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LTC1405
Final Electrical Specifications
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However,
no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the
interconnection of its circuits as described herein will not infringe on existing patent rights.
12-Bit, 5Msps,
Sampling ADC
January 2000
The LTC
1405 is a 5Msps, 12-bit sampling A/D converter
that draws only 115mW 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 LTC1405 has a flexible input circuit that allows full-
scale input ranges of
2.048V,
1.024V and
0.512V. The
input common mode range is rail-to-rail and a common
mode bias voltage is provided for single supply applica-
tions. 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
71.3dB S/(N + D) and 85dB SFDR at the Nyquist input
frequency of 2.5MHz.
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.
DESCRIPTIO
U
s
5Msps Sample Rate
s
Low Power Dissipation: 115mW
s
Single 5V Supply or
5V Supplies
s
Integral Nonlinearity Error <0.35LSB
s
Differential Nonlinearity <0.25LSB
s
71.3dB S/(N + D) and 85dB SFDR at Nyquist
s
100MHz Full-Power Bandwidth Sampling
s
2.048V,
1.024V and
0.512V Bipolar Input Range
s
Input PGA
s
Out-of-Range Indicator
s
True Differential Inputs with 75dB CMRR
s
28-Pin Narrow SSOP Package
s
Pin-Compatible 10Msps Version (LTC1420)
FEATURES
TYPICAL APPLICATIO
U
s
Telecommunications
s
Digital Signal Processing
s
Multiplexed Data Acquisition Systems
s
High Speed Data Acquisition
s
Spectral Analysis
s
Imaging Systems
APPLICATIO S
U
, LTC and LT are registered trademarks of Linear Technology Corporation.
Typical INL Curve
CODE
0
1024
2048
3072
4096
INL (LSBs)
1405 TA02
1.00
0.75
0.50
0.25
0
0.25
0.50
0.75
1.00
DIGITAL CORRECTION
LOGIC
OUTPUT
BUFFERS
1405 TA01
MODE SELECT
S/H
5V
1
F
1
F
0V OR 5V
1
F
1
F
V
CM
GAIN
5V
AV
DD
1
F
5V
DV
DD
1
F
OV
DD
OGND
OPTIONAL 3V
LOGIC SUPPLY
OF
D11 (MSB)
D0 (LSB)
5MHz CLK
SENSE
V
REF
A
IN
+
A
IN
DGND
V
SS
AGND
2.048V
2.5V
REFERENCE
PIPELINED 12-BIT ADC
2
LTC1405
ABSOLUTE AXI U
RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
AV
DD
= DV
DD
= 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
LTC1405C ............................................... 0
C to 70
C
LTC1405I ............................................ 40
C to 85
C
Storage Temperature Range ................. 65
C to 150
C
Lead Temperature (Soldering, 10 sec).................. 300
C
ORDER PART
NUMBER
LTC1405CGN
LTC1405IGN
CO VERTER CHARACTERISTICS
U
Consult factory for Military grade parts.
