BURR-BROWN ADS7826, ADS7827, ADS7829 User Manual
SAR
Control
D
OUT
Comparator
S/H Amp
CS/SHDN
DCLOCK
+In
V
REF
–In
CDAC
Serial
Interface
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10/8/12-BIT HIGH SPEED 2.7 V microPOWER™ SAMPLING
ANALOG-TO-DIGITAL CONVERTER
FEATURES DESCRIPTION
• High Throughput at Low Supply Voltage
(2.7 V VCC)
– ADS7829: 12-bit 125 KSPS
– ADS7826: 10-bit 200 KSPS
– ADS7827: 8-bit 250 KSPS
• Very Wide Operating Supply VoltageL:
2.7 V to 5.25 V (as Low as 2.0 V With Reduced
Performance)
• Rail-to-Rail, Pseudo Differential Input
• Wide Reference Voltage: 50 mV to V
CC
• Micropower Auto Power-Down:
– Less Than 60 µW at 75 kHz, 2.7 V V
CC
• Low Power Down Current: 3 µA Max
• Ultra Small Chip Scale Package:
8-pin 3 x 3 PDSO (SON, Same Size as QFN)
• SPI™ Compatible Serial Interface
APPLICATIONS
• Battery Operated Systems
• Remote Data Acquisition
• Isolated Data Acquisition
• Simultaneous Sampling, Multichannel
Systems
The ADS7826/27/29 is a family of 10/8/12-bit sampling
analog-to-digital converters (A/D) with assured specifications at 2.7-V supply voltage. It requires very little
power even when operating at the full sample rate. At
lower conversion rates, the high speed of the device
enables it to spend most of its time in the power down
mode— the power dissipation is less than 60 µW at 7.5
kHz.
The ADS7826/27/29 also features operation from 2.0 V
to 5 V, a synchronous serial interface, and a differential
input. The reference voltage can be set to any level
within the range of 50 mV to VCC.
Ultra-low power and small package size make the
ADS7826/27/29 family ideal for battery operated systems. It is also a perfect fit for remote data acquisition
modules, simultaneous multichannel systems, and isolated data acquisition. The ADS7826/27/29 family is
available in a 3 x 3 8-pin PDSO (SON, same size as
QFN) package.
ADS7826
ADS7827
ADS7829
SLAS388–JUNE 2003
microPOWER is a trademark of Texas Instruments.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform tospecifications per the terms ofTexas Instruments
standard warranty. Production processing does not necessarily includetestingof allparameters.
Copyright © 2003, Texas Instruments Incorporated
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ADS7826
ADS7827
ADS7829
SLAS388–JUNE 2003
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
PACKAGE/ORDERING INFORMATION
MAXIMUM LINERARITY ERROR
PRODUCT INTEGRAL DIFFERENTIAL PACKAGE
ADS7829I ±2 ±2 SON-8 -40°C to 85°C F29 ADS7829IDRBR Tape and reel
ADS7829IB ±1.25 -1/1.25 SON-8 -40°C to 85° F29 ADS7829IBDRBR Tape and reel
ADS7826I ±1 ±1 SON-8 -40°C to 85°C F26 ADS7826IDRBR Tape and reel
ADS7827I ±1 ±1 SON-8 -40°C to 85°C F27 ADS7827IDRBR Tape and reel
ADS7829I ±2 ±2 SON-8 -40°C to 85°C F29 ADS7829IDRBT Tape and reel
ADS7829IB ±1.25 -1/1.25 SON-8 -40°C to 85°C F29 ADS7829IBDRBT Tape and reel
ADS7826I ±1 ±1 SON-8 -40°C to 85°C F26 ADS7826IDRBT Tape and reel
ADS7827I ±1 ±1 SON-8 -40°C to 85°C F27 ADS7827IDRBT Tape and reel
(1)
For detail drawing and dimension table, see end of this data sheet or package drawing file on web.
(2)
Performance Grade information is marked on the reel.
