LTC1405
12-Bit, 5Msps,
Sampling ADC
FEATURES
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DESCRIPTIO
5Msps Sample Rate
Low Power Dissipation: 115mW
Single 5V Supply or
±5V
Supplies
71.3dB S/(N + D) and 85dB SFDR at Nyquist
100MHz Full-Power Bandwidth Sampling
Input PGA
Integral Nonlinearity Error <0.35LSB
Differential Nonlinearity <0.25LSB
±2.048V, ±1.024V
and
±0.512V
Bipolar Input Range
Out-of-Range Indicator
True Differential Inputs with 75dB CMRR
Pin-Compatible 10Msps Version (LTC1420)
28-Pin Narrow SSOP Package
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 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
71.3dB S/(N + D) and 85dB SFDR at the Nyquist input fre-
quency 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 sepa-
rate output logic supply allows direct connection to 3V
components.
APPLICATIO S
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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.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
5V
1µF
GAIN
V
DD
(PIN 7)
5V
1µF
V
DD
(PIN 23)
5V
1µF
OV
DD
OPTIONAL 3V
LOGIC SUPPLY
+
A
IN
S/H
–A
IN
V
CM
1µF
MODE SELECT
SENSE
PIPELINED 12-BIT ADC
OF
OUTPUT
BUFFERS
INL (LSBs)
D11 (MSB)
DIGITAL CORRECTION
LOGIC
2.5V
REFERENCE
D0 (LSB)
5MHz CLK
V
REF
1µF
2.048V
1405 TA01
V
SS
1µF
0V OR –5V
GND
(PIN 6)
GND
(PIN 8)
GND
(PIN 24)
OGND
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
1405 TA02
U
U
1405fa
1
LTC1405
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
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
D10 10
D9 11
D8 12
D7 13
D6 14
GN PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 80°C/W
Consult factory for parts specified with wider operating temperature ranges.
CO VERTER CHARACTERISTICS
PARAMETER
Resolution (No Missing Codes)
Integral Linearity Error
Differential Linearity Error
Offset Error
Full-Scale Error
Full-Scale Tempco
The
●
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)
CONDITIONS
●
MIN
12
●
●
TYP
±0.35
±0.25
±5
MAX
±1
±1
12
16
30
UNITS
Bits
LSB
LSB
LSB
LSB
LSB
ppm/°C
(Note 7)
(Note 8)
●
±10
I
OUT(REF)
= 0
±15
A ALOG I PUT
The
●
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)
PARAMETER
Analog Input Range (Note 9)
+A
IN
– (–A
IN
)
CONDITIONS
V
REF
= 4.096V (SENSE = 0V), GAIN = 5V
V
REF
= 4.096V (SENSE = 0V), GAIN = 0V
V
REF
= 2.048V (SENSE = V
REF
), GAIN = 5V
V
REF
= 2.048V (SENSE = V
REF
), GAIN = 0V
External V
REF
(SENSE = 5V), GAIN = 5V
External V
REF
(SENSE = 5V), GAIN = 0V
Between Conversions
During Conversions
●
●
●
●
●
●
●
SYMBOL
V
IN
MIN
TYP
±2.048
±1.024
±1.024
±0.512
±V
REF
/2
±V
REF
/4
MAX
UNITS
V
V
V
V
V
V
I
IN
C
IN
t
ACQ
Analog Input Leakage Current
Analog Input Capacitance
Sample-and-Hold Acquisition Time
±10
12
6
50
1405fa
2
U
µA
pF
pF
ns
W
U
U
W W
W
U
U
U
LTC1405
A ALOG I PUT
The
●
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)
PARAMETER
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
CONDITIONS
MIN
TYP
– 250
0.6
75
SYMBOL
t
AP
t
jitter
CMRR
MAX
UNITS
ps
ps
dB
The
●
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
S/(N + D)
THD
SFDR
IMD
PARAMETER
Signal-to-Noise Plus Distortion Ratio
Total Harmonic Distortion
Peak Harmonic or Spurious Noise
Intermodulation Distortion
Full-Power Bandwidth
Input Referred Noise
±2.048V
Input Range
±1.024V
Input Range, 2x Mode (SENSE = GAIN = 0V)
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
