LTC1420
12-Bit, 10Msps,
Sampling ADC
FEATURES
s
s
s
s
s
s
s
s
s
s
s
s
DESCRIPTIO
10Msps Sample Rate
Single 5V Supply or
±
5V Supplies
Integral Nonlinearity Error <0.35LSB
Differential Nonlinearity <0.25LSB
71dB S/(N + D) and 83dB SFDR at Nyquist
100MHz Full-Power Bandwidth Sampling
±2.048V, ±1.024V
and
±0.512V
Bipolar Input Range
Input PGA
Out-of-Range Indicator
True Differential Inputs with 75dB CMRR
Power Dissipation: 250mW
28-Pin Narrow SSOP Package
The LTC
®
1420 is a 10Msps, 12-bit sampling A/D converter
that draws only 250mW from either single 5V or dual
±5V
supplies. This easy-to-use device includes a high dynamic
range sample-and-hold, a precision reference and a PGA
input circuit.
The LTC1420 has a flexible input circuit that allows full-
scale input ranges of
±2.048V ±1.024V
and
±0.512V.
The
input common mode voltage is arbitrary, though a 2.5V
reference is provided for single supply applications. The
input PGA has a digitally selectable 1x or 2x gain.
Maximum DC specs include
±1LSB
INL and
±1LSB
DNL
over temperature. Outstanding AC performance includes
71dB S/(N + D) and 83dB SFDR at the Nyquist input
frequency of 5MHz.
The unique differential input sample-and-hold can acquire
single-ended or differential input signals up to its 100MHz
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
s
Telecommunications
Digital Signal Processing
Multiplexed Data Acquisition Systems
High Speed Data Acquisition
Spectral Analysis
Imaging Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
5V
1µF
28
GAIN
5V
1µF
7
V
DD
5V
1µF
23
V
DD
22
OV
DD
OPTIONAL 3V
LOGIC SUPPLY
+
VIN
1 +
A
IN
S/H
2 –A
IN
3 V
CM
PIPELINED 12-BIT ADC
OF 27
D11 (MSB) 10
INL (LSBs)
–
1µF
OUTPUT
BUFFERS
MODE SELECT
DIGITAL CORRECTION
LOGIC
D0 (LSB) 20
CLK 26
DIGITAL
OUTPUT
4 SENSE
2.5V
REFERENCE
5 V
REF
1µF
2.048V
10MHz CLK
V
SS
25
1µF
0V OR –5V
GND
6
GND
8
GND
24
OGND
21
1420 TA01
U
Typical INL Curve
1.00
0.75
0.50
0.25
0
–0.25
–0.50
–0.75
–1.00
0
1024
2048
CODE
3072
4096
1420 TA02
U
U
1
LTC1420
ABSOLUTE
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
+A
IN
–A
IN
V
CM
SENSE
V
REF
GND
V
DD
GND
D11 (MSB)
1
2
3
4
5
6
7
8
9
28 GAIN
27 OF
26 CLK
25 V
SS
24 GND
23 V
DD
22 OV
DD
21 OGND
20 D0
19 D1
18 D2
17 D3
16 D4
15 D5
0V
DD
= V
DD
(Notes 1, 2)
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 4) ............................. (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
LTC1420C ............................................... 0°C to 70°C
LTC1420I ............................................ – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC1420CGN
LTC1420IGN
D10 10
D9 11
D8 12
D7 13
D6 14
GN PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 110°C,
θ
JA
= 110°C/W
Consult factory for Military grade parts.
