1
LTC1605
16-Bit, 100ksps,
Sampling ADC
DESCRIPTIO
N
U
FEATURES
The LTC
1605 is a 100ksps, sampling 16-bit A/D con-
verter that draws only 55mW (typical) from a single 5V
supply. This easy-to-use device includes sample-and-
hold, precision reference, switched capacitor successive
approximation A/D and trimmed internal clock.
The LTC1605's input range is an industry standard
10V.
Maximum DC specs include
2.0LSB INL and 16-bits no
missing codes over temperature. An external reference
can be used if greater accuracy over temperature is
needed.
The ADC has a microprocessor compatible, 16-bit or two
byte parallel output port. A convert start input and a data
ready signal (BUSY) ease connections to FIFOs, DSPs and
microprocessors.
s
Sample Rate: 100ksps
s
Single 5V Supply
s
Bipolar Input Range:
10V
s
Power Dissipation: 55mW Typ
s
Integral Nonlinearity:
2.0LSB Max
s
Guaranteed No Missing Codes
s
Signal-to-Noise Ratio: 86dB Typ
s
Operates with Internal or External Reference
s
Internal Synchronized Clock
s
28-Pin 0.3" PDIP, SSOP and SW Packages
s
Improved 2nd Source to ADS7805 and AD976
s
Industrial Process Control
s
Multiplexed Data Acquisition Systems
s
High Speed Data Acquisition for PCs
s
Digital Signal Processing
APPLICATIO
N
S
U
TYPICAL APPLICATIO
N
U
Low Power, 100kHz, 16-Bit Sampling ADC on 5V Supply
4k
20k
20k
200
REFERENCE
4k
10k
16-BIT
SAMPLING ADC
D15 TO D0
33.2k
2.2
F
10
F
0.1
F
2.2
F
10V
INPUT
V
IN
CAP
REF
AGND1
1
4
3
2
AGND2
5
DGND
14
CONTROL
LOGIC AND
TIMING
BUSY
BYTE
CS
R/C
28
27
6 TO 13
15 TO 22
26
25
24
23
DIGITAL
CONTROL
SIGNALS
1605 TA01
16-BIT
OR 2 BYTE
PARALLEL
BUS
5V
V
DIG
V
ANA
BUFFER
Typical INL Curve
CODE
0
INL (LSBs)
65535
1605 TA02
16384
32768
49152
2.0
1.5
1.0
0.5
0
0.5
1.0
1.5
2.0
, LTC and LT are registered trademarks of Linear Technology Corporation.
2
LTC1605
A
U
G
W
A
W
U
W
A
R
BSOLUTE
XI
TI
S
W
U
U
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
(Notes 1, 2)
V
ANA
.......................................................................... 7V
V
DIG
to V
ANA
........................................................... 0.3V
V
DIG
........................................................................... 7V
Ground Voltage Difference
DGND, AGND1 and AGND2 ..............................
0.3V
Analog Inputs (Note 3)
V
IN
.....................................................................
25V
CAP ............................ V
ANA
+ 0.3V to AGND2 0.3V
REF .................................... Indefinite Short to AGND2
Momentary Short to V
ANA
Digital Input Voltage (Note 4) ............ V
SS
0.3V to 10V
Digital Output Voltage ........ V
DGND
0.3V to V
DIG
+ 0.3V
Power Dissipation .............................................. 500mW
Operating Ambient Temperature Range
LTC1605C................................................ 0
C to 70
C
LTC1605I ............................................ 40
C to 85
C
Storage Temperature Range ................. 65
C to 150
C
Lead Temperature (Soldering, 10 sec).................. 300
C
LTC1605ACG
LTC1605ACN
LTC1605ACSW
LTC1605AIG
LTC1605AIN
LTC1605AISW
LTC1605CG
LTC1605CN
LTC1605CSW
LTC1605IG
LTC1605IN
LTC1605ISW
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
IN
AGND1
REF
CAP
AGND2
D15 (MSB)
D14
D13
D12
D11
D10
D9
D8
DGND
V
DIG
V
ANA
BUSY
CS
R/C
BYTE
D0
D1
D2
D3
D4
D5
D6
D7
G PACKAGE
28-LEAD PLASTIC SSOP
SW PACKAGE
28-LEAD PLASTIC SO WIDE
N PACKAGE
28-LEAD PDIP
TOP VIEW
T
JMAX
= 125
C,
JA
= 95
C/W (G)
T
JMAX
= 125
C,
JA
= 130
C/W (N)
T
JMAX
= 125
C,
JA
= 130
C/W (SW)
Consult factory for Military grade parts.