(LSB)
SPECIFICATION
TEMPERATURE PACKAGE ORDERING TRANSPORT
(1)
RANGE MARKING
(2)
NUMBER MEDIA
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)
V
CC
Analog input -0.3 V to (VCC+ 0.3 V)
Logic input -0.3 V to 6 V
Case temperature 100°C
Junction temperature 150°C
Storage temperature 125°C
External reference voltage 5.5 V
(1)
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating
conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(1)
6 V
2
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SPECIFICATIONS
At -40°C to 85°C, VCC= 2.7 V, V
= 2.5 V, unless otherwise specified.
ref
ADS7826
ADS7827
ADS7829
SLAS388–JUNE 2003
PARAMETER UNIT
ANALOG INPUT
Full-scale input +In - (-In) 0 V
span
Absolute input +In -0.2 VCC+0.2 -0.2 VCC+0.2 -0.2 VCC+0.2 -0.2 VCC+0.2 V
range
Capacitance 25 25 25 25 pF
Leakage current ±1 ±1 ±1 ±1 µA
SYSTEM PERFORMANCE
Resolution 12 12 10 8 Bits
No missing codes 12 11 10 8 Bits
Integral linearity error -1.25 ±0.4 1.25 -2 ±0.8 2 -1 ±0.3 1 -1 ±0.2 1 LSB
Differential linearity error -1 ±0.4 1.25 -2 ±0.8 2 -1 ±0.3 1 -1 ±0.2 1 LSB
Offset error -3 ±0.3 3 -3 ±0.6 3 -2 ±0.4 2 -1 ±0.4 1 LSB
Gain error -2 ±0.3 2 -2 ±0.6 2 -1 ±0.3 1 -1 ±0.2 1 LSB
Noise 33 33 33 33 µVrms
Power supply rejection 82 82 94 98 dB
SAMPLING DYNAMICS
Conversion time 12 12 10 8 DCLOCK
Acquisition time 1.5 1.5 1.5 1.5 DCLOCK
f
DCLOCK
Throughput 2.7 V ≤ V
(sample rate) ≤ 5.25 V
fsample
DYNAMIC CHARACTERISTICS
Total harmonic distortion -82 -80 -78 -72 dB
SINAD VIN= 2.5 Vpp at 72 70 62 50 dB
Spurious free VIN= 2.5 Vpp at 85 82 81 68 dB
dynamic range 1 kHz
(SFDR)
REFERENCE INPUT
Voltage range 2.7 V ≤VCC≤3.6 V 0.05 VCC-0.2 0.05 VCC-0.2 0.05 VCC-0.2 0.05 VCC-0.2 V
Resistance CS = GND, 5 5 5 5 GΩ
Current drain Full speed at V
DIGITAL INPUT/OUTPUT
Logic family CMOS CMOS CMOS CMOS
Logic levels
V
IH
V
IL
TEST
CONDITIONS
-IN -0.2 1.0 -0.2 1.0 -0.2 1.0 -0.2 1.0 V
CC
(2)
2.0 V ≤ V
CC
(3) (2)
< 2.7 V
1 kHz
f
= 0 Hz
SAMPLE
CS = V
CC
/2 12 60 12 60 20 100 24 120 µA
ref
f
= 7.5 kHz 0.8 0.8 0.8 0.8 µA
SAMPLE
CS = V
CC
IIH= +5 µA 2.0 5.5 2.0 5.5 2.0 5.5 2.0 5.5 V
IIL= +5 µA -0.3 0.8 -0.3 0.8 -0.3 0.8 -0.3 0.8 V
ADS7829IB ADS7829 ADS7826I ADS7827I
MIN TYP MAX MIN TYP MAX MIN TYP MAX MIN TYP MAX
0 V
ref
16 x fsample 16 x fsample 14 x fsample 12 x fsample kHz
125 125 200 250 kHz
75 75 85 100 kHz
5 5 5 5 GΩ
0.001 3 0.001 3 0.001 3 0.001 3 µA
ref
0 V
ref
0 V
ref
V
(1)
Cycles
Cycles
(1)
LSB means Least Significant Bit and is equal to V
/ 2Nwhere N is the resolution of ADC. For example, with V
ref
equal to 2.5 V, one
ref
LSB is 0.61 mV for a 12 bit ADC (ADS7829).
(2)
See the Typical Performance Curves for VCC= 5 V and V
(3)
The maximum clock rate of the ADS7826/27/29 are less than 1.2 MHz at 2 V ≤VCC<2.7 V. The recommended regerence voltage is
ref
= 5 V.
between 1.25 V to 1.024 V.