CONVERTER CHARACTERISTICS
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. With Internal 4.096V Reference. Specifications are guaranteed for both
dual supply and single supply operation. (Note 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 8)
q
CONDITIONS
q
MIN
12
q
q
TYP
±0.35
±0.25
±5
±10
±15
MAX
±1
±1
12
16
30
UNITS
Bits
LSB
LSB
LSB
LSB
LSB
ppm/°C
(Note 7)
A ALOG I PUT
SYMBOL
V
IN
PARAMETER
The
q
denotes the 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 5)
CONDITIONS
V
REF
= 4.096V (SENSE = 0V), GAIN = 5V (1×)
V
REF
= 4.096V (SENSE = 0V), GAIN = 0V (2×)
V
REF
= 2.048V (SENSE = V
REF
), GAIN = 5V (1×)
V
REF
= 2.048V (SENSE = V
REF
), GAIN = 0V (2×)
External V
REF
(SENSE = 5V), GAIN = 5V (1×)
External V
REF
(SENSE = 5V), GAIN = 0V (2×)
Between Conversions
During Conversions
q
q
q
q
q
q
q
MIN
TYP
±2.048
±1.024
±1.024
±0.512
±V
REF
/2
±V
REF
/4
MAX
UNITS
V
V
V
V
V
V
Analog Input Range (Note 9)
+A
IN
– (–A
IN
)
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
–2.048V < (–A
IN
= +A
IN
) < 2.048V
±20
12
6
30
– 250
0.6
75
2
U
µA
pF
pF
ns
ps
ps
dB
W
U
U
W W
W
U
U
U
LTC1420
DY A IC ACCURACY
SYMBOL
S/(N + D)
THD
SFDR
IMD
PARAMETER
The
q
denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C. V
DD
= 5V, V
SS
= – 5V, f
SAMPLE
= 10MHz, V
REF
= 4.096V. + A
IN
= – 0.1dBFS single ended input,
– A
IN
= 0V. (Note 6)
CONDITIONS
1MHz Input Signal
5MHz Input Signal
1MHz Input Signal, First 5 Harmonics
5MHz Input Signal, First 5 Harmonics
1MHz Input Signal
5MHz Input Signal
f
IN1
= 29.37kHz, f
IN2
= 32.446kHz
±2.048V
Input Range
±1.024V
Input Range, 2x Mode (SENSE = GAIN = 0V)
1.5x FS Input to 0 (Settling to 1LSB)
Settling to 1LSB
q
q
q
q
q
q
INTERNAL REFERENCE CHARACTERISTICS
T
A
= 25°C. Specifications are guaranteed for both dual supply and single supply operation. (Note 5)
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
2.50
±15
0.6
0.03
8
4.096
2.048
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
DIGITAL I PUTS A D DIGITAL OUTPUTS
The
q
denotes the 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 5)
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
V
OUT
= V
DD
q
q
q
q
V
OL
Low Level Output Voltage
I
SOURCE
I
SINK
Output Source Current
Output Sink Current
U
U
U
W U
U
MIN
68.5
68
TYP
71.4
71.0
– 84
– 81
– 85
– 83
– 80
100
0.22
0.33
15
15
MAX
UNITS
dB
dB
Signal-to-Noise Plus Distortion Ratio
Total Harmonic Distortion
Peak Harmonic or Spurious Noise
Intermodulation Distortion
Full-Power Bandwidth
Input Referred Noise
Overvoltage Recovery Time
Full-Scale Step Acquisition Time
– 77
– 73
– 78.5
– 75
dB
dB
dB
dB
dB
MHz
LSB
RMS
LSB
RMS
ns
ns
U
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
MIN
2.4
3.5
TYP
MAX
UNITS
V
V
0.8
1
±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
3
LTC1420
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 the 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 5)
CONDITIONS
(Note 10)
(Note 10)
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
PARAMETER
Maximum Sampling Frequency
Conversion Time
Acquisition Time
CLK High Time
CLK Low Time
Aperature Delay of Sample-and-Hold
The
q
denotes the 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 5)
CONDITIONS
q
q
q
q
q
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:
When these pin voltages are taken below V
SS
they will be clamped
by internal diodes. This product can handle input currents greater than
100mA below V
SS
without latchup. GAIN is not clamped to V
DD
. When CLK
is taken above V
DD
, it will be clamped by an internal diode. The CLK pin
can handle input currents of greater than 100mA above V
DD
without
latchup.
