Texas Instruments TL499ACPSR

Overview

TL499ACPSR from Texas Instruments is a dual-mode wide-range power-supply controller integrating an internal series-pass linear regulator and a step-up switching regulator. 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 input (SW REG IN2) from 1.1 V to 10 V, and operates across –20°C to +85°C for battery backup in microprocessor memory systems.

For engineers reviewing the TL499ACPSR datasheet, TL499ACPSR pinout, TL499ACPSR application, or TL499ACPSR equivalent, this page provides verified functional modes, validated pin functions, confirmed thermal metrics for SO-8 packaging, and real-world design constraints including minimum VO–VI2 differential voltage (1.9 V at 85°C) and RCL-dependent output current limits.

Technical Context

The TL499ACPSR operates in two mutually exclusive functional modes: linear regulation when SERIES IN1 is present (dropout voltage 1.8 V at 50 mA), and step-up switching regulation when SERIES IN1 is absent-using SW IN as the switching node and SW CURRENT CTRL to set peak inductor current via external resistor RCL (150 Ω to 1 kΩ). Internal reference voltage is 1.26 V ±60 mV with 5–10 mV/V temperature drift.

It requires no external rectifier diode, integrates startup circuitry, and uses REF pin feedback with RE1/RE2 resistive divider to set output voltage per VOUT = 1.26 × (1 + RE1/RE2). The device features separate signal ground (GND) and power ground (GND (PWR)) pins to minimize noise coupling between control and power paths.

Key Specifications

Pinout & Package

TL499ACPSR is housed in an 8-pin SO (PS) package measuring 6.20 mm × 5.30 mm, with lead finish NIPDAU and moisture sensitivity level (MSL) Level-1 (unlimited floor life at ≤30°C/60% RH).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2577-ADJ and TPS61088, TL499ACPSR uniquely integrates dual-input switchover, eliminating external logic or sequencing circuits-reducing BOM count and improving reliability in memory backup and industrial controller designs.

Availability

TL499ACPSR is available at Aetrix Electronics and suitable for microprocessor memory backup, battery-powered industrial controllers, and dual-supply voltage regulation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TL499ACPSR 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 delivering analog and embedded processing solutions, with leadership in power management ICs since the 1970s.

The TL499A product line was designed specifically for seamless AC-failure backup in memory systems and other mission-critical applications requiring automatic dual-input regulation without external supervision.

FAQ

What is the maximum output current achievable with TL499ACPSR in step-up mode?

The maximum output current in step-up mode depends on SW REG IN2 voltage, output voltage, and RCL value. With TL499ACPSR and RCL = 150 Ω, it delivers up to 65 mA at VO = 30 V and VI2 = 6 V (25°C). At higher temperatures or tighter VI2/VO differentials, current drops-e.g., 20 mA at VO = 30 V and VI2 = 1.1 V. Always consult Table 1 in the datasheet for exact derating.

Can TL499ACPSR operate without a battery or secondary input?

Yes-TL499ACPSR functions solely in series linear regulation mode when only SERIES IN1 is applied. In this configuration, SW REG IN2, SW IN, and SW CURRENT CTRL can remain unconnected or tied to appropriate bias points. Output regulation remains fully functional, with dropout voltage of 1.8 V at 50 mA and reference accuracy maintained.

What is the minimum VO – VI2 differential required for reliable TL499ACPSR switching operation at 85°C?

For TL499ACPSR operating at TA = 85°C, the minimum VO – VI2 differential is 1.9 V. This ensures sufficient headroom for the internal switching regulator to maintain regulation. At TA ≤ 70°C, the minimum is relaxed to 1.2 V. Operating below these thresholds risks output collapse or unstable switching behavior.

How does the SW CURRENT CTRL pin affect TL499ACPSR performance?

The SW CURRENT CTRL pin on TL499ACPSR accepts a resistor to ground (RCL) that directly sets peak inductor current: lower RCL values increase current limit (e.g., 150 Ω → ~500 mA switch current), while higher values reduce it (e.g., 1 kΩ → ~100 mA). This allows precise optimization of efficiency, inductor size, and thermal performance without modifying feedback or compensation networks.

Is TL499ACPSR pin-compatible with TL499ACP (PDIP-8)?

Yes-TL499ACPSR (SO-8) and TL499ACP (PDIP-8) share identical pinout, electrical specifications, and functional behavior. Both use the same 8-pin mapping (SERIES IN1, REF, SW REG IN2, etc.) and operate across –20°C to +85°C. Only package dimensions, thermal resistance (θJA = 110.7°C/W vs. 49.7°C/W), and assembly process differ.