STMicroelectronics ST755CD-TR

Overview

ST755CD-TR from STMicroelectronics is an adjustable inverting negative-output current-mode PWM DC-DC regulator with integrated P-channel Power MOSFET, delivering up to 275mA output current at -5V (25°C), 1.25V internal reference voltage, 160kHz fixed-frequency oscillator, and shutdown quiescent current of 10µA. It operates from 2.7V–11V input to generate regulated negative outputs (e.g., -5V) for low-noise analog supply rails in portable instrumentation.

For engineers reviewing the ST755CD-TR datasheet, ST755CD-TR pinout, ST755CD-TR application, or ST755CD-TR equivalent, key selection criteria include its inverting topology, SO-8 package thermal resistance (160°C/W), guaranteed 200mA load capability at 0°C–70°C, soft-start control via external capacitor, and mixed bipolar-CMOS process enabling low-jitter operation and high temperature stability.

Technical Context

The ST755CD-TR implements current-mode PWM control with an internal error amplifier comparing feedback voltage against a precise 1.25V reference, driving a comparator that modulates the 160kHz oscillator to regulate LX switch duty cycle. Output polarity inversion is achieved through synchronous inductive energy transfer to a negative rail referenced to GND.

It integrates a 0.7Ω R_DS(on) P-channel Power MOSFET on die, supports external compensation via CC pin (7.5kΩ impedance), and uses soft-start (SS) pin voltage to linearly limit peak switch current during startup. Shutdown is logic-compatible: SHDN = VCC enables operation; SHDN = GND reduces supply current to 10µA.

Key Specifications

Pinout & Package

ST755CD-TR is housed in a standard SO-8 (Small Outline-8) package with exposed pad not electrically connected, rated for 470mW continuous power dissipation at T_A = 70°C (R_thJA = 160°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar inverting negative-output DC-DC regulator applications.

Compared with LM2662CMX/NOPB and MAX764CSA+, the ST755CD-TR delivers optimal balance of integration (internal MOSFET), noise performance (fixed 160kHz vs. variable), and guaranteed 200mA load capability in a drop-in SO-8 footprint - making it ideal for mid-power analog subsystems where layout simplicity and thermal predictability are prioritized.

Availability

ST755CD-TR is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition transmitters, test equipment analog front-ends, and automotive infotainment audio subsystems requiring stable component supply and long-term obsolescence planning.

Supply support for ST755CD-TR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, power, and analog applications since 1987.

The ST755 belongs to ST's legacy analog power management portfolio, engineered specifically for compact, low-noise inverting DC-DC conversion in space-constrained portable and industrial systems where integrated MOSFETs and predictable thermal behavior are essential.

FAQ

What is the maximum allowable input-to-output differential voltage for ST755CD-TR?

The absolute maximum input-to-output differential voltage is constrained by V_CC + |V_O| < 12.7V per datasheet Section 3. This means at V_CC = 11V, the most negative output allowed is -1.6V; at V_CC = 4.5V, output may reach -8.2V. Exceeding this limit risks damage to the internal LX switch and must be enforced in design.

Can ST755CD-TR generate -12V output from a 9V input?

No. With V_CC = 9V, the maximum |V_O| is limited to 3.7V (since 9 + 3.7 = 12.7V). Attempting -12V would violate the V_CC + |V_O| < 12.7V constraint and likely destroy the device. For -12V generation, use a controller like MAX764 with external high-voltage MOSFET.

How is output voltage set, and what tolerance does the feedback network introduce?

Output voltage is set by a resistor divider (R3–R4) from VO to VREF (1.25V), using V_O = –V_REF × (1 + R3/R4). The 1.25V reference has ±3% initial tolerance and 50ppm/°C drift. Using 1% resistors introduces ≤1.5% additional error, resulting in total output tolerance of approximately ±4.5% over temperature.

Is ST755CD-TR still recommended for new designs given its obsolete status?

While marked "Obsolete Product(s)" in ST's documentation, ST755CD-TR remains actively stocked and supported by Aetrix Electronics with full traceable sourcing and lifecycle coordination. Its proven reliability, SO-8 compatibility, and absence of known field failures make it viable for cost-sensitive, non-automotive, non-safety-critical designs where long-term supply assurance is managed via inventory planning.