f
IN1
= 29.37kHz, f
IN2
= 32.446kHz
●
●
●
●
●
●
DY A IC ACCURACY
I TER AL REFERE CE 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
2.500
±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 AND OUTPUTS
SYMBOL
V
IH
V
IL
PARAMETER
High Level Input Voltage (Clock Pin)
Low Level Input Voltage (Clock Pin)
The
●
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
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
●
●
●
●
U
U
U
U
W U
U
U
MIN
69.0
68.7
TYP
71.6
71.3
– 87
– 83
– 89
– 85
– 80
100
0.22
0.33
MAX
UNITS
dB
dB
– 78.5
– 77.0
– 79.5
– 78.0
dB
dB
dB
dB
dB
MHz
LSB
RMS
LSB
RMS
U
MIN
2.4
3.5
TYP
MAX
UNITS
V
V
0.8
1
V
V
1405fa
3
LTC1405
temperature range, otherwise specifications are at T
A
= 25°C. Specifications are guaranteed for both dual supply and single supply
operation. (Note 5)
SYMBOL
I
IN
C
IN
V
OH
PARAMETER
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
●
●
●
●
DIGITAL I PUTS AND OUTPUTS
The
●
denotes the specifications which apply over the full operating
CONDITIONS
V
IN
= 0V to V
DD
●
V
OL
Low Level Output Voltage
I
SOURCE
I
SINK
Output Source Current
Output Sink Current
The
●
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
DD
V
SS
I
DD
I
SS
P
D
PARAMETER
Positive Supply Voltage
Negative Supply Voltage
Positive Supply Current
Negative Supply Current
Power Dissipation
CONDITIONS
(Note 10)
Dual Supply Mode
Single Supply Mode
●
●
●
POWER REQUIRE E TS
TI I G CHARACTERISTICS
SYMBOL
f
SAMPLE
t
CONV
t
ACQ
t
H
t
L
t
AD
PARAMETER
Sampling Frequency
Conversion Time
Acquisition Time
CLK High Time
CLK Low Time
Aperture Delay of Sample-and-Hold
The
●
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 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.
4
UW
U
U
MIN
TYP
1.8
MAX
±10
UNITS
µA
pF
V
V
V
V
4.0
2.3
4.74
4.71
2.6
0.05
0.10
0.05
0.10
50
35
0.4
0.4
V
V
V
V
mA
mA
MIN
4.75
– 5.25
TYP
MAX
5.25
– 4.75
UNITS
V
V
V
mA
mA
mW
0
23
0.8
115
28
1.2
145
UW
MIN
0.02
TYP
150
MAX
5
180
UNITS
MHz
ns
ns
ns
ns
ps
20
20
20
50
100
100
– 250
(Note 9)
(Note 9)
●
●
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.
1405fa
LTC1405
ELECTRICAL CHARACTERISTICS
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.
TYPICAL PERFORMANCE CHARACTERISTICS
S/(N+D) vs Input Frequency
and Amplitude
75
V
IN
= 0dB
70
S/(N + D) (dB)
80
dBc
70
60
50
40
–50
DUAL SUPPLIES
±2.048V
RANGE
GAIN = 1×
f
IN
= 2.5MHz
–40
–30
–20
–10
INPUT AMPLITUDE (dBFS)
0
1405 G02
65
DUAL SUPPLIES
±2.048V
RANGE
GAIN = 1×
DISTORTION (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
SINGLE SUPPLY
±1.024V
RANGE
GAIN = 2×
SFDR (dBc AND dBFS)
70
S/(N + D) (dB)
65
V
IN
= –6dB
80
dBc
70
60
50
SINGLE SUPPLY
±1.024V
RANGE
GAIN = 2×
f
IN
= 2.5MHz
–40
–30
–20
–10
INPUT AMPLITUDE (dBFS)
0
1405 G05
DISTORTION (dB)
60
55
V
IN
= –20dB
50
0.1
10
1
INPUT FREQUENCY (MHz)
100
1405 G04
U W
1405 G01
Spurious-Free Dynamic Range
vs Input Amplitude
100
90
–60
–65
–70
–75
–80
–85
–90
–95
–50
Distortion vs Input Frequency
–55
DUAL SUPPLIES
±2.048V
RANGE
GAIN = 1×
A
IN
= 0dBFS
dBFS
THD
3RD
2ND
100
0
1
10
INPUT FREQUENCY (MHz)
100
1405 G03
Spurious-Free Dynamic Range
vs Input Amplitude
100
dBFS
90
Distortion vs Input Frequency
–50
–55
–60
–65
–70
–75
–80
–85
–90
–95
0
1
10
INPUT FREQUENCY (MHz)
100
1405 G06
SINGLE SUPPLY
±1.024V
RANGE
GAIN = 2×
A
IN
= 0dBFS
THD
2ND
3RD
40
–50
1405fa
5
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