LTC1605
16-Bit, 100ksps,
Sampling ADC
FEATURES
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DESCRIPTION
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Sample Rate: 100ksps
Single 5V Supply
Bipolar Input Range:
±
10V
Power Dissipation: 55mW Typ
Integral Nonlinearity:
±2.0LSB
Max
Guaranteed No Missing Codes
Signal-to-Noise Ratio: 86dB Typ
Operates with Internal or External Reference
Internal Synchronized Clock
28-Pin 0.3” PDIP, SSOP and SW Packages
Improved 2nd Source to ADS7805 and AD976
APPLICATIONS
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Industrial Process Control
Multiplexed Data Acquisition Systems
High Speed Data Acquisition for PCs
Digital Signal Processing
TYPICAL APPLICATION
Low Power, 100kHz, 16-Bit Sampling ADC on 5V Supply
5V
10µF
28
27
V
DIG
V
ANA
±10V
200Ω
INPUT
33.2k
4 CAP
BUSY 26
2.2µF
BUFFER
3 REF
2.2µF
AGND1
2
AGND2
5
DGND
14
1605 • TA01
0.1µF
1 V
IN
20k
16-BIT
SAMPLING ADC
4k
10k
D15 TO D0
16-BIT
OR 2 BYTE
PARALLEL
BUS
INL (LSBs)
6 TO 13
15 TO 22
4k
REFERENCE
CONTROL
LOGIC AND
TIMING
CS 25
R/C 24
BYTE 23
DIGITAL
CONTROL
SIGNALS
U
U
U
Typical INL Curve
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0
16384
32768
CODE
1605 • TA02
49152
65535
1
LTC1605
ABSOLUTE
(Notes 1, 2)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V
IN
1
AGND1 2
REF 3
CAP 4
AGND2 5
D15 (MSB) 6
D14 7
D13 8
D12 9
D11 10
D10 11
D9 12
D8 13
DGND 14
28 V
DIG
27 V
ANA
26 BUSY
25 CS
24 R/C
23 BYTE
22 D0
21 D1
20 D2
19 D3
18 D4
17 D5
16 D6
15 D7
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
ORDER PART
NUMBER
LTC1605ACG
LTC1605ACN
LTC1605ACSW
LTC1605AIG
LTC1605AIN
LTC1605AISW
LTC1605CG
LTC1605CN
LTC1605CSW
LTC1605IG
LTC1605IN
LTC1605ISW
G PACKAGE
28-LEAD PLASTIC SSOP
N PACKAGE
28-LEAD PDIP
SW PACKAGE
28-LEAD PLASTIC SO WIDE
T
JMAX
= 125°C,
θ
JA
= 95°C/W (G)
T
JMAX
= 125°C,
θ
JA
= 130°C/W (N)
T
JMAX
= 125°C,
θ
JA
= 130°C/W (SW)
Consult factory for Military grade parts.
CONVERTER CHARACTERISTICS
PARAMETER
Resolution
No Missing Codes
Transition Noise
Integral Linearity Error
Bipolar Zero Error
Bipolar Zero Error Drift
Full-Scale Error Drift
Full-Scale Error
Full-Scale Error Drift
Power Supply Sensitivity
V
ANA
= V
DIG
= V
DD
Ext. Reference = 2.5V (Notes 12, 13)
Ext. Reference = 2.5V
V
DD
= 5V
±5%
(Note 9)
(Note 7)
Ext. Reference = 2.5V (Note 8)
CONDITIONS
With external reference (Notes 5, 6).
MIN
q
q
LTC1605
TYP
MAX
MIN
16
16
LTC1605A
TYP
MAX
UNITS
Bits
Bits
16
15
1.0
±3
±10
±2
±7
1.0
±2
±10
±2
±5
±0.50
±0.25
±2
±8
±8
q
q
ppm/°C
ppm/°C
%
ppm/°C
LSB
q
±2
2
U
LSB
LSB
mV
W
U
U
W W
W
U
LTC1605
ANALOG INPUT
SYMBOL
V
IN
I
IN
C
IN
R
IN
PARAMETER
Analog Input Range (Note 9)
Analog Input Leakage Current
Analog Input Capacitance
Analog Input Impedance
DYNAMIC ACCURACY
SYMBOL
S/(N + D)
PARAMETER
Signal-to-(Noise + Distortion) Ratio
THD
Total Harmonic Distortion
Peak Harmonic or Spurious Noise
Full-Power Bandwidth
Aperture Delay
Aperture Jitter
Transient Response
Overvoltage Recovery
INTERNAL REFERENCE CHARACTERISTICS
PARAMETER
V
REF
Output Voltage
V
REF
Output Tempco
Internal Reference Source Current
External Reference Voltage for Specified Linearity
External Reference Current Drain
CAP Output Voltage
(Notes 9, 10)
Ext. Reference = 2.5V (Note 9)
I
OUT
= 0
CONDITIONS
I
OUT
= 0
I
OUT
= 0
DIGITAL INPUTS AND DIGITAL OUTPUTS
SYMBOL
V
IH
V
IL
I
IN
C
IN
V
OH
V
OL
PARAMETER
High Level Input Voltage
Low Level Input Voltage
Digital Input Current
Digital Input Capacitance
