PMIC - Voltage Reference

Part Number	Description / PDF	Quantity
LM385BZ-1.2RAG Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 1% TO92-3	336
KA431SMFTF Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 2% SOT23F-3	8610
CAT102TDI-GT3 Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 17.4V 1% TSOT23-5	365142000
LM431BIZX Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 1% TO92-3	610
NCP431BISNT1G Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 0.5% SOT23-3	20267
LM431AIZ Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 2% TO92-3	120000
NCP431AILPRAG Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 1% TO92	196614000
TL431ACDR2G Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 1% 8SOIC	7807
TL431BVDMR2G Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 0.4% MICRO8	2706
NCP431AISNT1G Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 1% SOT23-3	134
LM431SAIMFX Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 2% SOT23F-3	2500
NCV431BVDMR2G Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 0.4% MICRO8	2364
TL431CLPRAG Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 2.2% TO92-3	214
LM431SACMFX Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 2% SOT23F-3	2147483647
SC431ILPRAG Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 2.2% TO92	0
LM285Z-1.2G Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 1% TO92-3	98
LM385Z-1.2RPG Sanyo Semiconductor/ON Semiconductor	IC VREF SHNT -2.4%/+2.01% TO92-3	1930
TLV431BSN1T1G Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 16V 0.5% SOT23-3	2147483647
LM431SCCM32X Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 36V 0.5% SOT23-3	5156
TLV431ASNT1G Sanyo Semiconductor/ON Semiconductor	IC VREF SHUNT 16V 1% 5TSOP	1513

PMIC - Voltage Reference

1. Overview

Voltage references are precision analog circuits that generate stable and accurate DC voltage levels. As critical components in Power Management Integrated Circuits (PMICs), they serve as calibration standards for analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and power monitoring systems. Their stability against temperature variations, process shifts, and supply voltage fluctuations ensures measurement accuracy and system reliability in modern electronics.

2. Main Types and Functional Classification

Type	Functional Features	Application Examples
Bandgap Reference	Temperature-compensated design using bipolar transistor characteristics	General-purpose ADC/DAC calibration
Zener Reference	High-voltage stability through reverse breakdown characteristics	Industrial power supplies, test equipment
LDO Voltage Reference	Low dropout voltage with high PSRR performance	Battery-powered devices, portable instruments
High-Precision Reference	Sub-0.1% initial accuracy with ppm-level temperature drift	Medical imaging systems, precision sensors
Programmable Reference	Digital control of output voltage via I2C/SPI interfaces	Adaptive power systems, FPGA voltage scaling

3. Structure and Composition

Typical voltage reference architecture includes: - Primary reference source (bandgap or Zener diode) - Operational amplifier for voltage buffering - Temperature compensation circuitry - Output driver stage - Protective elements (ESD protection, current limiting) Fabricated using CMOS/BiCMOS processes, housed in SC70, SOT23, or TSSOP packages with 3-8 pins. Advanced designs integrate digital calibration registers and thermal shutdown functions.

4. Key Technical Specifications

Parameter	Description	Importance
Initial Accuracy	Voltage deviation at 25 C ( 0.02% to 1%)	Determines system calibration baseline
Temperature Coefficient	Drift rate over temperature range (1-100ppm/ C)	Affects measurement stability
Output Noise	RMS noise voltage in 0.1-10Hz band (5 V to 100 V)	Impacts ADC/DAC resolution
Load Regulation	Voltage change with load current (0.01%/mA)	Ensures stability under dynamic loads
Line Regulation	Voltage change with supply voltage (0.05%/V)	Maintains accuracy with supply variations

5. Application Areas

Communication: 5G base stations, optical transceivers, RF test equipment
Consumer: Smartphones, wearables, battery management systems
Industrial: Process control sensors, PLC modules, precision instrumentation
Automotive: Battery management systems (BMS), ADAS sensors, engine controllers
Medical: MRI systems, portable diagnostic devices, patient monitors

6. Leading Manufacturers and Products

Manufacturer	Product Series	Key Features
TI	LM4040/LM4050	0.1% accuracy, 50ppm/ C tempco, 50mA output
Analog Devices	ADR45xx	0.02% initial accuracy, 3ppm/ C drift
Maxim Integrated	MAX6126	Series voltage reference with enable pin
STMicroelectronics	LN3480	Low-power consumption (380nA IQ)
ON Semiconductor	NCP100	Cost-effective solution for 12-bit ADCs

7. Selection Guidelines

Key selection criteria: - Required accuracy class (0.02% vs 1%) - Operating temperature range (-55 C to +125 C) - Power supply constraints (voltage headroom, quiescent current) - Package size and thermal dissipation capability - Long-term stability requirements (aging effects) - Cost vs performance trade-offs (e.g., programmable vs fixed) Example: For a 16-bit industrial ADC system, select a reference with <5ppm/ C tempco and <1 Vpp noise.

8. Industry Trends

Nanometer process integration enabling sub-1V references
Development of chopper-stabilized references for ultra-low drift
Increase in digital programmable references with I2C interfaces
Advancements in radiation-hardened references for aerospace
Reduced package sizes (0.65mm x 1.0mm WLCSP)
AI-enhanced self-calibration algorithms in smart references