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LTC2433-1 Differential Input 16-Bit No Latency ∆Σ ADC
FEATURES
s s s s s s s s
DESCRIPTIO
s
s s s s
16-Bit Differential ADC in a Tiny MSOP Low Supply Current: 200µA, 4µA in Autosleep Rail-to-Rail Differential Input/Reference 0.12LSB INL, No Missing Codes 0.16LSB Full-Scale Error and 5µV Offset 1.45µV RMS Noise, Independent of VREF Very Low Transition Noise: <0.02LSB Operates with a Reference as Low as 100mV with 16-Bit Resolution Internal Oscillator—No External Components Required 87dB Min, Simultaneous 50Hz and 60Hz Notch Filter Single Supply 2.7V to 5.5V Operation Pin Compatible with the 20/24-Bit LTC2431/LTC2411 Available in 10-Lead MSOP Package
The LTC®2433-1 is a differential input micropower 16-bit No Latency ∆ΣTM analog-to-digital converter with an integrated oscillator. It provides 0.12LSB INL and 1.45µV RMS noise independent of VREF. It uses delta-sigma technology and provides single conversion settling of the digital filter. Through a single pin, the LTC2433-1 can be configured for better than 87dB input differential mode rejection at 50Hz and 60Hz ±2%, or it can be driven by an external oscillator for a user defined rejection frequency. The internal oscillator requires no external frequency setting components. The converter accepts any external differential reference voltage from 0.1V to VCC for flexible ratiometric and remote sensing measurement configurations. The fullscale differential input range is from – 0.5 • VREF to 0.5 • VREF. The reference common mode voltage, VREFCM, and the input common mode voltage, VINCM, may be independently set anywhere between GND and VCC. The DC common mode input rejection is better than 140dB. The LTC2433-1 communicates through a flexible 3-wire digital interface which is compatible with SPI and MICROWIRETM protocols.
, LTC and LT are registered trademarks of Linear Technology Corporation. No Latency ∆Σ is a trademark of Linear Technology Corporation. MICROWIRE is a trademark of National Semiconductor Corporation.
APPLICATIO S
s s s s s s s s
Direct Sensor Digitizer Weight Scales Direct Temperature Measurement Gas Analyzers Strain-Gage Transducers Instrumentation Data Acquisition Industrial Process Control
TYPICAL APPLICATIO
5V REF 1µF 4.9k (100mV) 100Ω 1 2 4 VCC
Minimum Resolvable Signal vs VREF
90 MINIMUM RESOLVABLE SIGNAL (µV)* 80 70 60 50 40 30 20 10 0 0 5 4 3 2 VREF (V) 24331 TA02 *FOR VREF ≥ 0.5V THE RESOLUTION IS LIMITED BY STEP SIZE 1
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FO
10
REF + IN+ LTC2433-1 IN– REF – GND SCK SDO CS 9 8 7
24331 TA01
= EXTERNAL CLOCK SOURCE = INTERNAL OSC/SIMULTANEOUS 50Hz/60Hz REJECTION
5 3 6
3-WIRE SPI INTERFACE
U
U
U
1
LTC2433-1
ABSOLUTE
(Notes 1, 2)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
LTC2433-1CMS LTC2433-1IMS