T
JMAX
= 110
C,
JA
= 110
C/W
1
2
3
4
5
6
7
8
9
10
11
12
13
14
TOP VIEW
GN PACKAGE
28-LEAD PLASTIC SSOP
28
27
26
25
24
23
22
21
20
19
18
17
16
15
+A
IN
A
IN
V
CM
SENSE
V
REF
AGND
AV
DD
AGND
D11 (MSB)
D10
D9
D8
D7
D6
GAIN
OF
CLK
V
SS
DGND
DV
DD
OV
DD
OGND
D0
D1
D2
D3
D4
D5
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
CONDITIONS
MIN
TYP
MAX
UNITS
Resolution (No Missing Codes)
q
12
Bits
Integral Linearity Error
(Note 7)
q
0.35
1
LSB
Differential Linearity Error
q
0.25
1
LSB
Offset Error
(Note 8)
5
12
LSB
q
16
LSB
Full-Scale Error
10
30
LSB
Full-Scale Tempco
I
OUT(REF)
= 0
15
ppm/
C
PUT
U
I
A
A
U
LOG
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
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IN
Analog Input Range (Note 9)
V
REF
= 4.096V (SENSE = 0V), GAIN = 5V
q
2.048
V
+A
IN
(A
IN
)
V
REF
= 4.096V (SENSE = 0V), GAIN = 0V
q
1.024
V
V
REF
= 2.048V (SENSE = V
REF
), GAIN = 5V
q
1.024
V
V
REF
= 2.048V (SENSE = V
REF
), GAIN = 0V
q
0.512
V
External V
REF
(SENSE = 5V), GAIN = 5V
q
V
REF
/2
V
External V
REF
(SENSE = 5V), GAIN = 0V
q
V
REF
/4
V
I
IN
Analog Input Leakage Current
q
10
A
C
IN
Analog Input Capacitance
Between Conversions
12
pF
During Conversions
6
pF
t
ACQ
Sample-and-Hold Acquisition Time
50
ns
3
LTC1405
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IH
High Level Input Voltage
V
DD
= 5.25V, V
SS
= 0V
q
2.4
V
V
DD
= 5.25V, V
SS
= 5V
q
3.5
V
V
IL
Low Level Input Voltage
V
DD
= 4.75V, V
SS
= 0V
q
0.8
V
V
DD
= 4.75V, V
SS
= 5V
q
1
V
I TER AL REFERE CE CHARACTERISTICS
U
U
U
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
CM
Output Voltage
I
OUT
= 0
2.475
2.500
2.525
V
V
CM
Output Tempco
I
OUT
= 0
15
ppm/
C
V
CM
Line Regulation
4.75V
V
DD
5.25V
0.6
mV/V
5.25V
V
SS
4.75V
0.03
mV/V
V
CM
Output Resistance
0.1mA
I
OUT
0.1mA
8
V
REF
Output Voltage
SENSE = GND, I
OUT
= 0
4.096
V
SENSE = V
REF
, I
OUT
= 0
2.048
V
SENSE = V
DD
Drive V
REF
with
V
External Reference
V
REF
Output Tempco
15
ppm/
C
T
A
= 25
C. Specifications are guaranteed for both dual supply and single supply operation. (Note 5)
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)
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
= 5MHz, V
REF
= 4.096V. + A
IN
= 0.1dBFS single ended input,
A
IN
= 0V. (Note 6)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
S/(N + D)
Signal-to-Noise Plus Distortion Ratio
1MHz Input Signal
q
69.0
71.6
dB
2.5MHz Input Signal
q
68.7
71.3
dB
THD
Total Harmonic Distortion
1MHz Input Signal, First 5 Harmonics
q
87
78.5
dB
2.5MHz Input Signal, First 5 Harmonics
q
83
77.0
dB
SFDR
Peak Harmonic or Spurious Noise
1MHz Input Signal
q
89
79.5
dB
2.5MHz Input Signal
q
85
78.0
dB
IMD
Intermodulation Distortion
f
IN1
= 29.37kHz, f
IN2
= 32.446kHz
80
dB
Full-Power Bandwidth
100
MHz
Input Referred Noise
2.048V Input Range
0.22
LSB
RMS
1.024V Input Range, 2x Mode (SENSE = GAIN = 0V)
0.33
LSB
RMS
ACCURACY
IC
DY
U
W
A
PUT
U
I
A
A
U
LOG
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
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
t
AP
Sample-and-Hold Aperture Delay Time
250
ps
t
jitter
Sample-and-Hold Aperture Delay Time Jitter
0.6
ps
CMRR
Analog Input Common Mode Rejection Ratio
2.048V < (A
IN
= +A
IN
) < 2.048V
75
dB
DIGITAL I PUTS A
N
D OUTPUTS
U
U
4
LTC1405
DIGITAL I PUTS A
N
D OUTPUTS
U
U
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
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
POWER REQUIRE E TS
W
U
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
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
DD
Positive Supply Voltage
(Note 10)
4.75
5.25
V
V
SS
Negative Supply Voltage
Dual Supply Mode
5.25
4.75
V
Single Supply Mode
0
V
I
DD
Positive Supply Current
q
23
28
mA
I
SS
Negative Supply Current
q
0.8
1.2
mA
P
D
Power Dissipation
q
115
145
mW
TI I G CHARACTERISTICS
W U
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
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
f
SAMPLE
Sampling Frequency
q
0.02
5
MHz
t
CONV
Conversion Time
q
150
180
ns
t
ACQ
Acquisition Time
q
20
50
ns
t
H
CLK High Time
(Note 9)
q
20
100
ns
t
L
CLK Low Time
(Note 9)
q
20
100
ns
t
AD
Aperture Delay of Sample-and-Hold
250
ps
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.
