Analog Devices Inc. LTC1159CG-5#PBF

Overview

LTC1159CG-5#PBF from Analog Devices (formerly Linear Technology) is a fixed-output 5V synchronous step-down switching regulator controller driving external complementary MOSFETs. It operates from 4V to 40V input, delivers up to 2A output current, achieves up to 95% efficiency, maintains regulation with 100% duty cycle, and features Burst Mode™ for ultra-low 300µA standby current. It is used in battery-powered portable instruments and telecom power supplies.

For engineers reviewing the LTC1159CG-5#PBF datasheet, LTC1159CG-5#PBF pinout, LTC1159CG-5#PBF application, or LTC1159CG-5#PBF equivalent, key selection criteria include its constant off-time current-mode architecture, EXTVCC-driven efficiency optimization, programmable current limit via R_SENSE, -40°C to 85°C operating range, and SSOP-20 package compatibility with industrial and avionics power designs.

Technical Context

The LTC1159CG-5#PBF implements a constant off-time current-mode control architecture with adaptive non-overlap gate drives, enabling excellent line and load transient response. Its internal 4.5V linear regulator powers startup circuits, while EXTVCC allows driver sections to be powered from the regulated output-reducing quiescent current and improving high-input-voltage efficiency.

Burst Mode™ operation activates below ~15% of maximum load current, reducing supply current to 300µA while maintaining regulation; shutdown draws only 20µA. The device uses separate SHDN1 (control-only disable) and SHDN2 (master VCC + control shutdown) pins, and supports short-circuit protection via automatic t_OFF extension.

Key Specifications

Pinout & Package

Package: 20-lead plastic SSOP (G package), 0.65mm pitch, JEDEC MO-153 compliant, θ_JA = 135°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck controller applications.

Compared with LTC1149CS-5#PBF, LTC1159CG-5#PBF adds EXTVCC efficiency optimization and differential current sensing, while LM5116MH/NOPB trades fixed-output simplicity for wide-input flexibility and higher minimum load current - making LTC1159CG-5#PBF optimal for 4–40V, 5V, low-I_Q applications.

Availability

LTC1159CG-5#PBF is available at Aetrix Electronics and suitable for portable instrumentation, avionics power distribution, and industrial telecom power supplies requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +85°C performance.

Supply support for LTC1159CG-5#PBF 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

Analog Devices (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision, industrial, automotive, and communications markets.

The LTC1159 series was designed as a family of synchronous buck controllers optimized for high-efficiency, wide-input-voltage DC-DC conversion in portable and ruggedized systems - emphasizing low quiescent current, robust protection, and ease of layout with integrated gate drive logic.

FAQ

What is the output voltage tolerance of the LTC1159CG-5#PBF under full load and temperature?

The LTC1159CG-5#PBF delivers a fixed 5V output with ±2% tolerance (4.90V to 5.20V) across 5mA–2A load, 4V–40V input, and -40°C to +85°C ambient. This specification is guaranteed over the full operating temperature range (denoted by 'G' in the datasheet) and includes line, load, and thermal effects - eliminating need for external feedback calibration.

Does the LTC1159CG-5#PBF require an external feedback resistor network?

No, the LTC1159CG-5#PBF does not require an external feedback resistor network. It integrates an internal resistive divider referenced to the SENSE− pin, setting the output to 5.05V (typical). Only the adjustable LTC1159 variant uses the VFB pin with external resistors; the -5 suffix denotes factory-trimmed fixed output.

How does the EXTVCC pin improve efficiency in the LTC1159CG-5#PBF?

The EXTVCC pin allows the LTC1159CG-5#PBF's gate drivers and control circuitry to be powered from the regulated 5V output instead of the high-input VIN rail. At 40V input, this reduces driver supply current losses by >60%, contributing directly to the 95% peak efficiency - confirmed in Figure 1 (LTC1159•TA01) and Applications Information section.

What is the purpose of the dual shutdown pins (SHDN1 and SHDN2) on the LTC1159CG-5#PBF?

SHDN1 disables only the PWM control logic while keeping VCC active - useful for controlled soft-start or sequencing. SHDN2 is the master shutdown that cuts VCC and all circuitry, reducing total current to 20µA. This dual-pin architecture enables precise power-state management in multi-rail systems where partial or full shutdown is required.

Can the LTC1159CG-5#PBF operate with 100% duty cycle, and what design benefit does that provide?

Yes, the LTC1159CG-5#PBF supports true 100% duty cycle operation, allowing VOUT to track VIN down to within the dropout voltage of the external P-MOSFET. This enables regulation during severe input brownouts (e.g., 4V input → 5V output impossible, but 5.5V input → 5V output sustained), critical for automotive and aerospace systems with unstable input sources.