Power Management ICs

18V Input, 600 mA Synchronous Step-Down Switching Regulator S-8590AC/8590AD/8591AC/8591AD Series

Oscillation frequency: 2.2 MHz typ. products | 400 kHz typ. products

The S-8590/8591 Series is a step-down switching regulator developed using high withstand voltage CMOS process technologies.
This IC has high maximum operation voltage of 18 V and maintains high-accuracy FB pin voltage at ±1.5%. As suitable packages for high-density mounting, such as small-sized HSNT-6(2025), are adopted, this IC contributes to miniaturization of electronic equipment.
PWM control (S-8590 Series) or PWM / PFM switching control (S-8591 Series) can be selected as an option.
Since the S-8591 Series, which features PWM / PFM switching control, operates with PWM control under heavy load and automatically switches to PFM control under light load, it achieves high-efficiency operation in accordance with the device's status. Furthermore, our distinctive PWM / PFM switching control technology suppresses the ripple voltage to be generated in VOUT while PFM control is in operation.
Since the S-8590/8591 Series has the built-in synchronous circuit, it achieves high efficiency easier compared with conventional step-down switching regulators. In addition, it has the built-in overcurrent protection circuit which protects the IC and coils from excessive load current as well as a thermal shutdown circuit which prevents damage from heat generation.


Input voltage
4.0 V to 18.0 V
Output voltage (externally set)
2.5 V to 12.0 V
Output current
600 mA
FB pin voltage accuracy
Oscillation frequency
400 kHz typ.
Overcurrent protection function
1.2 A typ. (pulse-by-pulse method)
Thermal shutdown function
170°C typ. (detection temperature)
Short-circuit protection function
Hiccup control, Latch control
100% duty cycle operation
Soft-start function
5.8 ms typ.
Under voltage lockout function (UVLO)
3.35 V typ. (detection voltage)
Input and output capacitors
Ceramic capacitor compatible
Operation temperature range
Ta = −40°C to +85°C
Lead-free (Sn 100%), halogen-free


  • Constant-voltage power supply for industrial equipment
  • Constant-voltage power supply for home electric appliance

Parts List

  • U(Ux), S and G at the end of the product name of ABLIC Inc. were used to indicate different material specifications as “environmental code”,
    however, these have now been unified into “lead-free and halogen-free” and are identical in terms of environmental quality.
  • Note: Lead-free plating other than 100% Sn is applied to some limited old products, therefore, please contact our sales representatives for details.
  • These descriptions may be different from the actual product name and parameter.
    Please confirm the product name and specifications with the data sheet again.
  • The information herein is subject to change without notice.