R1173H081D-T1-FE

Nisshinbo (formerly Ricoh) R1173H081D-T1-FE (0.8V fixed output)

Key Parameters

• Load regulation: Typical –3mV @ 1A
• Quiescent current: 60µA (typical), shutdown current 0.1µA
• Inrush current: Typical 500mA
• Input voltage range: 1.4V~6V
• PSRR: 70dB @ 1kHz
• Output accuracy: ±2% (0.8V output corresponds to 0.784V~0.816V)

Critical Limitations

• Dropout headroom: Maximum dropout voltage is 0.72V @ 1A; for 0.8V output, input must be ≥ 1.52V to maintain regulation at full load. The minimum 1.4V input is not usable at full load.
• Output capacitor: When Vout < 1.0V, COUT must be a 4.7µF tantalum capacitor (not replaceable with MLCC), and ESR specifications must be strictly followed.
• Thermal dissipation: SOT-89-5 package thermal resistance is about 150~180°C/W. For example, 3.3V→0.8V at 1A dissipates 2.5W, causing a temperature rise over 400°C, so continuous 1A output is impossible. The actual continuous current must be calculated based on the dropout voltage, typically limited to 300~500mA.
• Current limit parameter: The “Typ. 250mA” in the data sheet summary contradicts the 1A output capability; the actual current limit for this series is usually designed around 1.5A~2A, and the original full data sheet should be referenced.
• High-frequency PSRR: Attenuation capability drops significantly above 100kHz, requiring input capacitor filtering.

Suitable Applications

• Low dropout (e.g., 1.5V→0.8V), average load < 500mA
• Consumer/industrial equipment with high load regulation requirements and stable input voltage

Unsuitable Applications

• High dropout (e.g., 5V→0.8V) under heavy load
• Applications requiring an all-ceramic capacitor solution
• Output accuracy requirement < ±1.5%
• Ambient temperature near 85°C with continuous full load

Selection Comparison Reference

• If dropout < 0.5V and average current < 400mA, this device is reliable; otherwise, consider a DC-DC converter or a larger-package LDO.
• The ±2% accuracy is inferior to mainstream ±1%/±0.5% LDOs; when used for FPGA/ASIC core power (typically requiring within ±3%), margin must be verified.
• The mandatory tantalum capacitor requirement is incompatible with ceramic capacitor solutions; system capacitor strategy should be considered when comparing with competitors.
• Thermal performance limitations make it unsuitable for high-power scenarios; among similar 1A LDOs, package and thermal resistance differences should be prioritized in evaluation.