LTC1740
14-Bit, 6Msps,
Sampling ADC
FEATURES
s
s
s
s
s
s
s
s
s
s
s
s
DESCRIPTIO
6Msps Sample Rate
79dB S/(N + D) and 91dB SFDR at 2.5MHz f
IN
Single 5V Supply or
±5V
Supplies
Integral Nonlinearity Error: < 1LSB
Differential Nonlinearity: < 0.5LSB
80MHz Full-Power Bandwidth Sampling
±2.5V
and
±1.25V
Bipolar Input Ranges
2.5V Signal Ground Available
Out-of-Range Indicator
True Differential Inputs with 75dB CMRR
Power Dissipation: 245mW
36-Pin SSOP Package (0.209 Inch Width)
The LTC
®
1740 is a 6Msps, 14-bit sampling A/D converter
that draws only 245mW from either a single 5V or dual
±5V
supplies. This easy-to-use device includes a high
dynamic range sample-and-hold and a programmable
precision reference.
The LTC1740 has a flexible input circuit that allows differ-
ential full-scale input ranges of
±2.5V
and
±1.25V
with the
internal reference, or any full-scale input range up to
±2.5V
with an external reference. The input common
mode voltage is arbitrary, though a 2.5V reference is
provided for single supply applications.
DC specifications include 1LSB typical INL, 0.5LSB typical
DNL and no missing codes over temperature. Outstanding
AC performance includes 79dB S/(N + D) and 91dB SFDR
at an input frequency of 2.5MHz.
The unique differential input sample-and-hold can acquire
single-ended or differential input signals up to its 80MHz
bandwidth. The 75dB common mode rejection allows
users to eliminate ground loops and common mode noise
by measuring signals differentially from the source. A
separate output logic supply allows direct connection to
3V components.
APPLICATIO S
s
s
s
s
s
Telecommunications
Multiplexed Data Acquisition Systems
High Speed Data Acquisition
Spectral Analysis
Imaging Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
BLOCK DIAGRA
5V
1µF
8
5V
1µF
9
32
33
3V TO 5V
1µF
19
+
V
IN
1000pF
1
+
A
IN
V
DD
V
DD
V
DD
V
DD
OV
DD
OF
36
12
–
1µF
2
3
–A
IN
V
CM
S/H
PIPELINED 14-BIT ADC
D13 (MSB)
–20
AMPLITUDE (dB)
–40
–60
–80
D7
MODE SELECT
DIGITAL CORRECTION
LOGIC
OUTPUT
BUFFERS
D6
18
20
DIGITAL
OUTPUT
4
SENSE
2.5V
REFERENCE
D0 (LSB)
26
5
V
REF
2.250V
BUSY
CLK
27
35
1µF
6MHz CLK
30
V
SS
29
V
SS
6
GND
7
GND
10
GND
34
GND
31
GND
11
OGND
28
OGND
1740 TA01
1µF
0V OR –5V
U
4096-Point FFT
0
f
SMPL
= 6MHz
f
IN
= 2.5MHz, 5V
P-P
5V SUPPLY
–100
–120
0
0.5
1.0
1.5
2.0
FREQUENCY (MHz)
2.5
3.0
1740 TA02
W
U
1740f
1
LTC1740
ABSOLUTE
MAXIMUM
RATINGS
0V
DD
= V
DD
(Notes 1, 2)
PACKAGE/ORDER INFORMATION
TOP VIEW
+A
IN
–A
IN
V
CM
SENSE
V
REF
GND
GND
V
DD
V
DD
1
2
3
4
5
6
7
8
9
36 OF
35 CLK
34 GND
33 V
DD
32 V
DD
31 GND
30 V
SS
29 V
SS
28 OGND
27 BUSY
26 D0
25 D1
24 D2
23 D3
22 D4
21 D5
20 D6
19 OV
DD
Supply Voltage (V
DD
) ................................................. 6V
Negative Supply Voltage (V
SS
) ................................ – 6V
Total Supply Voltage (V
DD
to V
SS
) ........................... 12V
Analog Input Voltage
(Note 3) ......................... (V
SS
– 0.3V) to (V
DD
+ 0.3V)
Digital Input Voltage
(Note 3) ......................... (V
SS
– 0.3V) to (V
DD
+ 0.3V)
Digital Output Voltage ........ (V
SS
– 0.3V) to (V
DD
+ 0.3V)
Power Dissipation .............................................. 500mW
Operating Temperature Range
LTC1740C ............................................... 0°C to 70°C
LTC1740I ............................................ – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC1740CG
LTC1740IG
GND 10
OGND 11
D13 (MSB) 12
D12 13
D11 14
D10 15
D9 16
D8 17
D7 18
G PACKAGE
36-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 95°C/W
Consult LTC Marketing for parts specified with wider operating temperature
ranges.
