Texas Instruments LM4140CCMX-1.2

Overview

LM4140CCMX-1.2 from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference delivering 1.25 V output with ±0.1% initial accuracy, 10 ppm/°C temperature coefficient (C grade), 20 mV typical dropout at 1 mA, and 230 µA typical supply current. It features an enable pin for power management and is used in precision ADC/DAC biasing, portable instrumentation, and battery-powered data acquisition systems.

For engineers reviewing the LM4140CCMX-1.2 datasheet, LM4140CCMX-1.2 pinout, LM4140CCMX-1.2 application, or LM4140CCMX-1.2 equivalent, key selection considerations include its 1.25 V output voltage, C-grade 10 ppm/°C drift, SOIC-8 package, enable-controlled shutdown (<1 µA), and required 1 µF output capacitor for stability.

Technical Context

The LM4140CCMX-1.2 employs EEPROM-trimmed CMOS DACs for curvature-corrected temperature compensation and output voltage trimming-enabling sub-bandgap 1.25 V output with higher resolution than conventional bandgap references. Its P-channel pass transistor architecture supports operation down to VIN = VREF + 20 mV (typical) and enables fast turn-on (<200 µs).

It operates over 0°C to 70°C, requires no input capacitor but mandates a 1 µF output capacitor (±20% tolerance, ESR 0.1–10 Ω), and uses internal charge-discharge circuitry during enable transitions to prevent output capacitor voltage overshoot or undershoot.

Key Specifications

Pinout & Package

LM4140CCMX-1.2 is housed in an 8-pin SOIC package (4.90 mm × 3.91 mm body size) with exposed pad not electrically connected. Pin 5 is NC and must remain unconnected; pins 1, 4, 7, and 8 are all ground terminals and must be tied to system GND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage reference applications.

Compared with REF3012AIDBZR and ADR3412ARJZ-R7, the LM4140CCMX-1.2 uniquely delivers 1.25 V output with C-grade 10 ppm/°C drift, four ground pins for superior PSRR, and 8 mA drive - making it optimal for mid-power, high-accuracy industrial and medical systems requiring exact 1.25 V scaling.

Availability

LM4140CCMX-1.2 is available at Aetrix Electronics and suitable for portable instrumentation, precision data acquisition, and battery-powered medical devices requiring stable component supply, long-term calibration retention, and guaranteed lifecycle continuity.

Supply support for LM4140CCMX-1.2 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and digital signal technologies, with decades of leadership in precision analog ICs.

The LM4140 product line was designed specifically for high-accuracy, low-drift voltage references in portable, battery-operated, and industrial measurement systems - emphasizing sub-bandgap outputs, EEPROM-based trimming, and robust enable-controlled operation.

FAQ

What is the minimum input voltage required for stable operation of the LM4140CCMX-1.2?

The LM4140CCMX-1.2 requires a minimum input voltage of VREF + 20 mV (i.e., 1.27 V) at 1 mA load for stable regulation, per datasheet Section 6.5. At higher loads or temperature extremes, dropout increases up to 45 mV (0°C–70°C). Operation below 1.8 V is not recommended due to degraded line regulation and increased tempco uncertainty.

Does the LM4140CCMX-1.2 require an output capacitor, and what type is recommended?

Yes - the LM4140CCMX-1.2 requires a 1 µF output capacitor connected between VREF and GND for loop stability and transient response. TI validates solid tantalum (e.g., Kemet T491A105M010AS) and multilayer ceramic capacitors (e.g., Murata GRM42-6Y5V225Z16) with ESR between 0.1 Ω and 10 Ω. Aluminum electrolytics are discouraged due to ESR drift at low temperatures.

Can the LM4140CCMX-1.2 sink current, or is it sourcing-only?

The LM4140CCMX-1.2 is a series voltage reference with sourcing-only output capability - it can deliver up to 8 mA to a load tied between VREF and GND. It cannot actively sink current. If reverse current flow is possible (e.g., from external circuitry pulling VREF low), the internal P-channel pass transistor's body diode may conduct, but sustained sink current >50 mA risks damage.

How does the enable pin function on the LM4140CCMX-1.2, and what happens during shutdown?

The LM4140CCMX-1.2 enable pin (Pin 3) is active-high: driving it ≥0.8×VIN turns the device on; pulling it ≤0.4 V disables output and reduces supply current to ≤1 µA. During shutdown, internal circuitry actively discharges the output capacitor to GND within microseconds - preventing residual voltage holdup and ensuring clean power-down sequencing.

What is the meaning of "C grade" in LM4140CCMX-1.2, and how does it differ from A or B grades?

"C grade" in LM4140CCMX-1.2 denotes the temperature coefficient specification: 10 ppm/°C (max) over 0°C–70°C, versus 3 ppm/°C (A grade) or 6 ppm/°C (B grade). Initial accuracy remains ±0.1% across all grades. The "C" suffix also indicates the 1.25 V output option and SOIC-8 packaging - distinct from LM4140AMX-1.2 (A grade) or LM4140BMX-1.2 (B grade).