATIONS INFORMATION
t
7
RESET
t
ACQ
CVNST
Hi-Z
DATA ꢂUS D[15:ꢀ]
239316 F13
Figure 13. RELET Pin Timing
239316f
19
LTC2393-16
APPLICATIONS INFORMATION
SOARD 2AYOUT
Recommended 2ayout
To obtain the best performance from the LTC2393-16, a
printed circuit board (PCꢂ) is recommended. Layout for
the printed circuit board should ensure the digital and
analog signal lines are separated as much as possible.
ꢃn particular, care should be taꢁen not to run any digital
clocꢁs or signals alongside analog signals or underneath
the ADC.
ThefollowingisanexampleofarecommendedPCꢂlayout.
A single solid ground plane is used. ꢂypass capacitors to
the supplies are placed as close as possible to the supply
pins. Low impedance common returns for these bypass
capacitors are essential to the low noise operation of the
ADC. The analog input traces are screened by ground.
For more details and information refer to DC15ꢀꢀA, the
evaluation ꢁit for the LTC2393-16
Partial Lchematic of Demoboard
C36
1μF
CNVST
3±
39
REFSEISE
38
37
CNVST
REFꢃI
REFOUT
R2
2±9Ω
1%
29
28
27
26
25
2±
23
22
21
16
15
1±
13
12
11
1ꢀ
9
ꢂUSY
D15
D1±
D13
D12
ꢂUSY
D15
±3
D1±
+
ꢃI
D13
D12
C5±
OPT
D11ꢄSCLK
D11ꢄSCLK
D1ꢀꢄSDOUT
D9ꢄSDꢃI
D8
D1ꢀꢄSDOUT
D9ꢄSDꢃI
D8
C2
D7
D7
LTC2393-16
22ꢀꢀpF
12ꢀ6 IPO
D6
D6
D5
D5
D±
D±
R3
2±9Ω
1%
D3
D3
D2
D1
D2
D1
±±
–
ꢃI
Dꢀ
Dꢀ
8
C55
OPT
ꢂYTESWAP
GID
7
VCM Oꢂꢄ2C GID SERꢄPAR RESET PD CS RD
36
6
5
±
32 33
31 3ꢀ
C53
1ꢀμF
C31
ꢀ.1μF
C3ꢀ
1ꢀμF
C29
ꢀ.1μF
C28
1ꢀμF
R2±
1.ꢀΩ
3.3V
5V
C±ꢀ
±.7μF
±7
±6 ±5 ±ꢀ
2
19
3
18
AVPꢄAVL AVP AVP AVP AVP
DVP DVPꢄDVL OVP
LTC2393-16
GID GID GID GID GID GID OGID
±8 ±± ±1 35 2ꢀ 17
239316 TAꢀ2
1
239316f
20
LTC2393-16
APPLICATIONS INFORMATION
Partial Top Lilkscreen
Partial 2ayer 1 Component Lide
Partial 2ayer ± Ground Plane
239316f
21
LTC2393-16
PACKAGE DESCRIPTION
UK Package
48-2ead Plastic QFI ꢁ7mm × 7mmx
(Reference LTC DWG # ꢀ5-ꢀ8-17ꢀ±)
ꢀ.7ꢀ pꢀ.ꢀ5
5.15 p ꢀ.ꢀ5
5.5ꢀ REF
6.1ꢀ pꢀ.ꢀ5 7.5ꢀ pꢀ.ꢀ5
(± SꢃDES)
5.15 p ꢀ.ꢀ5
PACKAGE OUTLꢃIE
ꢀ.25 pꢀ.ꢀ5
ꢀ.5ꢀ ꢂSC
RECOMMEIDED SOLDER PAD PꢃTCH AID DꢃMEISꢃOIS
APPLY SOLDER MASK TO AREAS THAT ARE IOT SOLDERED
ꢀ.75 p ꢀ.ꢀ5
R = ꢀ.115
TYP
7.ꢀꢀ p ꢀ.1ꢀ
(± SꢃDES)
R = ꢀ.1ꢀ
TYP
±7 ±8
ꢀ.±ꢀ p ꢀ.1ꢀ
PꢃI 1 TOP MARK
