PRELIMINARY INFORMATION LOW-DROPOUT REGULATORS — HIGH EFFICIENCY OUT BYPASS OR ADJ* (subject to change without notice) June 25, 1999 5 4 Designed specifically to meet the requirement for extended operation of battery-powered equipment such as cordless and cellular telephones, the A8405SLH voltage regulators offer the reduced dropout voltage and quiescent current essential for maximum battery life. Applicable also to palmtop computers and personal data assistants, these devices deliver a regulated output at up to 200 mA (transient), which is internally limited, providing short-circuit protection. Regulated output voltages of 2.7, 2.8, 3.0, 3.2, 3.3, 3.6, 3.8, 4.0, and 5.0 V are currently provided. Other voltages, down to 2.0 volts, are available on special order. A PMOS pass element provides a typical dropout voltage of only 100 mV at 100 mA of load current. The low dropout voltage permits deeper battery discharge before output regulation is lost. Quiescent current does not increase significantly as the dropout voltage is approached, an ideal feature in standby/resume power systems where data integrity is crucial. Regulator accuracy and excellent temperature characteristics are provided by a bandgap reference. The A8405SLH includes an ENABLE input to give the designer complete control over power up, standby, or power down. These devices are supplied in a thermally enhanced 5-lead smalloutline plastic package similar to the SOT-23, and fitting the SC-74A footprint. All devices are rated for operation over a temperature range of -20°C to +85°C. T C U Y D L O N R P EO D C E N U E N R I E T F N E O R C S OR I D F — 2 GND 3 ENABLE 1 IN VR Dwg. PS-021-6 *BYPASS (fixed regulators) or ADJUST (A8405SLH-ADJ only). Data Sheet 27468.22 8405 FEATURES AND BENEFITS ABSOLUTE MAXIMUM RATINGS Input Voltage, VI . . . . . . . . . . . . . . . 7 V Peak Output Current, IOM . . . . . . . . . . . . . . . . . . 200 mA* Enable Input Voltage, VE . . . . . . . . . . VI Operating Temperature Range, TA . . . . . . . . . . . . . -20°C to +85°C Junction Temperature, TJ . . . . +150°C Storage Temperature Range, TS . . . . . . . . . . . . -40°C to +150°C * Output current rating is limited by input voltage, duty cycle, and ambient temperature. Under any set of conditions, do not exceed a junction temperature of +150°C. See following pages. ■ ■ ■ ■ ■ ■ High Efficiency Provides Extended Battery Life 100 mV Typical Dropout Voltage at IO = 100 mA 80 µA Typical Quiescent Current Low Output Noise 200 mA Current-Limited Output Improved PSRR and Transient Performance APPLICATIONS ■ ■ ■ ■ ■ ■ Cordless/Cellular/GSM/PHS Telephones Personal Data Assistants Personal Communicators Palmtop Computers GPS Pagers Always order by complete part number, e.g., A8405SLH-xx , where “xx” is the required output voltage in tenths or “ADJ” for adjustable. 8405 LOW-DROPOUT REGULATORS FUNCTIONAL BLOCK DIAGRAM IN 1 5 OUT 5 OUT 4 BYPASS ADJUST 4 DRIVE 3 2 ERROR AMP OVERCURRENT PROTECTION ENABLE ENABLE THERMAL PROTECT. BIAS (SUFFIX "-ADJ" ONLY) (FIXED REG'S) BANDGAP REF. GND Dwg. FS-012-7 A8405SLH Maximum Allowable Average Output Current* with device mounted on 2.24" x 2.24" (56.9 mm x 56.9 mm) solder-coated copper-clad board in still air. Allowable Total Average (10 ms) Output Current in Milliamperes with TJ = 150°C, Duty Cycle = 100%† VI - VO TA 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0* 4.5* 25°C 200 200 200 200 200 189 162 142 126 50°C 200 200 200 200 182 152 130 114 101 70°C 200 200 200 182 145 121 104 91 81 85°C 200 200 197 148 118 98 84 74 66 * Absolute maximum peak output current rating is 200 mA; absolute maximum input voltage is 7 V. † IO = (TJ – TA)/([VI – VO] RθJA x dc) = (150 – TA)/([VI – VO] x 220 x 1.00) Output current rating can be increased (to 200 mA maximum) by additional heat sinking or reducing the duty cycle. