Texas Instruments TL499ACP

Overview

TL499ACP from Texas Instruments is a dual-mode wide-range power-supply controller integrating both series linear and step-up switching regulation in a single 8-pin PDIP package. It delivers adjustable regulated output from 2.9 V to 30 V, supports primary input (SERIES IN1) from 4.5 V to 32 V and secondary battery input (SW REG IN2) from 1.1 V to 10 V, and operates across –20°C to +85°C - enabling seamless backup power switchover in microprocessor memory systems.

For engineers reviewing the TL499ACP datasheet, TL499ACP pinout, TL499ACP application, or TL499ACP equivalent, key selection considerations include its dual-input architecture, externally set switching current via SW CURRENT CTRL pin, dropout voltage of 1.8 V at 50 mA, internal 1.26 V reference, and absence of external rectifier requirement in step-up mode.

Technical Context

The TL499ACP operates in two mutually exclusive functional modes: linear regulation when SERIES IN1 is present (VI1 ≥ VO + 1.8 V), and step-up switching regulation when SERIES IN1 is absent and SW REG IN2 supplies power. Its internal power switch drives an external inductor at variable duty cycle controlled by feedback from the REF pin and current sensing through the SW CURRENT CTRL resistor.

Regulation accuracy depends on the internal 1.26 V reference (±5 mV typical), temperature drift of ≤10 mV/V, and output voltage deviation ≤30 mV/V between modes. The device requires no external rectifier in step-up mode due to integrated blocking-diode control, and supports continuous output current up to 100 mA in series mode and up to 100 mA in switching mode depending on RCL and voltage differentials.

Key Specifications

Pinout & Package

TL499ACP uses an 8-pin plastic dual in-line package (PDIP) with body size 9.81 mm × 6.35 mm and through-hole mounting. Pin 1 is located at the left end of the top row when viewed from the top with notch or dot oriented upward.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-mode power-supply controller applications.

Compared with LM2577-ADJ and TPS63020DSJR, TL499ACP uniquely integrates automatic dual-mode regulation in one die, eliminating external switchover components while preserving low-noise linear performance - making it optimal for memory backup and mixed-source industrial supplies where reliability and simplicity are paramount.

Availability

TL499ACP is available at Aetrix Electronics and suitable for microprocessor memory backup, battery-backed industrial controllers, dual-supply voltage regulation, and low-voltage boosting applications requiring stable component supply across extended product lifecycles.

Supply support for TL499ACP 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 company founded in 1930, specializing in analog, embedded processing, and power management technologies with broad industrial and automotive design-in leadership.

The TL499A product line was designed specifically for high-reliability, dual-input power management in memory retention and backup systems - emphasizing seamless switchover, wide input flexibility, and minimal external component count.

FAQ

What is the maximum output current capability of TL499ACP in series regulation mode?

The TL499ACP supports up to 100 mA continuous output current in series regulation mode, verified under recommended operating conditions (VI1 = 15 V, VO = 9 V, TA = 25°C). This rating assumes adequate heatsinking and remains valid across the full –20°C to +85°C temperature range. Exceeding 100 mA risks thermal shutdown or reduced regulation accuracy due to internal power dissipation limits.

Can TL499ACP operate with a 1.5 V alkaline battery as the SW REG IN2 source?

Yes, TL499ACP supports SW REG IN2 input voltages from 1.1 V to 10 V, making 1.5 V alkaline batteries fully compatible. At VI2 = 1.5 V and VO = 9 V, the device delivers up to 15 mA output current with RCL = 150 Ω per Table 1 in the datasheet. Performance scales with RCL value and temperature - lower RCL increases current but raises thermal load.

How does TL499ACP handle switchover between SERIES IN1 and SW REG IN2 inputs?

TL499ACP performs automatic, seamless switchover without external control: when SERIES IN1 drops below VO + dropout voltage (~1.8 V), the device disables the series pass element and activates the step-up switching regulator using SW REG IN2. No external logic or delay circuits are needed - transition occurs within microseconds and causes <30 mV/V output deviation, preserving system stability.

What is the purpose of the SW CURRENT CTRL pin on TL499ACP?

The SW CURRENT CTRL pin (Pin 4) accepts an external resistor to ground that directly programs the peak current limit of the internal power switch. A 150 Ω resistor sets ~500 mA peak current; increasing resistance reduces current. This allows designers to balance inductor size, efficiency, and transient response - critical for optimizing boost converter performance in battery-backed applications.

Is TL499ACP RoHS-compliant and lead-free?

Yes, TL499ACP is RoHS-compliant and features NiPdAu (NIPDAU) lead finish, as confirmed in TI's official packaging addendum. It meets JEDEC J-STD-020 moisture sensitivity Level-1 for the SO variant, though the PDIP version (TL499ACP) has N/A MSL rating due to its through-hole construction. Full compliance documentation is available in TI's official orderable part database.