CO
N
VERTER CHARACTERISTICS
U
With external reference (Notes 5, 6).
LTC1605
LTC1605A
PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
Resolution
q
16
16
Bits
No Missing Codes
q
15
16
Bits
Transition Noise
1.0
1.0
LSB
Integral Linearity Error
(Note 7)
q
3
2
LSB
Bipolar Zero Error
Ext. Reference = 2.5V (Note 8)
q
10
10
mV
Bipolar Zero Error Drift
2
2
ppm/
C
Full-Scale Error Drift
7
5
ppm/
C
Full-Scale Error
Ext. Reference = 2.5V (Notes 12, 13)
q
0.50
0.25
%
Full-Scale Error Drift
Ext. Reference = 2.5V
2
2
ppm/
C
Power Supply Sensitivity
V
ANA
= V
DIG
= V
DD
V
DD
= 5V
5% (Note 9)
8
8
LSB
3
LTC1605
LTC1605/LTC1605A
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IN
Analog Input Range (Note 9)
4.75V
V
ANA
5.25V, 4.75V
V
DIG
5.25V
q
10
V
I
IN
Analog Input Leakage Current
CS = High
q
1
A
C
IN
Analog Input Capacitance
10
pF
R
IN
Analog Input Impedance
20
k
A
N
ALOG I
N
PUT
U
U
(Note 5)
DY
N
A
M
IC ACCURACY
U
W
(Notes 5, 14)
LTC1605/LTC1605A
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
S/(N + D)
Signal-to-(Noise + Distortion) Ratio
1kHz Input Signal (Note 14)
87.5
dB
10kHz Input Signal
87
dB
20kHz, 60dB Input Signal
30
dB
THD
Total Harmonic Distortion
1kHz Input Signal, First 5 Harmonics
102
dB
10kHz Input Signal, First 5 Harmonics
94
dB
Peak Harmonic or Spurious Noise
1kHz Input Signal
102
dB
10kHz Input Signal
94
dB
Full-Power Bandwidth
(Note 15)
275
kHz
Aperture Delay
40
ns
Aperture Jitter
Sufficient to Meet AC Specs
Transient Response
Full-Scale Step (Note 9)
2
s
Overvoltage Recovery
(Note 16)
150
ns
I
N
TER
N
AL REFERE
N
CE CHARACTERISTICS
U
U
U
LTC1605/LTC1605A
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
REF
Output Voltage
I
OUT
= 0
q
2.470
2.500
2.520
V
V
REF
Output Tempco
I
OUT
= 0
5
ppm/
C
Internal Reference Source Current
1
A
External Reference Voltage for Specified Linearity
(Notes 9, 10)
2.30
2.50
2.70
V
External Reference Current Drain
Ext. Reference = 2.5V (Note 9)
q
100
A
CAP Output Voltage
I
OUT
= 0
2.50
V
DIGITAL I
N
PUTS A
N
D DIGITAL OUTPUTS
U
U
LTC1605/LTC1605A
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IH
High Level Input Voltage
V
DD
= 5.25V
q
2.4
V
V
IL
Low Level Input Voltage
V
DD
= 4.75V
q
0.8
V
I
IN
Digital Input Current
V
IN
= 0V to V
DD
q
10
A
C
IN
Digital Input Capacitance
5
pF
V
OH
High Level Output Voltage
V
DD
= 4.75V
I
O
= 10
A
4.5
V
I
O
= 200
A
q
4.0
V
V
OL
Low Level Output Voltage
V
DD
= 4.75V
I
O
= 160
A
0.05
V
I
O
= 1.6mA
q
0.10
0.4
V
(Note 5)
(Note 5)
4
LTC1605
DIGITAL I
N
PUTS A
N
D DIGITAL OUTPUTS
U
U
(Note 5)
LTC1605/LTC1605A
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
I
OZ
Hi-Z Output Leakage D15 to D0
V
OUT
= 0V to V
DD
, CS High
q
10
A
C
OZ
Hi-Z Output Capacitance D15 to D0
CS High (Note 9)
q
15
pF
I
SOURCE
Output Source Current
V
OUT
= 0V
10
mA
I
SINK
Output Sink Current
V
OUT
= V
DD
10
mA
(Note 5)
LTC1605/LTC1605A
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
f
SAMPLE(MAX)
Maximum Sampling Frequency
q
100
kHz
t
CONV
Conversion Time
q
8
s
t
ACQ
Acquisition Time
q
2
s
t
1
Convert Pulse Width
(Note 11)
q
40
ns
t
2
Data Valid Delay After R/C
(Note 9)
q
8
s
t
3
BUSY Delay from R/C
C
L
= 50pF
q
65
ns
t
4
BUSY Low
8
s
t
5
BUSY Delay After End of Conversion
220
ns
t
6
Aperture Delay
40
ns
t
7
Bus Relinquish Time
q
10
35
83
ns
t
8
BUSY Delay After Data Valid
q
50
200
ns
t
9
Previous Data Valid After R/C
7.4
s
t
10
R/C to CS Setup Time
(Notes 9, 10)
10
ns
t
11
Time Between Conversions
10
s
t
12
Bus Access and Byte Delay
(Notes 9, 10)
10
83
ns
TI
M
I
N
G CHARACTERISTICS
W
U
POWER REQUIRE
M
E
N
TS
W
U
(Note 5)
LTC1605/LTC1605A
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
DD
Positive Supply Voltage
(Notes 9, 10)
4.75
5.25
V
I
DD
Positive Supply Current
q
11
16
mA
P
DIS
Power Dissipation
55
80
mW
The
q
indicates specifications which apply over the full operating
temperature range; all other limits and typicals T
A
= 25
C.