CO VERTER CHARACTERISTICS
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. With internal 4.500V reference. Specifications are guaranteed for both
dual supply and single supply operation. (Notes 4, 5)
PARAMETER
Resolution (No Missing Codes)
Integral Linearity Error
Differential Linearity Error
Offset Error
Full-Scale Error
Full-Scale Tempco
I
OUT(REF)
= 0
(Note 7)
q
CONDITIONS
q
MIN
14
TYP
1
MAX
±2.5
1.25
±
60
±
80
±
75
UNITS
Bits
LSB
LSB
LSB
LSB
LSB
ppm/°C
(Note 6)
q
–1
0.5
±15
±30
±15
2
U
W
U
U
W W
W
U
1740f
LTC1740
A ALOG I PUT
SYMBOL
V
IN
PARAMETER
Analog Input Range
The
q
denotes specifications which apply over the full operating temperature range, otherwise
specifications are at T
A
= 25°C. Specifications are guaranteed for both dual supply and single supply operation. (Note 4)
CONDITIONS
V
REF
= 4.5V (SENSE = 0V)
V
REF
= 2.25V (SENSE Tied to V
REF
)
External V
REF
(SENSE = 5V)
Between Conversions
During Conversions
q
q
q
q
I
IN
C
IN
t
ACQ
t
AP
t
jitter
CMRR
Analog Input Leakage Current
Analog Input Capacitance
Sample-and-Hold Acquisition Time
Sample-and-Hold Aperture Delay Time
Sample-and-Hold Aperture Delay Time Jitter
Analog Input Common Mode Rejection Ratio
V
SS
< (–A
IN
= +A
IN
) < V
DD
DY A IC ACCURACY
SYMBOL
S/(N + D)
THD
SFDR
PARAMETER
Signal-to-Noise Plus Distortion Ratio
Total Harmonic Distortion
Spurious Free Dynamic Range
Full-Power Bandwidth
Input Referred Noise
I TER AL REFERE CE CHARACTERISTICS
T
A
= 25°C. Specifications are guaranteed for both dual supply and single supply operation. (Note 4)
PARAMETER
V
CM
Output Voltage
V
CM
Output Tempco
V
CM
Line Regulation
V
CM
Output Resistance
V
REF
Output Voltage
CONDITIONS
I
OUT
= 0
I
OUT
= 0
4.75V
≤
V
DD
≤
5.25V
– 5.25V
≤
V
SS
≤
– 4.75V
0.1mA
≤
I
OUT
≤
0.1mA
SENSE = GND, I
OUT
= 0
SENSE = V
REF
, I
OUT
= 0
SENSE = V
DD
MIN
2.475
TYP
2.500
±15
0.6
0.03
8
4.500
2.250
Drive V
REF
with
External Reference
±15
MAX
2.525
UNITS
V
ppm/°C
mV/V
mV/V
Ω
V
V
V
ppm/°C
V
REF
Output Tempco
U
U
W U
U
U
MIN
TYP
±2.50
±1.25
±V
REF
/1.8
MAX
UNITS
V
V
V
±10
12
4
67
– 900
0.6
75
µA
pF
pF
ns
ps
ps
RMS
dB
V
DD
= OV
DD
= 5V, V
SS
= 0V, V
REF
= 4.5V, A
IN
= – 0.1dBFS, AC coupled differential input.
CONDITIONS
1MHz Input Signal
2.5MHz Input Signal
1MHz Input Signal, First 5 Harmonics
2.5MHz Input Signal, First 5 Harmonics
1MHz Input Signal
2.5MHz Input Signal
MIN
TYP
79.1
79.0
– 90
– 89
92
91
80
0.45
MAX
UNITS
dB
dB
dB
dB
dB
dB
MHz
LSB
RMS
U
1740f
3
LTC1740
DIGITAL I PUTS A D DIGITAL OUTPUTS
SYMBOL
V
IH
V
IL
I
IN
C
IN
V
OH
PARAMETER
High Level Input Voltage
Low Level Input Voltage
Digital Input Current
Digital Input Capacitance
High Level Output Voltage
0V
DD
= 4.75V, I
O
= –10µA
0V
DD
= 4.75V, I
O
= –200µA
0V
DD
= 2.7V, I
O
= –10µA
0V
DD
= 2.7V, I
O
= –200µA
0V
DD
= 4.75V, I
O
= 160µA
0V
DD
= 4.75V, I
O
= 1.6mA
0V
DD
= 2.7V, I
O
= 160µA
0V
DD
= 2.7V, I
O
= 1.6mA
V
OUT
= 0V, 0V
DD
= 5V
V
OUT
= V
DD
, 0V
DD
= 5V
q
q
q
q
The
q
denotes specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. Specifications are guaranteed for both dual supply and single
supply operation. (Note 4)
CONDITIONS
V
DD
= 5.25V, V
SS
= 0V
V
DD
= 5.25V, V
SS
= – 5V
V
DD
= 4.75V, V
SS
= 0V
V
DD
= 4.75V, V
SS
= – 5V
V
IN
= 0V to V
DD
q
q
q
q
q
V
OL
Low Level Output Voltage
I
SOURCE
I
SINK
Output Source Current
Output Sink Current
POWER REQUIRE E TS
SYMBOL
V
DD
OV
DD
V
SS
I
DD
I
SS
P
D
PARAMETER
Positive Supply Voltage
Output Supply Voltage
Negative Supply Voltage
Positive Supply Current
Negative Supply Current
Power Dissipation
The
q
denotes specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C. Specifications are guaranteed for both dual supply and single supply operation. (Note 4)
CONDITIONS
(Note 9)
(Note 9)
Dual Supply Mode
Single Supply Mode
q
q
q
TI I G CHARACTERISTICS
SYMBOL
f
SAMPLE
t
CONV
t
ACQ
t
H
t
L
t
AP
t
1
t
2
PARAMETER
Sampling Frequency
Conversion Time
Acquisition Time
CLK High Time
CLK Low Time
Aperature Delay of Sample-and-Hold
CLK↑ to BUSY↓
BUSY↑ to Outputs Valid
Data Latency
The
q
denotes specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. Specifications are guaranteed for both dual supply and single supply operation.
