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TL/H/11225

ADC10154, ADC10158 10-Bit Plus Sign 4 ms ADCs with

4- or 8-Channel MUX, Track/Hold and Reference

January 1995

ADC10154, ADC10158 10-Bit Plus Sign 4 ms ADCs

with 4- or 8-Channel MUX, Track/Hold and Reference

General Description

The ADC10154 and ADC10158 are CMOS 10-bit plus sign

successive approximation A/D converters with versatile an-

alog input multiplexers, track/hold function and a 2.5V

band-gap reference. The 4-channel or 8-channel multiplex-

ers can be software configured for single-ended, differential

or pseudo-differential modes of operation.

The input track/hold is implemented using a capacitive ar-

ray and sampled-data comparator.

Resolution can be programmed to be 8-bit, 8-bit plus sign,

10-bit or 10-bit plus sign. Lower-resolution conversions can

be performed faster.

The variable resolution output data word is read in two

bytes, and can be formatted left justified or right justified,

high byte first.

Applications

Process control

Instrumentation

Test equipment

Features

4- or 8- channel configurable multiplexer

Analog input track/hold function

0V to 5V analog input range with single

5V power

supply

5V to

5V analog input voltage range with

5V sup-

plies

Fully tested in unipolar (single

5V supply) and bipolar

(dual

5V supplies) operation

Programmable resolution/speed and output data format

Ratiometric or Absolute voltage reference operation

No zero or full scale adjustment required

No missing codes over temperature

Easy microprocessor interface

Key Specifications

Resolution 10-bit plus sign

Integral linearity error

1 LSB (max)

Unipolar power dissipation 33 mW (max)

Conversion time (10-bit

sign) 4.4 ms (max)

Conversion time (8-bit) 3.2 ms (max)

Sampling rate (10-bit

sign) 166 kHz

Sampling rate (8-bit) 207 kHz

Band-gap reference 2.5V

2.0% (max)

ADC10158 Simplified Block Diagram

TL/H/11225–1

TRI-STATE

is a registered trademark of National Semiconductor Corporation.

1995 National Semiconductor Corporation RRD-B30M75/Printed in U. S. A.

Summary of content (26 pages)