4
U W
MIN
4.75
2.7
– 5.25
TYP
MAX
5.25
5.25
– 4.75
UNITS
V
V
V
V
mA
mA
mW
0
48
1.4
250
58
2.5
300
UW
MIN
0.02
TYP
70
MAX
10
90
UNITS
MHz
ns
ns
ns
ns
ps
10
20
20
30
50
50
– 250
Note 5:
V
DD
= 5V, V
SS
= – 5V or 0V, f
SAMPLE
= 10MHz, t
r
= t
f
= 5ns unless
otherwise specified.
Note 6:
Dynamic specifications are guaranteed for dual supply operation
with a single-ended + A
IN
input and – A
IN
grounded. For single supply
dynamic specifications, refer to the Typical Performance Characteristics.
Note 7:
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 8:
Bipolar offset is the offset voltage measured from –0.5LSB
when the output code flickers between 0000 0000 0000 and
1111 1111 1111.
Note 9:
Guaranteed by design, not subject to test.
Note 10:
Recommended operating conditions.
LTC1420
TYPICAL PERFOR A CE CHARACTERISTICS
S/(N+D) vs Input Frequency
and Amplitude
75
V
IN
= 0dB
70
65
DUAL SUPPLIES
±2.048V
RANGE
GAIN = 1×
dBc
70
60
50
40
–50
DUAL SUPPLIES
±2.048V
RANGE
GAIN = 1×
f
IN
= 5MHz
–40
–30
–20
–10
INPUT AMPLITUDE (dBFS)
0
1420 G03
DISTORTION (dB)
S/(N + D) (dB)
V
IN
= –6dB
SFDR (dBc AND dBFS)
60
55
V
IN
= –20dB
50
0.1
10
1
INPUT FREQUENCY (MHz)
S/(N+D) vs Input Frequency
and Amplitude
75
V
IN
= 0dB
100
70
S/(N + D) (dB)
SINGLE SUPPLY
±1.024V
RANGE
GAIN = 2×
SFDR (dBc AND dBFS)
65
V
IN
= –6dB
80
dBc
70
60
50
SINGLE SUPPLY
±1.024V
RANGE
GAIN = 2×
f
IN
= 5MHz
–40
–30
–20
–10
INPUT AMPLITUDE (dBFS)
0
1420 G05
DISTORTION (dB)
60
55
V
IN
= –20dB
50
0.1
10
1
INPUT FREQUENCY (MHz)
100
1420 G02
SFDR vs Input Frequency,
Differential Input
–50
–55
–60
–65
SFDR (dB)
SFDR (dB)
–70
–75
–80
–85
–90
–95
–100
0.1
10
1
INPUT FREQUENCY (MHz)
100
1420 F07
DUAL SUPPLIES
±2.048V
RANGE
GAIN = 1×
A
IN
= 0dBFS
–75
–80
–85
–90
–95
HITS
U W
1420 G01
Spurious-Free Dynamic Range
vs Input Amplitude
100
90
80
dBFS
–50
–55
–60
–65
–70
–75
–80
–85
–90
–95
Distortion vs Input Frequency
DUAL SUPPLIES
±2.048V
RANGE
GAIN = 1×
A
IN
= 0dBFS
THD
3RD
2ND
100
0
1
10
INPUT FREQUENCY (MHz)
100
1420 G04
Spurious-Free Dynamic Range
vs Input Amplitude
–50
dBFS
90
Distortion vs Input Frequency
–55
–60
–65
–70
–75
–80
–85
–90
–95
0
1
10
INPUT FREQUENCY (MHz)
100
1420 G06
SINGLE SUPPLY
±1.024V
RANGE
GAIN = 2×
A
IN
= 0dBFS
THD
2ND
3RD
40
–50
SFDR vs Input Frequency,
Differential Input
–50
–55
–60
–65
–70
SINGLE SUPPLY
±1.024V
RANGE
GAIN = 2×
A
IN
= 0dBFS
Grounded Input Histogram
V
REF
= 4.096V
GAIN = 1×
410554
–100
0.1
10
1
INPUT FREQUENCY (MHz)
100
1420 F08
1570
N–1
N
CODE
1572
N+1
1420 F09
5
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