Supply Voltage (VCC) to GND .......................– 0.3V to 7V Analog Input Voltage to GND .................................... – 0.3V to (VCC + 0.3V) Reference Input Voltage to GND .................................... – 0.3V to (VCC + 0.3V) Digital Input Voltage to GND ........ – 0.3V to (VCC + 0.3V) Digital Output Voltage to GND ..... – 0.3V to (VCC + 0.3V) Operating Temperature Range LTC2433-1C ............................................ 0°C to 70°C LTC2433-1I ........................................ – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART NUMBER
TOP VIEW VCC REF+ REF – IN+ IN– 1 2 3 4 5 10 9 8 7 6 FO SCK SDO CS GND
MS10 PACKAGE 10-LEAD PLASTIC MSOP
TJMAX = 125°C, θJA = 110°C/W
MS PART MARKING LTAEY LTAEZ
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 3, 4, 6)
PARAMETER Resolution (No Missing Codes) Integral Nonlinearity (Note 15) CONDITIONS 0.1V ≤ VREF ≤ VCC, –0.5 • VREF ≤ VIN ≤ 0.5 • VREF, (Note 5)
q
ELECTRICAL CHARACTERISTICS
MIN 16
TYP 0.06 0.12 0.30 5 20
MAX
UNITS Bits LSB LSB LSB µV nV/°C
5V ≤ VCC ≤ 5.5V, REF+ = 2.5V, REF– = GND, VINCM = 1.25V, (Note 6) q 5V ≤ VCC ≤ 5.5V, REF+ = 5V, REF– = GND, VINCM = 2.5V, (Note 6) REF+ = 2.5V, REF– = GND, VINCM = 1.25V, (Note 6) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN+ = IN– ≤ VCC, (Note 13) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN+ = IN– ≤ VCC 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.75REF+, IN– = 0.25 • REF+ 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.75REF+, IN– = 0.25 • REF+ 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.25 • REF+, IN– = 0.75 • REF+ 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.25 • REF+, IN– = 0.75 • REF+ 5V ≤ VCC ≤ 5.5V, REF+ = 2.5V, REF– = GND, VINCM = 1.25V 5V ≤ VCC ≤ 5.5V, REF+ = 5V, REF– = GND, VINCM = 2.5V REF+ = 2.5V, REF– = GND, VINCM = 1.25V, (Note 6) 5V ≤ VCC ≤ 5.5V, REF+ = 5V, REF – = GND, GND ≤ IN– = IN+ ≤ VCC, (Note 12)
q q q
1.25 20
Offset Error (Note 15) Offset Error Drift Positive Full-Scale Error (Note 15) Positive Full-Scale Error Drift Negative Full-Scale Error (Note 15) Negative Full-Scale Error Drift Total Unadjusted Error
0.16 0.04 0.16 0.04 0.20 0.20 0.25 1.45
1.25
ppm of VREF/°C 1.25 LSB ppm of VREF/°C LSB LSB LSB µVRMS
Output Noise
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2
U
LSB
W
U
U
W W
W
LTC2433-1
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 3, 4)
PARAMETER Input Common Mode Rejection DC Input Common Mode Rejection 49Hz to 61.2Hz Input Normal Mode Rejection 49Hz to 61.2Hz Reference Common Mode Rejection DC Power Supply Rejection, DC Power Supply Rejection, Simultaneous 50Hz/60Hz ±2% CONDITIONS 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN– = IN+ ≤ VCC (Note 5) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN – = IN+ ≤ VCC, (Notes 5, 7) (Note 5, 7) 2.5V ≤ REF+ ≤ VCC, GND ≤ REF– ≤ 2.5V, VREF = 2.5V, IN– = IN+ = GND (Note 5) REF+ = 2.5V, REF– = GND, IN– = IN+ = GND REF+ = 2.5V, REF– = GND, IN– = IN+ = GND, (Note 7)
q q q q
CO VERTER CHARACTERISTICS
A ALOG I PUT A D REFERE CE
SYMBOL IN+ IN– VIN REF+ REF– VREF CS (IN+) CS CS (IN–) (REF+) (IN+) (IN–) (REF–) PARAMETER Absolute/Common Mode IN+ Voltage Absolute/Common Mode IN– Voltage Input Differential Voltage Range (IN+ – IN–) Absolute/Common Mode REF+ Voltage Absolute/Common Mode REF– Voltage Reference Differential Voltage Range (REF+ – REF–) IN+ Sampling Capacitance IN– Sampling Capacitance REF+ Sampling Capacitance REF– Sampling Capacitance IN+ IN– DC Leakage Current DC Leakage Current