Note 5: V
DD
= 5V, V
SS
= 5V or 0V, f
SAMPLE
= 5MHz, t
r
= t
f
= 5ns unless
otherwise specified.
I
IN
Digital Input Current
V
IN
= 0V to V
DD
q
10
A
C
IN
Digital Input Capacitance
1.8
pF
V
OH
High Level Output Voltage
0V
DD
= 4.75V, I
O
= 10
A
4.74
V
0V
DD
= 4.75V, I
O
= 200
A
q
4.0
4.71
V
0V
DD
= 2.7V, I
O
= 10
A
2.6
V
0V
DD
= 2.7V, I
O
= 200
A
q
2.3
V
V
OL
Low Level Output Voltage
0V
DD
= 4.75V, I
O
= 160
A
0.05
V
0V
DD
= 4.75V, I
O
= 1.6mA
q
0.10
0.4
V
0V
DD
= 2.7V, I
O
= 160
A
0.05
V
0V
DD
= 2.7V, I
O
= 1.6mA
q
0.10
0.4
V
I
SOURCE
Output Source Current
V
OUT
= 0V
50
mA
I
SINK
Output Sink Current
V
OUT
= V
DD
35
mA
5
LTC1405
PI FU CTIO S
U
U
U
+ A
IN
(Pin 1): Positive Analog Input.
A
IN
(Pin 2): Negative Analog Input.
V
CM
(Pin 3): 2.5V Reference Output.Optional input com-
mon mode for single supply operation. Bypass to GND
with a 1
F to 10
F ceramic.
SENSE (Pin 4): Reference Programming Pin. Ground
selects V
REF
= 4.096V. Short to V
REF
for 2.048V. Connect
SENSE to V
DD
to drive V
REF
with an external reference.
V
REF
(Pin 5): DAC Reference. Bypass to GND with a 1
F to
10
F ceramic.
GND (Pin 6): DAC Reference Ground.
V
DD
(Pin 7): Analog 5V Supply. Bypass to GND with a 1
F
to 10
F ceramic.
GND (Pin 8): Analog Power Ground.
D11 to D0 (Pins 9 to 20): Data Outputs. The output format
is two's complement.
OGND (Pin 21): Output Logic Ground. Tie to GND.
OV
DD
(Pin 22): Positive Supply for the Output Logic.
Connect to Pin 23 for 5V logic. If not shorted to Pin 23,
bypass to GND with a 1
F ceramic.
V
DD
(Pin 23): Analog 5V Supply. Bypass to GND with a 1
F
ceramic.
GND (Pin 24): Analog Power Ground.
V
SS
(Pin 25): Negative Supply. Can be 5V or 0V. If V
SS
is
not shorted to GND, bypass to GND with a 1
F ceramic.
CLK (Pin 26): Conversion Start Signal. This active high
signal starts a conversion on its rising edge.
OF (Pin 27): Overflow Output. This signal is high when the
digital output is 011111111111 or 100000000000.
GAIN (Pin 28): Gain Select for Input PGA. 5V selects an
input gain of 1, 0V selects a gain of 2.
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.
ELECTRICAL CHARACTERISTICS
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