Diodes ZLDO500 User Manual

5.0 VOLT ULTRA LOW DROPOUT REGULATOR

ISSUE 2 - JULY 1997

ZLDO500

DEVICE DESCRIPTION

The ZLDO Series low dropout linear regulators operate with an exceptionally low dropout voltage, typically only 30mV with a load current of 100mA. The regulator series features output voltages in the range

2.7 to 18 volts, this device provides an output voltage of 5.0 volts.

The ZLDO500 consumes a typical quiescent current of only 1mA at its maximum rated output current of 300mA. A battery low flag is available to indicate potential power fail situations. If the input voltage falls to within 200mV of the regulated output voltage then the error output pulls low. The device also features an active high disable control. Once disabled the ZLDO quiescent current falls to typically 11µA.

The ZLDO devices are packaged in Zetex SM8 8 pin small outline surface mount package, ideal for applications where space saving is important. The device low dropout voltage, low quiescent current and small size make it ideal for low power and battery powered applications. Battery powered circuits can make particular use of the low battery flag and shutdown features.

Low Battery Flag

THERMAL SHUTDOWN

FEATURES

•

APPLICATIONS

•

LOW BATTERY COMPARATOR

Very low dropout voltage 6mV dropout at 10mA output 30mV dropout at 100mA output 100mV dropout at 300mA output

5.0 volt fixed output Other voltages available Low quiescent current 1mA quiescent at 300mA output Low battery flag Shutdown control Surface mount package

Battery powered devices Portable instruments Portable communications Laptop/Palmtop computers Electronic organisers

Vin

Shutdown Control

SHUTDOWN

BIAS

CIRCUIT

4-80

Gnd

OUTPUT DRIVE

BANDGAP REFERENCE

Shaping

ZLDO500

ABSOLUTE MAXIMUM RATING

Input Supply Voltage Range -0.3 to 20V Shutdown Input Voltage Range -0.3 to Vin Low Battery Output

Voltage Range -0.3 to 20V

ELECTRICAL CHARACTERISTICS TEST CONDITIONS (Unless otherwise stated) T

Parameter SYMBOL CONDITIONS MIN TYP MAX UNITS Output voltage V Output voltage

temperature coefficient

Line regulation

Load regulation

Dropout voltage (Note3)

Quiescent current I Quiescent current

at shutdown Shutdown control input

current Shutdown control

threshold voltage

Output current in shutdown mode (Note4)

Output noise voltage (Note4)

Low battery detect voltage

Low battery flag output voltage

Low battery flag leakage current

∆T

∆V ∆V

in-Vo

ins

in(bld)

Vin=6.0V 4.9 5.0 5.1 V Vin=6.0V

(Note 2, Note 4)

Vin=6.0 to 20V 20 70 mV

IL=10 to 300mA V

=6V

IL=10mA I

=100mA

=300mA

Vin=6.0V, IL=0 0.63 1 mA Vin=6.0V, IL=0,

shdn=Vin

Vin=6.0V low(on) high(off) 1.5

Vin=20V

=Gnd

Vin=6.0V f=10Hz to100kHz, I

=100mA

Ibl=100µA, V

in<Vo

Vbl=6V, V

in>Vo

Output Current 300mA Operating Temperature -40 to 85°C Storage Temperature -55 to 150°C Power Dissipation

(Tamb=25°C) 2W (Note 1)

=25°C,IL=10mA,Cs=10pF,C

amb

100 250 ppm/°C

70 123 mV

6 30 100

10 75 200

11 30

=6.0V 2 10

0.4 V

50 100 nA

190

VO +

0.2V

VO +

0.4V

0.16 0.4 V

+200mV

0.1 1

+400mV

µA

µV RMS

µA

out

=1µF

4-81

ZLDO500

NOTES.

1. Maximum power dissipation of the device is calculated assuming the package is mounted on a

PCB measuring 2 inches square.

change x

2 Output voltage temperature coefficient is calculated as:-

3. Dropout voltage is defined as the input to output voltage differential at which the circuit ceases

to regulate. The value is measured when the output voltage has dropped by 100mV from V measured at the nominal input Vin = V

4. Guaranteed by design.

FUNCTIONAL DESCRIPTION

The ZLDO is a high performance, ultra low dropout, low quiescent regula tor. Available in SM8 surface mount packaging, the device is able to dissipate 2W(note 1) allowing complete design flexibility with an input span upto 20V and 300mA output current. The device quiescent is 1mA (typ) at 300mA load current. A low battery comparator signifies

PIN DEFINITIONS Pin 1 LBF - Low Battery Flag. An open

collector NPN output which pulls low on failing input supply.

Pin 2 SC - Shutdown Control. This high impedance logic compatible input disables the regulator when taken high. It includes a diode wired to Vin and so will pass current if taken more than 0.5V above Vin.

Pin 3 Vin - Voltage Input. The power supply to the regulator. The permissible input voltage range is -0.3 to 20V. An input capacitor is not mandatory but will be useful in reducing the coupling of noise from input to output and minimising the effect of sudden changes in load current on the input voltage.

Pin 4 N/C - Not Connected. Not internally connected and so can be left open or wired to any pin without af fecting the performance of the regulator.

out

+ 1V

temperature change

impending battery failure, whilst a shutdown function reduces quiescent current to a mere 11µA (typ). A precision bandgap reference gives ± 2.5% output tolerance and good temperature characteristics over the range

-40 to +85°C. AC performance is enhanced via the use of a small external capacitor.

Pin 5 Vout - Voltage Output. The output of the regulator. An output capacitor of 1uF or greater and having low ESR should be wired in close proximity to the regulator to ensure stability for all loads.

Pin 6 D/C - Do Not Connect. This pin is wired to an internal circuit node of the regulator. No external connection should be made to this pin.

Pin 7 Gnd - Ground. The ground connection of the regulator against which the output voltage is referenced.

Pin 8 Spg - Shaping. The shaping node for the error amplifier of the regulator. A capacitor of 10pF wired from this pin to the output pin (pin 5) gives optimum stability. Improved AC can be achieved by reducing the value of this capacitor but stability may be impaired for some load conditions.

1000000

out

4-82

+ 6 hidden pages