Document
Features
n Single 5V Supply n Sample Rate: 100ksps n 8-Channel Multiplexer with ±30V Protection n ±10V Bipolar Input Range
Single Ended or Differential n ±3LSB INL for the LTC1856, ±1.5LSB INL for the
LTC1855, ±1LSB INL for the LTC1854 n Power Dissipation: 40mW (Typ) n SPI/MICROWIRE™ Compatible Serial I/O n Power Shutdown: Nap and Sleep n SINAD: 87dB (LTC1856) n Operates with Internal or External Reference n Internal Synchronized Clock n 28-Pin SSOP Package
Applications
n Industrial Process Control n Multiplexed Data Acquisition Systems n High Speed Data Acquisition for PCs n Digital Signal Processing
LTC1854/LTC1855/LTC1856 8-Channel, ±10V Input
12-/14-/16-Bit, 100ksps ADC Converters with Shutdown
Description
The LTC®1854/LTC1855/LTC1856 are 8-channel, low power, 12-/14-/16-bit, 100ksps, analog-to-digital converters (ADCs). These ADCs operate from a single 5V supply and the 8‑channel multiplexer can be programmed for single-ended inputs, pairs of differential inputs, or combinations of both. In addition, all channels are fault protected to ±30V. A fault condition on any channel will not affect the conversion result of the selected channel. An onboard precision reference minimizes external components. Power dissipation is 40mW at 100ksps and lower in two power shutdown modes (27.5mW in Nap mode and 40µW in Sleep mode.) DC specifications include ±3LSB INL for the LTC1856, ±1.5LSB INL for the LTC1855 and ±1LSB for the LTC1854. The internal clock is trimmed for 5µs maximum conversion time and the sampling rate is guaranteed at 100ksps. A separate convert start input and data ready signal (BUSY) ease connections to FIFOs, DSPs and microprocessors.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
100kHz, 12-Bit/14-/16-Bit Sampling ADC
SOFTWARE-PROGRAMMABLE SINGLE-ENDED OR
DIFFERENTIAL INPUTS ±10V BIPOLAR INPUT RANGE
COM CONVST
CH0 LTC1854/ RD CH1 LTC1855/ SCK CH2 LTC1856 SDI
CH3 DGND
CH4 SDO
CH5 BUSY
CH6 OVDD
CH7 MUXOUT+ MUXOUT–
DVDD AVDD AGND3
ADC+
AGND2
ADC–
REFCOMP
AGND1
VREF
µP CONTROL LINES 0.1µF 10µF 10µF 0.1µF 10µF 1µF 10µF 0.1µF
3V TO 5V 5V 5V 0.1µF
2.5V
INL (LSB)
LTC1856 Typical INL Curve
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0 –32768 –16384
0 CODE
16384 32767
185456 G01
1854565af
1
LTC1854/LTC1855/LTC1856
Absolute Maximum Ratings
(Notes 1, 2)
Supply Voltage (OVDD = DVDD = AVDD = VDD)............. 6V Ground Voltage Difference DGND, AGND1, AGND2, AGND3........................ ±0.3V Analog Input Voltage ADC+, ADC– (Note 3)....................(AGND1 – 0.3V) to (AVDD + 0.3V) CH0-CH7, COM .................................................... ±30V Digital Input Voltage (Note 4) .......(DGND – 0.3V) to 10V Digital Output Voltage .....(DGND – 0.3V) to (DVDD + 0.3V) Power Dissipation................................................. 500mW Operating Temperature Range LTC1854C/LTC1855C/LTC1856C............... 0°C to 70°C LTC1854I/LTC1855I/LTC1856I.............. – 40°C to 85°C Storage Temperature Range.................... –65°C to 150°C Lead Temperature (Soldering, 10 sec)................... 300°C
Package/order information
TOP VIEW
COM 1
CH0 2
CH1 3
CH2 4
CH3 5
CH4 6
CH5 7
CH6 8
CH7 MUXOUT+ MUXOUT–
ADC+ ADC–
9 10 11 12 13
AGND1 14
28 CONVST 27 RD 26 SCK 25 SDI 24 DGND 23 SDO 22 BUSY 21 OVDD 20 DVDD 19 AVDD 18 AGND3 17 AGND2 16 REFCOMP 15 VREF
G PACKAGE 28-LEAD PLASTIC SSOP
TJMAX = 125°C, θJA = 160°C/W EXPOSED PAD (PIN #) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER
LTC1854CG LTC1854IG
LTC1855CG LTC1855IG
LTC1856CG LTC1856IG
Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
converter and multiplexer characteristics
The l denotes the specifications which apply over MUXOUT connected to ADC inputs. (Notes 5, 6)
the
full
operating
temperature
range,
otherwise
specifications
are
at
TA
=
25°C.
PARAMETER Resolution
CONDITIONS
LTC1854 MIN TYP MAX l 12
LTC1855 MIN TYP MAX 14
LTC1856 MIN TYP MAX 15
UNITS Bits
No Missing Codes
l 12 14 15
Bits
Transition Noise Integral Linearity Error
(Note 7)
0.06 l ±1
0.25 ±1.5
1 LSBRMS ±3 LSB
Differential Linearity Error
l –1
1 –1
1.5 –2
4 LSB
Bipolar Zero Error
(Note 8)
l ±5 ±8 ±23 LSB
Bipolar Zero Error Drift
±0.1 ±0.1 ±0.1 ppm/°C
Bipolar Zero Error Match
3 4 10 LSB
Bipolar Full-Scale Error Bipolar Full-Scale Error Drift Bipolar Full-Scale Error Match
External Reference (Note 11) l Internal Reference (Note 11) External Reference Internal Reference
±0.34 ±0.45 ±2.5 ±7
5
±0.14 ±0.40 ±2.5 ±7
10
±0.1 % ±0.4 % ±2.5 ppm/°C ±7 ppm/°C 15 LSB
Input Common Mode Range
l ±10 ±+.