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1999, 2000 Allegro MicroSystems, Inc. 8405 LOW-DROPOUT REGULATORS ELECTRICAL CHARACTERISTICS at TA = +25°C, VE ≥ 2.0 V, CBYPASS = TBD (unless otherwise noted). Limits Characteristic Output Voltage (reference specified VO(nom)) Symbol Min. Typ. Max. Units VI ≥ VO(nom) + 1 V, 1 mA ≤ IO ≤ 150 mA* — ±0.5 — % VI ≥ VO(nom) + 1 V, 1 mA ≤ IO ≤ 150 mA*, over operating temperature range — — ±2.0 % VI = VO(nom), IO = 50 mA — — -0.25 V VI = 6 V, IO = 10 mA, TJ ≤ 125°C — TBD — mV/°C 200 — — mA at VI = VO(nom) + 1 V, IO = 3 mA and VI = 7 V, IO = 3 mA — 1.0 2.0 mV at VI = VO(nom) + 1 V, IO = 1 mA and VI = VO(nom) + 1 V , IO = 150 mA* — 2.0 — mV at VI = 7 V, IO = 1 mA and VI = 7 V, IO = 150 mA* — 2.0 — mV IO = 100 mA — 100 — mV VI = VO(nom) + 1 V, IO = 1 mA — 80 100 µA VI = VO(nom) + 1 V, IO = 150 mA* — 80 100 µA VI = 7 V, IO = 1 mA — 80 100 µA VI = 7 V, IO = 150 mA* — 80 100 µA IQ VI ≤ 7 V, VE ≤ 0.8 V, IO = 0 mA — — 1.0 µA VEH VI ≥ VO(nom) + 1 V, Output ON 2.0 — — V VEL VI ≥ VO(nom) + 1 V, Output OFF — — 0.4 V VE = VI = 7 V — — ±1.0 µA — 1.26 — V A8405SLH-ADJ only — 0.10 — µA VI = VO(nom) + 1.5 V, Vi = 100 mV, IO = 30 mA, f = 60 Hz — 70 — dB 10 Hz ≤ f ≤ 100 kHz, IO = 10 mA, CO = 10 µF — 0.2 — µV/√Hz — 170 — °C VO Output Volt. Temp. Coeff. aVO Output Short-Circuit Current IOM Line Regulation Load Regulation Dropout Voltage Ground Terminal Current ENABLE Input Voltage ENABLE Input Current ∆VO(∆VI) ∆VO(∆IO) VImin - VO IGND IE Internal Reference Voltage VREF ADJUST Input Current IADJ Rejection Ratio PSRR Output Noise en Thermal Shutdown TJ Test Conditions Typical values are at TA = +25°C and are given for circuit design information only. * Pulse test (≤20 ms). See previous page for duty cycle limitations. www.allegromicro.com 8405 LOW-DROPOUT REGULATORS APPLICATIONS INFORMATION Linear regulators require input and output capacitors in order to maintain over-all loop stability. The recommended minimum value for the input capacitor is 0.1 µF. The output capacitor is the dominant pole that provides the high-frequency compensation required for over-all regulator loop stability. These devices are stable with as little as 1 µF. However, to ensure stable operation under all conditions and capacitor types, the recommended minimum value is 4.7 µF. The output capacitor may be partially distributed through the load circuits. However, at least 1 µF should be connected at the regulator using the shortest and widest foil pattern possible. The A8405SLH-ADJ requires an external voltage divider to set up the desired regulated output voltage between 2.0 V and 6.8 V (VI ≤ 7 V). The two resistors are chosen such that VO = 1.26 (R1 + R2)/R2. The resistor values are usually as high as possible to maintain high circuit efficiency, but R2 should be less than 300 kΩ. OUTPUT (2.0 V TO 6.8 V) 5 1 INPUT (7.0 V MAX) VR R1 4 3 ENABLE (ACTIVE HIGH) 2 0.1 µF (MIN) 1 µF (MIN) R2 (300 kΩ MAX) Dwg. ES-015 Thermal Considerations These devices are intended to provide more than 150 mA of continuous current in a very small package. The table on page 2 of this data sheet gives the maximum allowable average output current for a worst-case printed circuit design (RθJA = 220°C/W with a minimum footprint). Performance improvement is easily accomplished with the addition of 1 square inch of copper at terminal 2 (RθJA = 170°C/W). 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 8405 LOW-DROPOUT REGULATORS Dimensions in Inches (for reference only) 0.122 0.079 0.018 0.012 0.028 0.083 0.073 5 1 0.0079 0.0059 4 2 3 0.118 0.106 4 5 0.039 0.022 0° TO 8° REF 0.037 0.095 1 0.0098 MIN 2 BSC 3 0.037 0.043 0.035 0.049 0.035 0.0059 0.00 Dwg. MA-010-15 in Dwg. MA-011-5 in Dimensions in Millimeters (controlling dimensions) 3.10 2.90 0.45 0.30 0.70 5 2.10 1.85 5 1 0.20 0.15 4 2 3 3.00 2.70 4 0.55 1.00 0° TO 8° REF 0.95 2.40 1 0.25 MIN 2 BSC 3 0.95 0.15 0.00 1.10 0.90 1.25 0.90 Dwg. MA-011-5 mm NOTES: 1. Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line). 2. Exact body and lead configuration at vendor’s option within limits shown. 3. Height does not include mold gate flash. 4. Where no tolerance is specified, dimension is nominal. www.allegromicro.com Dwg. MA-010-15 mm 8405 LOW-DROPOUT REGULATORS This page intentionally left blank 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 8405 LOW-DROPOUT REGULATORS This page intentionally left blank www.allegromicro.com 8405 LOW-DROPOUT REGULATORS Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of its products. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000