3
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ADS7826
ADS7827
ADS7829
SLAS388–JUNE 2003
SPECIFICATIONS (continued)
At -40°C to 85°C, VCC= 2.7 V, V
PARAMETER UNIT
V
OH
V
OL
Data format Straight binary Straight binary Straight binary Straight binary
POWER SUPPLY REQUIREMENTS
VCC Operating range 2.7 3.6 2.7 3.6 2.7 3.6 2.7 3.6 V
Quiescent cur- Full speed
rent
Power down CS = V
TEMPERATURE RANGE
Specified performance -40 85 -40 85 -40 85 -40 85 °C
TEST
CONDITIONS
IOH= -250 µA 2.2 2.1 2.1 2.1 V
IOL= 250 µA 0.4 0.4 0.4 0.4 V
(3)
See
f
SAMPLE
f
SAMPLE
(2)
and
(2)
See
(4)
= 7.5 kHz 20 20 20 20 µA
(5)
,
= 7.5 kHz 180 180 180 180 µA
(6)
CC
= 2.5 V, unless otherwise specified.
ref
ADS7829IB ADS7829 ADS7826I ADS7827I
MIN TYP MAX MIN TYP MAX MIN TYP MAX MIN TYP MAX
2.0 2.7 2.0 2.7 2.0 2.7 2.0 2.7 V
3.6 5.25 3.6 5.25 3.6 5.25 3.6 5.25 V
220 350 220 350 250 350 260 350 µA
3 3 3 3 µA
(4)
Full speed: 125 ksps for ADS7829, 200 ksps for ADS7826, and 250 ksps for ADS7827.
(5)
f
= 1.2 MHz, CS = VCCfor 145 clock cycles out of every 160 for the ADS7829I and ADS7829IB.
DCLOCK
(6)
See the Power Dissipation section for more information regarding lower sample rates.
At -40°C to 85°C, VCC= 5 V, V
PARAMETER TEST CONDITIONS UNIT
SYSTEM PERFORMANCE
Resolution 12 12 10 8 Bits
No missing codes 12 11 10 8 Bits
Integral linearity error ±0.6 ±0.8 ±0.15 ±0.1 1 LSB
Differential linearity error ±0.5 ±0.8 ±0.15 ±0.1 1 LSB
ANALOG INPUT
Offset error ±2.6 ±2.6 ±1.2 ±0.7 LSB
Gain error ±1.2 ±1.2 ±0.2 ±0.1 LSB
REFERENCE INPUT
Voltage range 0.05 VCC0.05 VCC0.05 VCC0.05 V
(7)
LSB means Least Significant Bit . With V
= 5 V, unless otherwise specified.
ref
ADS7829IB ADS7829 ADS7826I ADS7827I
MIN TYP MAX MIN TYP MAX MIN TYP MAX MIN TYP MAX
equal to 5 V, one LSB is 1.22 mV for a 12 bit ADC.
ref
CC
(7)
V
4
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8
7
6
5
REF
+IN
−IN
GND
+V
DD
DCLOCK
DOUT
CS
/ SHDN
PDSO (SON−8) PACKAGE
(TOP VIEW)
1
2
3
4
ADS7826
ADS7827
ADS7829
SLAS388–JUNE 2003
DEVICE INFORMATION
PIN DESCRIPTION
Terminal Functions
PIN NAME DESCRIPTION
1 V
2 +In Noninverting input
3 -In Inverting input. Connect to ground or to remote ground sense point.
4 GND Ground
5 CS/SHDN Chip select when LOW, shutdown mode when HIGH
6 DOUT The serial output data word is comprised of 12 bits of data. In operation the data is valid
7 DCLOCK Data Clock synchronizes the serial data transfer and determines conversion speed.
8 +V
ref
CC
Reference input
on the falling edge of DCLOCK. The second clock pulse after the falling edge of CS
enables the serial output. After one null bit, the data is valid for the next 12 edges.
Power supply
5
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-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
0 512 1024 1536 2048 2560 3072 3584
Integral Linearity - LSB
Decimal Code
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
0 128 256 384 512 640 768 896
Decimal Code
Integral Linearity - LSB
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 32 64 96 128 160 192 224
Decimal Code
Integral Linearity - LSB
ADS7826
ADS7827
ADS7829
SLAS388–JUNE 2003
TYPICAL CHARACTERISTICS
At TA= 25°C, VCC= 2.7 V, V
ADS7829 INTEGRAL LINEARITY
ADS7826 INTEGRAL LINEARITY
= 25 V, (unless otherwise specified)
ref
Figure 1
ADS7827 INTEGRAL LINEARITY
6
Figure 2
Figure 3
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