High Level Output Voltage
Low Level Output Voltage
V
DD
= 4.75V
V
DD
= 4.75V
CONDITIONS
V
DD
= 5.25V
V
DD
= 4.75V
V
IN
= 0V to V
DD
U
U
U
U
W U
U
U
(Note 5)
CONDITIONS
4.75V
≤
V
ANA
≤
5.25V, 4.75V
≤
V
DIG
≤
5.25V
CS = High
q
q
LTC1605/LTC1605A
MIN
TYP
MAX
±10
±1
10
20
UNITS
V
µA
pF
kΩ
(Notes 5, 14)
CONDITIONS
1kHz Input Signal (Note 14)
10kHz Input Signal
20kHz, – 60dB Input Signal
1kHz Input Signal, First 5 Harmonics
10kHz Input Signal, First 5 Harmonics
1kHz Input Signal
10kHz Input Signal
(Note 15)
LTC1605/LTC1605A
MIN
TYP
MAX
87.5
87
30
– 102
– 94
– 102
– 94
275
40
Sufficient to Meet AC Specs
Full-Scale Step (Note 9)
(Note 16)
150
2
µs
ns
UNITS
dB
dB
dB
dB
dB
dB
dB
kHz
ns
U
(Note 5)
LTC1605/LTC1605A
MIN
TYP
MAX
q
UNITS
V
ppm/°C
µA
2.470
2.500
±5
1
2.520
2.30
q
2.50
2.50
2.70
100
V
µA
V
(Note 5)
LTC1605/LTC1605A
MIN
TYP
MAX
q
q
q
UNITS
V
V
µA
pF
V
V
V
2.4
0.8
±10
5
4.5
I
O
= –10µA
I
O
= – 200µA
I
O
= 160µA
I
O
= 1.6mA
q
q
4.0
0.05
0.10
0.4
V
3
LTC1605
DIGITAL INPUTS AND DIGITAL OUTPUTS
SYMBOL
I
OZ
C
OZ
I
SOURCE
I
SINK
PARAMETER
Hi-Z Output Leakage D15 to D0
Hi-Z Output Capacitance D15 to D0
Output Source Current
Output Sink Current
CONDITIONS
V
OUT
= 0V to V
DD
, CS High
CS High (Note 9)
V
OUT
= 0V
V
OUT
= V
DD
TIMING CHARACTERISTICS
SYMBOL
f
SAMPLE(MAX)
t
CONV
t
ACQ
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
t
10
t
11
t
12
PARAMETER
Maximum Sampling Frequency
Conversion Time
Acquisition Time
Convert Pulse Width
Data Valid Delay After R/C↓
BUSY Delay from R/C↓
BUSY Low
BUSY Delay After End of Conversion
Aperture Delay
Bus Relinquish Time
BUSY Delay After Data Valid
Previous Data Valid After R/C↓
R/C to CS Setup Time
Time Between Conversions
Bus Access and Byte Delay
POWER REQUIREMENTS
SYMBOL
V
DD
I
DD
P
DIS
PARAMETER
Positive Supply Voltage
Positive Supply Current
Power Dissipation
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
.
4
U W
U
U
(Note 5)
LTC1605/LTC1605A
MIN
TYP
MAX
q
q
UNITS
µA
pF
mA
mA
±10
15
–10
10
UW
(Note 5)
LTC1605/LTC1605A
MIN
TYP
MAX
q
q
q
CONDITIONS
UNITS
kHz
µs
µs
ns
µs
ns
µs
ns
ns
100
8
2
40
8
65
8
220
40
(Note 11)
(Note 9)
C
L
= 50pF
q
q
q
q
q
10
50
10
10
10
35
200
7.4
83
ns
ns
µs
ns
µs
(Notes 9, 10)
(Notes 9, 10)
83
ns
(Note 5)
CONDITIONS
(Notes 9, 10)
q
LTC1605/LTC1605A
MIN
TYP
MAX
4.75
11
55
5.25
16
80
UNITS
V
mA
mW
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.
LTC1605
ELECTRICAL CHARACTERISTICS
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 3µs 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 PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
12.5
f
SAMPLE
= 100kHz
12.0
SUPPLY CURRENT (mA)
POSITIVE SUPPLY CURRENT (mA)
11.5
11.5
11.0
10.5
10.0
9.5
4.50
11.0
10.5
4.75
5.00
5.25
5.50
1605 • TPC01
10.0
–50
CHANGE IN CAP VOLTAGE (V)
SUPPLY VOLTAGE (V)
Typical INL Curve
2.0
1.5
1.0
2.0
1.5
1.0
POWER SUPPLY FEEDTHROUGH (dB)
DNL (LSBs)
INL (LSBs)
0.5
0
–0.5
–1.0
–1.5
–2.0
0
16384
32768
CODE
1605 • TPC04
49152
U W
Supply Current vs Temperature
12.0
f
SAMPLE
= 100kHz
Change in CAP Voltage vs
Load Current
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
–80 –70 –60 –50 –40 –30 –20 –10
LOAD CURRENT (mA)
–25
0
25
50
TEMPERATURE (°C)
75
100
0
10
1605 • TPC02
1605 • TPC03
Typical DNL Curve
–20
Power Supply Feedthrough vs
Ripple Frequency
–30
0.5
0
–0.5
–1.0
–1.5
–40
–50
–60
65535
–2.0
0
16384
32768
CODE
1605 • TPC05
–70
49152
65535
1
10
100
1k
10k 100k
RIPPLE FREQUENCY (Hz)
1M
1605 • TPC06
5
