Rainbow Electronics DS8102 User Manual
General Description
The DS8102 is a stand-alone, dual-channel, deltasigma modulator that converts measurements from two
differential analog input pairs into a Manchester-encoded output bit stream that can be processed by a companion microcontroller such as the MAXQ3108. One
channel operates at a fixed 1x gain, while the other
operates at a pin-selectable gain of 1x, 4x, 16x, or 32x.
The DS8102 includes an internal power-supply monitor,
on-board voltage reference, and low-power oscillator to
reduce the number of external components required for
data acquisition.
The Manchester-encoded output from the DS8102
combines pulse-density-modulated measurement values from both differential input channels with a synchronization bit stream and is transmitted over a single
pin. This transmission scheme is ideal for split voltage
domain applications where the DS8102 and other “hot”side components must be electrically isolated from
“cold” low-voltage components such as a companion
microcontroller. In this type of application, the DS8102
can be capacitively coupled to a companion microcontroller with only two connection points required
(MNOUT and DGND).
The MAXQ3108 dual-core microcontroller, which
includes specialized Manchester bit-stream decoding
inputs and sinc3 filters, is specifically designed to act
as a companion microcontroller for up to three DS8102
devices. This configuration, which supports up to six
differential analog input channels, is well suited for
three-phase electricity-metering applications.
Applications
Single-Phase Electricity Metering
Three-Phase Electricity Metering
Power-Line Conditioning
Electrochemical and Optical Sensors
Industrial Control
Data-Acquisition Systems and Data Loggers
Features
♦ Dual Delta-Sigma 2nd-Order Modulators
Channel 0: Pin-Selectable Gain of 1x, 4x, 16x,
or 32x
Channel 1: Fixed Gain of 1x
♦ Selectable Internal or External Voltage Reference
♦ Manchester-Encoded Bit Stream Output
Includes Synchronization Bits to Allow Clock
Recovery
Single-Pin Transmission Scheme Simplifies
Electrical Isolation Using Capacitive Coupling
♦ Selectable Internal or External Clock Source
♦ Integrated Low-Power 8MHz Oscillator
♦ Operating Mode
Active Mode (8MHz, V
DD
= 3.6V): 3.5mA
DS8102
Dual Delta-Sigma Modulator and Encoder
________________________________________________________________
Maxim Integrated Products
1
Pin Configuration
Ordering Information
Rev 1; 2/09
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
PART TEMP RANGE PIN-PACKAGE
DS8102+ -40°C to +85°C 16 TSSOP
Typical Operating Circuit appears at end of data sheet.
MAXQ is a trademark of Maxim Integrated Products, Inc.
TOP VIEW
DGND
AGND
REF
AN1+
AN0+
DD
+
DS8102
TSSOP
161V
DD
APDREF
152
143 RSTV
134 MNOUTAN1-
CLKIO
125
G1AN0-
116
G0
107
CLKSELV
98
DS8102
Dual Delta-Sigma Modulator and Encoder
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VDD= 2.7V to 3.6V, TA= -40°C to +85°C, f
CLK
= 8MHz, V
REF
= internal, OSR = 128, unless otherwise noted.) (Note 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 in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Voltage Range on VDDRelative to DGND.............-0.3V to +4.0V
Voltage Range on V
DD
Relative to AGND.............-0.3V to +4.0V
Voltage Range on AGND Relative to DGND .........-0.3V to +0.3V
Voltage Range on Any Pin Relative to DGND
Except AN0+, AN0-, and AN1+, AN1- ...............-0.3V to +4.0V
Voltage Range on AN0+, AN0-, AN1+, and AN1-
Relative to AGND ...............................................-4.0V to +4.0V
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Soldering Temperature...........................Refer to the IPC/JEDEC
J-STD-020 Specification.