(SEE IOTE 6)
1
2
PꢃI 1
CHAMFER
C = ꢀ.35
5.15 p ꢀ.1ꢀ
5.5ꢀ REF
(±-SꢃDES)
5.15 p ꢀ.1ꢀ
(UK±8) QFI ꢀ±ꢀ6 REV C
ꢀ.2ꢀꢀ REF
ꢀ.25 p ꢀ.ꢀ5
ꢀ.5ꢀ ꢂSC
ꢂOTTOM VꢃEW—EXPOSED PAD
ꢀ.ꢀꢀ – ꢀ.ꢀ5
IOTE:
1. DRAWꢃIG COIFORMS TO JEDEC PACKAGE OUTLꢃIE MO-22ꢀ VARꢃATꢃOI (WKKD-2)
2. DRAWꢃIG IOT TO SCALE
3. ALL DꢃMEISꢃOIS ARE ꢃI MꢃLLꢃMETERS
±. DꢃMEISꢃOIS OF EXPOSED PAD OI ꢂOTTOM OF PACKAGE DO IOT ꢃICLUDE
MOLD FLASH. MOLD FLASH, ꢃF PRESEIT, SHALL IOT EXCEED ꢀ.2ꢀmm OI AIY SꢃDE, ꢃF PRESEIT
5. EXPOSED PAD SHALL ꢂE SOLDER PLATED
6. SHADED AREA ꢃS OILY A REFEREICE FOR PꢃI 1 LOCATꢃOI OI THE TOP AID ꢂOTTOM OF PACKAGE
239316f
22
LTC2393-16
PACKAGE DESCRIPTION
2X Package
48-2ead Plastic 2QFP ꢁ7mm × 7mmx
(Reference LTC DWG # ꢀ5-ꢀ8-176ꢀ Rev Ø)
7.15 – 7.25
5.5ꢀ REF
9.ꢀꢀ ꢂSC
7.ꢀꢀ ꢂSC
±8
±8
1
2
SEE IOTE: ±
1
2
ꢀ.5ꢀ ꢂSC
9.ꢀꢀ ꢂSC
7.ꢀꢀ ꢂSC
5.5ꢀ REF
7.15 – 7.25
ꢀ.2ꢀ – ꢀ.3ꢀ
A
A
PACKAGE OUTLꢃIE
Cꢀ.3ꢀ – ꢀ.5ꢀ
1.3ꢀ MꢃI
RECOMMEIDED SOLDER PAD LAYOUT
APPLY SOLDER MASK TO AREAS THAT ARE IOT SOLDERED
1.6ꢀ
11/ – 13/
1.35 – 1.±5 MAX
Rꢀ.ꢀ8 – ꢀ.2ꢀ
GAUGE PLAIE
ꢀ.25
ꢀ/ – 7/
11/ – 13/
1.ꢀꢀ REF
ꢀ.5ꢀ
ꢂSC
ꢀ.ꢀ9 – ꢀ.2ꢀ
ꢀ.17 – ꢀ.27
ꢀ.ꢀ5 – ꢀ.15
LX±8 LQFP ꢀ9ꢀ7 REVØ
ꢀ.±5 – ꢀ.75
SECTꢃOI A – A
IOTE:
1. PACKAGE DꢃMEISꢃOIS COIFORM TO JEDEC #MS-ꢀ26 PACKAGE OUTLꢃIE
2. DꢃMEISꢃOIS ARE ꢃI MꢃLLꢃMETERS
±. PꢃI-1 ꢃIDEITꢃFꢃER ꢃS A MOLDED ꢃIDEITATꢃOI, ꢀ.5ꢀmm DꢃAMETER
5. DRAWꢃIG ꢃS IOT TO SCALE
3. DꢃMEISꢃOIS OF PACKAGE DO IOT ꢃICLUDE MOLD FLASH. MOLD FLASH
SHALL IOT EXCEED ꢀ.25mm OI AIY SꢃDE, ꢃF PRESEIT
239316f
ꢃnformation furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation maꢁes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
23
LTC2393-16
TYPICAL APPLICATION
ADC Driver: Lingle-Ended ꢀnput to Differential Output
5V
2±9Ω
ꢀ.1μF
V
ꢃI
+
5V
+
+
ꢃI1
ꢀV to ±V –
SHDN
V
OUT2
+
–
–
A
ꢃI
22ꢀꢀpF
LTC2393-16
+
–
+
LT635ꢀ
A
ꢃI
–
+
–
V
OUT1
2±9Ω
ꢃI2
ꢃI1
239316 TAꢀ3
ꢀ.1μF
–5V
ꢀ.1μF
±99Ω
2V
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239316f
LT 0110 • PRINTED IN USA
LinearTechnology Corporation
163ꢀ McCarthy ꢂlvd., Milpitas, CA 95ꢀ35-7±17
24
●
●
© LINEAR TECHNOLOGY CORPORATION 2010
(±ꢀ8) ±32-19ꢀꢀ FAX: (±ꢀ8) ±3±-ꢀ5ꢀ7 www.linear.com
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