Final Electrical Specifications
LTC1405
12-Bit, 5Msps,
Sampling ADC
January 2000
FEATURES
s
s
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s
s
s
s
s
s
s
s
s
s
DESCRIPTIO
5Msps Sample Rate
Low Power Dissipation: 115mW
Single 5V Supply or
±5V
Supplies
Integral Nonlinearity Error <0.35LSB
Differential Nonlinearity <0.25LSB
71.3dB S/(N + D) and 85dB 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
28-Pin Narrow SSOP Package
Pin-Compatible 10Msps Version (LTC1420)
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.
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
GAIN
5V
1µF
AV
DD
5V
1µF
DV
DD
OV
DD
OPTIONAL 3V
LOGIC SUPPLY
1.00
0.75
0.50
INL (LSBs)
+
A
IN
S/H
–A
IN
V
CM
1µF
MODE SELECT
SENSE
PIPELINED 12-BIT ADC
OF
D11 (MSB)
OUTPUT
BUFFERS
DIGITAL CORRECTION
LOGIC
2.5V
REFERENCE
D0 (LSB)
–1.00
5MHz CLK
V
REF
1µF
2.048V
1405 TA01
V
SS
1µF
0V OR –5V
AGND
DGND
OGND
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.
U
Typical INL Curve
0.25
0
–0.25
–0.50
–0.75
0
1024
2048
CODE
3072
4096
1405 TA02
U
U
1
LTC1405
ABSOLUTE
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
+A
IN
–A
IN
V
CM
SENSE
V
REF
AGND
AV
DD
AGND
D11 (MSB)
1
2
3
4
5
6
7
8
9
28 GAIN
27 OF
26 CLK
25 V
SS
24 DGND
23 DV
DD
22 OV
DD
21 OGND
20 D0
19 D1
18 D2
17 D3
16 D4
15 D5
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
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.
CO VERTER 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
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)
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
q
q
q
q
q
q
q
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
2
U
µA
pF
pF
ns
W
U
U
W W
W
U
U
U
LTC1405
A ALOG I PUT
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)
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
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
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
q
q
q
q
q
q
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
Low Level Input Voltage
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
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
q
q
q
q
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
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
q
q
q
q
DIGITAL I PUTS AND OUTPUTS
The
q
denotes the specifications which apply over the full operating
CONDITIONS
V
IN
= 0V to V
DD
q
V
OL
Low Level Output Voltage
I
SOURCE
I
SINK
Output Source Current
Output Sink Current
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
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
q
q
q
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
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
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)
q
q
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.
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.
PI FU CTIO S
+ 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 1µF to 10µF 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 1µF to
10µF ceramic.
GND (Pin 6):
DAC Reference Ground.
V
DD
(Pin 7):
Analog 5V Supply. Bypass to GND with a 1µF
to 10µF 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 1µF ceramic.
V
DD
(Pin 23):
Analog 5V Supply. Bypass to GND with a 1µF
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 1µF 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.
U
U
U
5
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