(Note 4)
CONDITIONS
q
q
4
U W
U
U
MIN
2.4
2.4
TYP
MAX
UNITS
V
V
0.8
0.8
±10
1.8
4.0
2.3
0.05
0.10
0.05
0.10
50
35
0.4
0.4
4.74
4.71
2.6
V
V
µA
pF
V
V
V
V
V
V
V
V
mA
mA
MIN
4.75
2.7
– 5.25
TYP
MAX
5.25
V
DD
– 4.75
UNITS
V
V
V
V
mA
mA
mW
0
47
2.3
245
60
2.6
300
UW
MIN
0.05
TYP
100
MAX
6
135
UNITS
MHz
ns
ns
ns
ns
ps
ns
ns
Cycles
1740f
(Note 9)
(Note 9)
(Note 9)
q
q
q
31
20
20
67
83.3
83.3
– 900
3.5
1.5
3
LTC1740
TI I G CHARACTERISTICS
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
All voltage values are with respect to ground with GND and OGND
wired together (unless otherwise noted).
Note 3:
When these pin voltages are taken below V
SS
or above V
DD
, they
will be clamped by internal diodes. This product can handle input currents
greater than 100mA below V
SS
or above V
DD
without latchup.
Note 4:
V
DD
= 5V, V
SS
= –5V or 0V, f
SAMPLE
= 6MHz, t
r
= t
f
= 5ns unless
otherwise specified.
Note 5:
Linearity, offset and full-scale specifications apply for a
single-ended +A
IN
input with – A
IN
tied to V
CM
for single supply and 0V for
dual supply.
Note 6:
Integral 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.
Note 7:
Bipolar offset is the offset voltage measured from –0.5LSB
when the output code flickers between 00 0000 0000 0000 and
11 1111 1111 1111.
Note 8:
Guaranteed by design, not subject to test.
Note 9:
Recommended operating conditions.
TYPICAL PERFOR A CE CHARACTERISTICS
Typical INL at 6Msps
2.0
1.5
1.0
DNL (LSB)
INL (LSB)
0.5
0
–0.5
–1.0
–1.5
–2.0
0
4096
8192
CODE
1740 G01
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
S/(N + D) (dBc)
12288
S/(N + D) vs Input Frequency
and Amplitude
80
V
IN
= 0dBFS
75
V
IN
= –6dBFS
AMPLITUDE (dB)
75
70
65
60
55
DUAL SUPPLIES
5V INPUT RANGE
A
IN
= 0dBFS
DIFFERENTIAL INPUT
6Msps
0.1
1
10
INPUT FREQUENCY (MHz)
100
1740 G05
AMPLITUDE (dB)
S/(N + D) (dBc)
70
65
V
IN
= –20dBFS
60
55
50
SINGLE SUPPLY
5V INPUT RANGE
DIFFERENTIAL INPUT
6Msps
0.1
1
10
INPUT FREQUENCY (MHz)
100
1740 G04
U W
UW
Typical DNL at 6Msps
1.0
0.8
0.6
0.4
75
80
S/(N + D) vs Input Frequency
and Amplitude
V
IN
= 0dBFS
V
IN
= –6dBFS
70
65
60
55
50
V
IN
= –20dBFS
DUAL SUPPLIES
5V INPUT RANGE
DIFFERENTIAL INPUT
6Msps
0.1
1
10
INPUT FREQUENCY (MHz)
100
1740 G03
16384
0
4096
8192
CODE
12288
16384
1740 G02
SFDR and THD
vs Input Frequency
95
90
SFDR
85
–THD
80
80
75
70
65
60
55
50
85
95
90
SFDR and THD
vs Input Frequency
SFDR
–THD
SINGLE SUPPLY
5V INPUT RANGE
A
IN
= 0dBFS
DIFFERENTIAL INPUT
6Msps
0.1
1
10
INPUT FREQUENCY (MHz)
100
1740 G06
50
1740f
5
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