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3)
CONDITIONS
q q q q q q
CS (REF–) IDC_LEAK IDC_LEAK IDC_LEAK
IDC_LEAK (REF+)
REF+ DC Leakage Current REF– DC Leakage Current
U
U
U
U
MIN 130 140 87 130
TYP 140
MAX
UNITS dB dB dB
140 120 120
dB dB dB
U
MIN GND – 0.3 GND – 0.3 –VREF/2 0.1 GND 0.1
TYP
MAX VCC + 0.3 VCC + 0.3 VREF/2 VCC VCC – 0.1 VCC
UNITS V V V V V V pF pF pF pF
6 6 6 6 CS = VCC CS = VCC CS = VCC = 5V, IN+ = GND = 5V, IN – = 5.5V = 5V, REF – = GND
q q q q
–100 –100 –100 –100
1 1 1 1
100 100 100 100
nA nA nA nA
CS = VCC = 5V, REF+ = 5.5V
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3
LTC2433-1 DIGITAL I PUTS A D DIGITAL OUTPUTS
SYMBOL VIH VIL VIH VIL IIN IIN CIN CIN VOH VOL VOH VOL IOZ PARAMETER High Level Input Voltage CS, FO Low Level Input Voltage CS, FO High Level Input Voltage SCK Low Level Input Voltage SCK Digital Input Current CS, FO Digital Input Current SCK Digital Input Capacitance CS, FO Digital Input Capacitance SCK High Level Output Voltage SDO Low Level Output Voltage SDO High Level Output Voltage SCK Low Level Output Voltage SCK Hi-Z Output Leakage SDO (Note 8) IO = –800µA IO = 1.6mA IO = –800µA (Note 9) IO = 1.6mA (Note 9)
q q q q q
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3)
CONDITIONS 2.7V ≤ VCC ≤ 5.5V 2.7V ≤ VCC ≤ 3.3V 4.5V ≤ VCC ≤ 5.5V 2.7V ≤ VCC ≤ 5.5V 2.7V ≤ VCC ≤ 5.5V (Note 8) 2.7V ≤ VCC ≤ 3.3V (Note 8) 4.5V ≤ VCC ≤ 5.5V (Note 8) 2.7V ≤ VCC ≤ 5.5V (Note 8) 0V ≤ VIN ≤ VCC 0V ≤ VIN ≤ VCC (Note 8)
q q q q q q
POWER REQUIRE E TS
SYMBOL VCC ICC PARAMETER Supply Voltage Supply Current Conversion Mode Sleep Mode Sleep Mode
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3)
CONDITIONS
q
4
U W
U
U
MIN 2.5 2.0
TYP
MAX
UNITS V V
0.8 0.6 2.5 2.0 0.8 0.6 –10 –10 10 10 VCC – 0.5 0.4 VCC – 0.5 0.4 –10 10 10 10
V V V V V V µA µA pF pF V V V V µA
MIN 2.7
TYP
MAX 5.5
UNITS V µA µA µA
CS = 0V (Note 14) CS = VCC (Notes 11, 14) CS = VCC, 2.7V ≤ VCC ≤ 3.3V (Notes 11, 14)
q q
200 4 2
300 13
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LTC2433-1
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3)
SYMBOL fEOSC tHEO tLEO tCONV fISCK DISCK fESCK tLESCK tHESCK tDOUT_ISCK tDOUT_ESCK t1 t2 t3 t4 tKQMAX tKQMIN t5 t6 PARAMETER External Oscillator Frequency Range External Oscillator High Period External Oscillator Low Period Conversion Time Internal SCK Frequency Internal SCK Duty Cycle External SCK Frequency Range External SCK Low Period External SCK High Period Internal SCK 19-Bit Data Output Time External SCK 19-Bit Data Output Time CS ↓ to SDO Low Z CS ↑ to SDO High Z CS ↓ to SCK ↓ CS ↓ to SCK ↑ SCK ↓ to SDO Valid SDO Hold After SCK ↓ SCK Set-Up Before CS ↓ SCK Hold After CS ↓ (Note 5) (Note 9) (Note 8) FO = 0V External Oscillator (Note 10) Internal Oscillator (Note 9) External Oscillator (Notes 9, 10) (Note 9) (Note 8) (Note 8) (Note 8) Internal Oscillator (Notes 9, 1
