Diodes Incorporated ZXLD1601H6TA

Overview

ZXLD1601H6TA from Diodes Incorporated (formerly Zetex Semiconductors) is a PFM-controlled inductive boost converter with integrated 30V NDMOS switch, internal current-sense resistor, and feedback divider. It delivers up to 28V output from 2.5–5.5V input, supports 250mA at 5V or 10mA at 28V, operates up to 1MHz, and achieves 85% typical efficiency in SC70-6 package for LCD/OLED bias applications.

For engineers reviewing the ZXLD1601H6TA datasheet, ZXLD1601H6TA pinout, ZXLD1601H6TA application, or ZXLD1601H6TA equivalent, key selection criteria include its true analog PWM-adjustable output via EN pin, internal 1.025V reference at FB, 120µs EN turn-off delay, 60µA quiescent current, and SC70-6 thermal/power constraints in portable power management designs.

Technical Context

The ZXLD1601H6TA operates in discontinuous conduction mode with self-oscillating PFM control, where peak inductor current (320mA typ) and fixed minimum off-time (350–500ns) govern switching frequency (600kHz typ at 28V/5mA). Its control loop maintains 1.025V at FB by comparing VSENSE against an internal reference through R1 (135kΩ) and R2 (3.45MΩ).

PWM-based output adjustment uses the EN pin as dual-function interface: above 10kHz, it enables continuous low-ripple analog-mode control (VOUT = D × VOUT(nom)); below 1kHz, it gates full device operation for average-voltage control. Internal 4kHz low-pass filter ensures stable duty-cycle-to-voltage conversion without external components.

Key Specifications

Pinout & Package

Supplied in low-profile SC70-6 package (2.1mm × 1.3mm × 0.9mm), optimized for space-constrained portable PCBs with minimal thermal mass.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar boost converter applications.

Compared with AP5727FDCG-7 and TPS61040DBVR, the ZXLD1601H6TA uniquely integrates FB divider, EN-pin PWM filtering, and gated/analog dual-mode control in SC70-6-reducing bill-of-materials and simplifying firmware-driven voltage adjustment in space-limited portable displays.

Availability

ZXLD1601H6TA is available at Aetrix Electronics and suitable for LCD/OLED bias, mobile phone camera flash, and digital camera backlight applications requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for ZXLD1601H6TA 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

Diodes Incorporated acquired Zetex Semiconductors in 2008 and continues to manufacture and support its high-performance analog and power management portfolio.

The ZXLD1601 belongs to Zetex's legacy portable power management product line, designed specifically for ultra-compact, low-quiescent-current DC-DC conversion in battery-powered consumer electronics.

FAQ

What is the minimum output voltage achievable with the ZXLD1601H6TA?

The minimum output voltage equals the input supply voltage (VIN), as the device cannot buck. When using PWM control on the EN pin, VOUT(AVG) scales linearly from VOUT(nom) down to VIN. For example, with nominal 28V output and 10% EN duty cycle, average output approaches 2.8V only if VIN ≥ 2.8V; otherwise, output clamps at VIN. External FB resistors can lower nominal output first to extend effective PWM range.

Can the ZXLD1601H6TA drive multiple parallel LEDs directly?

No-it regulates output voltage, not current, and lacks built-in LED current regulation or protection. To drive parallel LEDs, an external current-setting resistor or constant-current sink must be added in series with each LED string. The device's 250mA capability at 5V supports up to five 50mA strings only if total forward voltage remains ≤5V; higher VOUT reduces available current proportionally per the power constraint (P_OUT ≈ V_OUT × I_OUT ≤ 28V × 10mA).

How does the EN pin's 120µs turn-off delay affect PWM dimming design?

The 120µs delay ensures the device remains active briefly after EN goes low, preventing output collapse during high-frequency PWM dimming. For stable analog-mode control, EN frequency must exceed 10kHz so the delay occupies <1.2% of each period. At lower frequencies (e.g., 100Hz), the delay dominates, forcing gated-mode operation where output is fully on/off-increasing ripple but simplifying MCU timing requirements.

Why does the datasheet specify "R1 = 135kΩ" and "R2 = 3.45MΩ" but list different resistor values for 5V/12V outputs?

Those internal values set the default 26–28V output. External resistors shunt R1 and/or R2 to lower the effective divider ratio, thereby reducing VOUT according to VOUT = 1.025V × (R1∥R_ext1 + R2∥R_ext2) / (R1∥R_ext1). The table provides R_ext1 and R_ext2 values that, when placed across internal R1 and R2 respectively, yield target outputs-accounting for ±30% internal resistor tolerance and minimizing error from parallel resistance effects.