PARAMETER SYMBOL CONDITIONS MIN
Supply Voltage VDD V
Power-Fail Reset Voltage V
Active VDD Current IDD Normal operation 3.5 5.0 mA
Shutdown (Power-Down) V
Current
Input Low Voltage VIL DGND 0.3 x VDD V
Input High Voltage VIH 0.7 x VDD VDD V
Output Low Voltage
(CLKIO, MNOUT)
Output High Voltage
(CLKIO, MNOUT)
Input/Output Pin Capacitance CIO (Note 3) 15 pF
Input Leakage Current (All Inputs) IL -100 +100 nA
CLOCK SOURCE
External Cloc k Input Frequency f
External Clock Input Period t
External Cloc k Input Dut y Cycle t
Internal Oscillator Output
Frequency
Internal Oscillator Output Duty
Cycle
ANALOG-TO-DIGITAL CONVERTER
AFE Warmup Delay t
Reference Buffer Warmup Delay t
Decimator Output (Note 6)
Integral Nonlinearity INL (Notes 1, 6) ±0.01 %FSR
Offset Error Gain = 1 (Note 6) 1.4 mV
DD
XCLK-CLCL
XCLK -DUTY
t
ICLK-DUTY
Monitors VDD 2.7 2.8 2.99 V
RST
I
RST = 0 or VDD < V
STOP
V
IOL = 4mA DGND 0.4 V
OL
IOH = -4mA VDD - 0.4 V
V
OH
CLKSEL = 1 DC 8 MHz
XCLK
CLKSEL = 1 125 ns
CLKSEL = 1 40 60 %
f
CLKSEL = 0 7.5 8.0 8.5 MHz
ICLK
CLKSEL = 0 47.8 49.1 49.7 %
f
WU1
WU2
ICLK
f
ICLK
OSR = 32 16
OSR = 64 19
OSR = 128 22
OSR = 256 24
TYP
(Note 2)
3.3 3.6 V
RST
2 nA
RST
= 8MHz (Notes 1, 4) 1.02 ms
= 8MHz (Notes 1, 5) 7.17 ms
MAX UNITS
Bits
DS8102
Dual Delta-Sigma Modulator and Encoder
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VDD= 2.7V to 3.6V, TA= -40°C to +85°C, f
CLK
= 8MHz, V
REF
= internal, OSR = 128, unless otherwise noted.) (Note 1)
Note 1: Specifications to -40°C are guaranteed by design and not production tested.
Note 2: Typical values are not guaranteed. These values are measured at room temperature, V
DD
= 3.3V.
Note 3: These numbers are guaranteed by design and are not tested.
Note 4: Calculated as t
WU1
= 1/f
ICLK
x 8192.
Note 5: Calculated as t
WU2
= 1/f
ICLK
x 57,344.
Note 6: Parameter specifications are based upon the presence of an external cubic sinc filter (as implemented in the MAXQ3108)
for generating full ADC output codewords.
Note 7: f
S
= f
CLK
/12. f
CLK
is the system clock frequency.
Note 8: This is a function of input sampling capacitance (C
IN
) and sampling frequency, and can be approximated as 6/(f
CLK
x CIN).
Note 9: Z
IN
(differential) = 2 x ZIN(single-ended).
PARAMETER SYMBOL CONDITIONS MIN
ANALOG-TO-DIGITAL CONVERTER DYNAMIC SPECIFICATIONS
DC Power-Supply Rejection Ratio PSRR
Signal-to-Noise Ratio SINAD
Total Harmonic Distortion
(to 21st Harmon ic)
ANALOG-TO-DIGITAL CONVERTER INPUTS
Input Voltage Range AN0+, AN0-, AN1+, and AN1- to AGND -1 +1 V
Input Sampling Capacitance
(Note 1)
Input Sampl ing Rate fS Cloc k at 8MHz (Note 7) 0.667 MHz
Input Impedance to AGND for
8MHz (Note 8)
Differential Input Impedance for
8MHz (Note 9)
Input Bandwidth (-3dB) 7 kHz
External Reference Input Voltage V
External Reference Input
Sampling Capacitance
Reference Input Sampling Rate fS 0.67 1 MHz
INTERNAL REFERENCE
Reference Output Voltage 1.24 V
Reference Output Temperature
Coefficient
V
DD
100mV ripple on V
VDD = 3.6V, gain = 1, AN0 = 500mV
sinewave at 62.5Hz
V
DD
sinewave at 62.5Hz
V
THD
C
IN
REF
2 pF
±30 ppm/°C
DD
sinewave at 62.5Hz
Gain = 1 1
Gain = 4 4
Gain = 16 16
Gain = 32 32
Gain = 1 750
Gain = 4 187
Gain = 16 47
Gain = 32 23.4
Gain = 1 1500
Gain = 4 375
Gain = 16 94
Gain = 32 46.9
1.2 1.25 1.3 V
= 3.0V to 3.6V, AN0+ = AN0- = AGND,
DD
,
P-P
= 3.6V, gain = 32, AN0 = 20mV
= 3.6V, gain = 32, AN0 = 20mV
P-P
P-P
,
,
95 dB
70 85
70 85
-95 -70 dB
TYP
(Note 2)
MAX UNITS
dB
pF
k
k
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