Overview
The LM285DR-1.2 is a micropower, two-terminal, band-gap voltage reference produced by Texas Instruments. This device is part of the LMx85-1.2 series, which includes the LM285-1.2, LM385-1.2, and LM385B-1.2. It operates over a wide current range, making it suitable for various applications requiring stable voltage references.
The LM285DR-1.2 is designed to provide a stable 1.235V reference voltage with low noise and long-term stability. It features exceptionally low dynamic impedance and good temperature stability, making it tolerant of capacitive loading and easy to use in most reference applications.
Although the LM285DR-1.2 is listed as obsolete, its specifications and features remain relevant for understanding its capabilities and potential uses in legacy systems or for educational purposes.
Key Specifications
| Parameter | LM285-1.2 | LM385-1.2 | LM385B-1.2 |
|---|---|---|---|
| Operating Current Range | 10 μA to 20 mA | 15 μA to 20 mA | 15 μA to 20 mA |
| Reference Voltage (VZ) | 1.223 to 1.247 V | 1.21 to 1.26 V | 1.223 to 1.247 V |
| Initial Voltage Tolerance | 1% and 2% | 1% and 2% | 1% and 2% |
| Reference Impedance (ZZ) | 1.5 Ω MAX over full temperature range | 1.5 Ω MAX over full temperature range | 1.5 Ω MAX over full temperature range |
| Operating Temperature Range | -40°C to 85°C | 0°C to 70°C | 0°C to 70°C |
| Minimum Reference Current (IZ,min) | 10 μA | 15 μA | 15 μA |
| Broadband Noise Voltage (Vn) | 60 µV (10 Hz to 10 kHz) | 60 µV (10 Hz to 10 kHz) | 60 µV (10 Hz to 10 kHz) |
Key Features
- Operating current range from 10 μA to 20 mA, making it suitable for micropower applications.
- Exceptionally low dynamic impedance and good temperature stability.
- Tight voltage tolerance due to on-chip trimming.
- Low noise and long-term stability of the band-gap reference.
- High tolerance to capacitive loading, making it easier to use in various reference applications.
- Very low power consumption, ideal for battery-operated systems.
- Interchangeable with industry-standard voltage references.
Applications
- Portable meter references and test instruments.
- Battery-operated systems and current-loop instrumentation.
- Panel meters and general-purpose analog circuitry.
- Power supplies and current-sensing circuits.
- Amplifiers and regulators requiring stable voltage references.
Q & A
- What is the operating current range of the LM285DR-1.2?
The operating current range of the LM285DR-1.2 is from 10 μA to 20 mA.
- What is the reference voltage of the LM285DR-1.2?
The reference voltage of the LM285DR-1.2 is typically 1.235V, with a tolerance range of 1.223V to 1.247V.
- What is the minimum reference current required for the LM285DR-1.2?
The minimum reference current required for the LM285DR-1.2 is 10 μA.
- What is the operating temperature range of the LM285DR-1.2?
The operating temperature range of the LM285DR-1.2 is -40°C to 85°C.
- Is the LM285DR-1.2 tolerant of capacitive loading?
- What are some typical applications of the LM285DR-1.2?
Typical applications include portable meter references, battery-operated systems, current-loop instrumentation, and general-purpose analog circuitry.
- What is the broadband noise voltage of the LM285DR-1.2?
The broadband noise voltage of the LM285DR-1.2 is 60 µV over the frequency range of 10 Hz to 10 kHz.
- Is the LM285DR-1.2 still in production?
No, the LM285DR-1.2 is listed as obsolete and is no longer in production.
- What packages are available for the LM285-1.2 series?
The LM285-1.2 series is available in various packages including SOIC, SOP, TSSOP, and TO-92.
- How should the LM285DR-1.2 be laid out on a PCB?
Best practices include using a low-ESR bypass capacitor on the cathode pin, decoupling other active devices, using a solid ground plane, and placing external components close to the device to prevent parasitic errors.
