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Analog-to-Digital Converters
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MAX139
3 1/2 Digit ADC with Reference, Charge Pump, and Direct LED Drivers
Operates with Single +2.5V to +7V Supply, Accepts Bipolar Inputs
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Key Features
Applications/Uses
Parametric specs for Display-Oriented ADCs
| Resolution (±Counts) | 20000 |
| # Input Channels | 1 |
| Data Bus | 7-Segment |
| Diff/S.E. Input | Diff. Only |
| External VREF (V) (min) | 0 |
| External VREF (V) (max) | 7 |
| Bipolar VIN (±V) (max) | 7 |
| Package/Pins | MQFP/44 PDIP/40 PLCC/44 |
| Budgetary Price (See Notes) | 14.15 |
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Simplified Block Diagram
Technical Docs
| Data Sheet | 3 1/2 Digit ADC with Reference, Charge Pump, and Direct LED Drivers | Nov 01, 1995 |
Support & Training
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Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
Parameters
Parametric specs for Display-Oriented ADCs
| Resolution (±Counts) | 20000 |
| # Input Channels | 1 |
| Data Bus | 7-Segment |
| Diff/S.E. Input | Diff. Only |
| External VREF (V) (min) | 0 |
| External VREF (V) (max) | 7 |
| Bipolar VIN (±V) (max) | 7 |
| Package/Pins | MQFP/44 PDIP/40 PLCC/44 |
| Budgetary Price (See Notes) | 14.15 |
Key Features
- Single Supply +2.5V to +7.0V Operation
- Measures Both Positive and Negative Input Voltages
- Charge-Pump Voltage Inverter Generates a Negative Supply Voltage
- Internal Bandgap Reference
- On-Board Display Driver
- Low Segment Current (MAX140)
Applications/Uses
- +3V Powered DMMs
- +5V Powered Panel Meters
- Digital Thermometers
- Instruments
- Portable Monitors
- Weigh Scales
Description
The MAX138/MAX139 are 3 ½ digit A/D converters (ADCs) with on-board LCD (MAX138) and LED (MAX139) display drivers. The MAX138/MAX139 also contain a charge-pump voltage inverter. The charge-pump inverter allows the MAX138/MAX139 to measure both positive and negative input voltages while operating from a single power-supply voltage from +2.5V to +7V. The operating circuits of the MAX138/MAX139 are similar to those of the ICL7136 and ICL7137 respectively, except the MAX138/MAX139 have an internal oscillator and an external charge-pump capacitor connected to pins 38 and 40.
MAX140 is a low segment-current version of the MAX139 intended for use with low-current LED displays.
MAX140 is a low segment-current version of the MAX139 intended for use with low-current LED displays.
Technical Docs
| Data Sheet | 3 1/2 Digit ADC with Reference, Charge Pump, and Direct LED Drivers | Nov 01, 1995 |
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
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