PAGE 1
ADC10154, ADC10158 10-Bit Plus Sign 4 ms ADCs with 4- or 8-Channel MUX, Track/Hold and Reference General Description Features The ADC10154 and ADC10158 are CMOS 10-bit plus sign successive approximation A/D converters with versatile analog input multiplexers, track/hold function and a 2.5V band-gap reference. The 4-channel or 8-channel multiplexers can be software configured for single-ended, differential or pseudo-differential modes of operation.
PAGE 2
Absolute Maximum Ratings (Notes 1 & 3) Operating Ratings (Notes 2 & 3) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Temperature Range ADC10154CIN, ADC10154CIWM, ADC10158CIN, ADC10158CIWM Positive Supply Voltage (V a e AV a e DV a ) 6.5V b 6.5V Negative Supply Voltage (Vb) 13V Total Supply Voltage (V a b Vb) Total Reference Voltage (VREF a b VREFb) 6.6V Voltage at Inputs and Outputs Vb b 0.
PAGE 3
Electrical Characteristics The following specifications apply for V a e AV a e DV a e a 5.0 VDC, VREF a e 5.000 VDC, VREFb e GND, Vb e GND for unipolar operation or Vb e b5.0 VDC for bipolar operation, and fCLK e 5.0 MHz unless otherwise specified. Boldface limits apply for TA e TJ e TMIN to TMAX; all other limits TA e TJ e 25§ C.
PAGE 4
Electrical Characteristics The following specifications apply for V a e AV a e DV a e a 5.0 VDC, VREF a e 5.000 VDC, VREFb e GND, Vb e GND for unipolar operation or Vb e b5.0 VDC for bipolar operation, and fCLK e 5.0 MHz unless otherwise specified. Boldface limits apply for TA e TJ e TMIN to TMAX; all other limits TA e TJ e 25§ C.
PAGE 5
Electrical Characteristics The following specifications apply for V a e AV a e DV a e a 5.0 VDC, VREF a e 5.000 VDC, VREFb e GND, Vb e GND for unipolar operation or Vb e b5.0 VDC for bipolar operation, tr e tf e 3 ns and fCLK e 5.0 MHz unless otherwise specified. Boldface limits apply for TA e TJ e TMIN to TMAX; all other limits TA e TJ e 25§ C. (Note 16) (Continued) Symbol Parameter Conditions Typical (Note 10) Limits (Note 11) Units (Limit) 8 10 5.
PAGE 6
Electrical Characteristics The following specifications apply for V a e AV a e DV a e a 5.0 VDC, VREF a e 5.000 VDC, VREFb e GND, Vb e GND for unipolar operation or Vb e b5.0 VDC for bipolar operation, tr e tf e 3 ns and fCLK e 5.0 MHz unless otherwise specified. Boldface limits apply for TA e TJ e TMIN to TMAX; all other limits TA e TJ e 25§ C.
PAGE 7
Electrical Characteristics (Continued) Note 9: A diode exists between AV a and DV a as shown below. TL/H/11225 – 5 To guarantee accuracy, it is required that the AV a and DV a be connected together to a power supply with separate bypass filter at each V a pin. Note 10: Typicals are at TJ e TA e 25§ C and represent most likely parametric norm. Note 11: Tested limits are guaranteed to National’s AOQL (Average Outgoing Quality Level). Note 12: One LSB is referenced to 10 bits of resolution.
PAGE 8
Electrical Characteristics (Continued) TL/H/11225 – 6 FIGURE 1A. Transfer Characteristic TL/H/11225 – 7 FIGURE 1B.
PAGE 9
Typical Converter Performance Characteristics Total Positive Supply Current (DI a a AI a ) vs Temperature Total Positive Power Supply Current (DI a a AI a ) vs Clock Frequency Offset Error vs Temperature Offset Error vs Reference Voltage Linearity Error vs Temperature Linearity Error vs Reference Voltage Linearity Error vs Clock Frequency Spectral Response with 50 kHz Sine Wave 10-Bit Unsigned Signal-to-Noise a THD Ratio vs Input Signal Level TL/H/11225 – 8 9
PAGE 10
Typical Reference Performance Characteristics Load Regulation Line Regulation (3 Typical Parts) Output Drift vs Temperature (3 Typical Parts) Available Output Current vs Supply Voltage TL/H/11225 – 9 10
PAGE 11
Leakage Current Test Circuit TL/H/11225 – 10 TRI-STATE Test Circuits and Waveforms TL/H/11225 – 12 TL/H/11225 – 11 TL/H/11225 – 14 TL/H/11225 – 13 11
PAGE 12
Timing Diagrams TL/H/11225 – 15 DIAGRAM 1. Starting a Conversion with New MUX Channel and Output Configuration TL/H/11225 – 16 DIAGRAM 2.
PAGE 13
Timing Diagrams (Continued) TL/H/11225 – 17 DIAGRAM 3. Reading the Conversion Result Multiplexer Addressing and Output Data Configuration Tables TABLE I.
PAGE 14
Multiplexer Addressing and Output Data Configuration Tables (Continued) TABLE II.
PAGE 15
TL/H/11225 – 18 Detailed Block Diagram 15
PAGE 16
Connection Diagrams Dual-In Line and SO Packages TL/H/11225–2 Top View Order Number ADC10154 NS Package Numbers J24A, M24B or N24A TL/H/11225 – 3 Top View Order Number ADC10158 NS Package Numbers J28A, M28B or N28B 1.0 Pin Descriptions AV a This is the positive analog supply. This pin should be bypassed with a 0.1 mF ceramic capacitor and a 10 mF tantalum capacitor to the system analog ground. DV a This is the positive digital supply. This supply pin also needs to be bypassed with 0.
PAGE 17
2.0 Functional Description held and the actual conversion begins. The number of clocks required for a conversion is given in the following table: The ADC10154 and ADC10158 use successive approximation to digitize an analog input voltage. Additional logic has been incorporated in the devices to allow for the programmability of the resolution, conversion time and digital output format. A capacitive array and a resistive ladder structure are used in the DAC portion of the A/D converters.
PAGE 18
2.0 Functional Description (Continued) The switch position information at the completion of the successive approximation routine is a direct representation of the digital output. This information is then manipulated by the Digital Output decoder to the programmed format. The reformatted data is then available to be strobed onto the data bus (DB0 – DB7) via the digital output buffers by taking CS and RD low. Digital Interface Hints: # Reads and writes can be completely asynchronous to CLK.
PAGE 19
3.0 Applications Information (Continued) capacitor will yield a typical noise floor of 200 nVrms/0Hz. The 2.5V reference output is referred to the negative supply pin (Vb). Therefore, the voltage at VREFOut will always be 2.5V greater than the voltage applied to Vb. Applying this voltage to VREF a with VREFb tied to Vb will yield an analog voltage span of 2.5V. In bipolar operation the voltage at VREFOut will be at b2.5V when Vb is tied to b5V.
PAGE 20
3.0 Applications Information (Continued) The minimum value of VREF (VREF e VREF a b VREFb) can be quite small (see Typical Performance Characteristics) to allow direct conversion of transducer outputs providing less than a 5V output span. Particular care must be taken with regard to noise pickup, circuit layout and system error voltage sources when operating with a reduced span due to the increased sensitivity of the converter (1 LSB equals VREF/2n).
PAGE 21
3.0 Applications Information (Continued) SNR vs Input Frequency TL/H/11225 – 23 FIGURE 5. Analog Input Model The curve ‘‘Signal to Noise Ratio vs. Output Frequency’’ (Figure 6) gives an indication of the usable bandwidth of the ADC10154/ADC10158. The signal-to-noise ratio of an ideal A/D is the ratio of the RMS value of the full scale input signal amplitude to the value of the total error amplitude (including noise) caused by the transfer function of the A/D.
PAGE 22
3.0 Applications Information (Continued) Protecting the Analog Inputs (R1 a R2)//R3 s 1k TL/H/11225 – 25 Note 1: Diodes are 1N914. Note 2: The protection diodes should be able to withstand the output current of the op amp under current limit. Zero-Shift and Span-Adjust for Signed or Unsigned, Unipolar, Single-Ended Multiplexer Assignment, Analog Input Range of 2V s VIN s 4.
PAGE 23
PAGE 24
Physical Dimensions inches (millimeters) Dual-In-Line Package (M) Order Number ADC10154CIWM NS Package Number M24B Dual-In-Line Package (M) Order Number ADC10158CIWM NS Package Number M28B 24
PAGE 25
Physical Dimensions inches (millimeters) (Continued) Dual-In-Line Package (N) Order Number ADC10154CIN NS Package Number N24A 25
PAGE 26
ADC10154, ADC10158 10-Bit Plus Sign 4 ms ADCs with 4- or 8-Channel MUX, Track/Hold and Reference Physical Dimensions inches (millimeters) (Continued) Dual-In-Line Package (N) Order Number ADC10158BIN or ADC10158CIN NS Package Number N28B LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1.