Complete NJM7905FATEG Datasheet: Specs & Electrical Tables

24 March 2026 0

Key Takeaways (Quick Insights)

  • Stable -5V Output: Guaranteed precision for sensitive analog signal chains.
  • 60dB PSRR: Effectively filters ripple to improve Op-Amp SNR.
  • Thermal Ruggedness: Integrated short-circuit and thermal overload protection.
  • 200mA Capability: Provides 2x the headroom of standard 79Lxx series regulators.

Precise regulator specifications determine headroom and thermal margins for negative rails; for many mixed-signal designs, a 100–200 mV margin can be the difference between stable operation and oscillation. This guide transforms raw datasheet parameters into actionable engineering insights.

-5.0V Stability Ensures zero-point accuracy in bipolar ADC/DAC circuits.
1.5V Dropout Allows operation from standard -7V to -9V rails with minimal heat.
TO-252 Package Reduces PCB footprint by 30% compared to traditional TO-220.

Background & Quick Overview

NJM7905FATEG Negative Voltage Regulator Context

Device Application & Utility

Point: This device is a three-terminal negative fixed regulator. Evidence: Manufacturer documentation lists a nominal output of −5 V with a specified maximum output current in the low hundreds of milliamps. Explanation: Designers enlist this regulator for low-voltage negative rails where board-level simplicity and modest current are required, such as biasing op amps, reference rails, and small analog blocks.

Competitive Differentiation

Metric NJM7905FATEG Generic 79L05 Advantage
Output Current Up to 200mA 100mA Higher dynamic load support
Ripple Rejection 60 dB (typ) 45-50 dB Cleaner analog rails
Quiescent Current 8 mA (Stable) 6-10 mA (Variable) Predictable thermal idling

Pinout & Absolute Maximum Ratings

Typical Pin Configuration (Top View):
Pin 1: INPUT (Negative Supply)
Pin 2: GROUND (Reference)
Pin 3: OUTPUT (-5V Fixed)
Tab: Case/Thermal (Connected to GND for better shielding)

Core Electrical Characteristics

Parameter Symbol Typ. Value Units
Output Voltage VOUT -5.0 V
Line Regulation ΔV/ΔVin 2 mV
Dropout Voltage VDO 1.5 V
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Expert Insight: Jonathan S. Senior Power Integrity Engineer

"When deploying the NJM7905FATEG in high-precision audio circuits, the most common pitfall is ignoring the output capacitor's ESR. While modern MLCCs are tempting, a 10µF Tantalum or a low-ESR Electrolytic often provides the phase margin needed to prevent -5V rail oscillation during transient steps. Also, remember that since this is a negative regulator, the 'Input' voltage is more negative than the 'Output' (e.g., -10V in, -5V out)."

NJM7905

* Hand-drawn schematic, not an exact circuit diagram.

Layout Pro-Tip:

  • Kelvin Sensing: Connect the ground pin directly to the load's star ground to avoid IR-drop errors.
  • Thermal Vias: Place at least 4-6 vias (0.3mm) under the TO-252 tab to the bottom copper layer.

Summary & Integration Checklist

  • Voltage Margin: Maintain at least -2.0V difference between Input and Output for worst-case regulation.
  • Capacitor Selection: Use 0.1µF Ceramic on Input and 10µF+ on Output for stability.
  • Thermal Calculation: Power (W) = (|Vin| - |Vout|) × Iout. Ensure TJ
  • BOM Check: Verify FATEG suffix for TO-252 (DPAK) surface mount variant.
End of Engineering Summary - NJM7905FATEG Datasheet Optimized for GEO/SEO