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 DGND, AGND1
and AGND2 wired together (unless otherwise noted).
Note 3: When these pin voltages are taken below ground or above V
ANA
=
V
DIG
= V
DD
, they will be clamped by internal diodes. This product can
handle input currents of greater than 100mA below ground or above V
DD
without latch-up.
Note 4: When these pin voltages are taken below ground, they will be
clamped by internal diodes. This product can handle input currents of
90mA below ground without latchup. These pins are not clamped to V
DD
.
Note 5: V
DD
= 5V, f
SAMPLE
= 100kHz, t
r
= t
f
= 5ns unless otherwise
specified.
Note 6: Linearity, offset and full-scale specifications apply for a V
IN
input
with respect to ground.
Note 7: Integral nonlinearity is defined as the deviation of a code from a
straight line passing through the actual end points 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 0.5 LSB when
the output code flickers between 0000 0000 0000 0000 and 1111 1111
1111 1111.
Note 9: Guaranteed by design, not subject to test.
Note 10: Recommended operating conditions.
5
LTC1605
Note 11: With CS low the falling R/C edge starts a conversion. If R/C
returns high at a critical point during the conversion it can create small
errors. For best results ensure that R/C returns high within 3
s after the
start of the conversion.
Note 12: As measured with fixed resistors shown in Figure 4. Adjustable to
zero with external potentiometer.
Note 13: Full-scale error is the worst-case of FS or +FS untrimmed
deviation from ideal first and last code transitions, divided by the transition
voltage (not divided by the full-scale range) and includes the effect of
offset error.
Note 14: All specifications in dB are referred to a full-scale
10V input.
Note 15: Full-power bandwidth is defined as full-scale input frequency at
which a signal-to-(noise + distortion) degrades to 60dB or 10 bits of
accuracy.
Note 16: Recovers to specified performance after (2
FS) input
overvoltage.
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
Supply Current vs Supply Voltage
Change in CAP Voltage vs
Load Current
SUPPLY VOLTAGE (V)
4.50
9.5
SUPPLY CURRENT (mA)
10.0
10.5
11.0
11.5
12.0
12.5
4.75
5.00
5.25
5.50
1605 TPC01
f
SAMPLE
= 100kHz
LOAD CURRENT (mA)
CHANGE IN CAP VOLTAGE (V)
0.05
0.04
0.03
0.02
0.01
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
60
40
20
0
1605 TPC03
70
80
50
30
10
10
TEMPERATURE (
C)
50
10.0
POSITIVE SUPPLY CURRENT (mA)
10.5
11.0
11.5
12.0
25
0
25
50
1605 TPC02
75
100
f
SAMPLE
= 100kHz
Supply Current vs Temperature
ELECTRICAL CHARACTERISTICS
Typical INL Curve
CODE
0
INL (LSBs)
65535
1605 TPC04
16384
32768
49152
2.0
1.5
1.0
0.5
0
0.5
1.0
1.5
2.0
CODE
0
DNL (LSBs)
65535
1605 TPC05
16384
32768
49152
2.0
1.5
1.0
0.5
0
0.5
1.0
1.5
2.0
Power Supply Feedthrough vs
Ripple Frequency
Typical DNL Curve
RIPPLE FREQUENCY (Hz)
70
60
50
40
30
20
POWER SUPPLY FEEDTHROUGH (dB)
1M
1605 TPC06
1
100
10
1k
100k
10k
PDF 
ZIP