Micro Linear Corporation ML4890ES-T, ML4890CS-5, ML4890CS-T, ML4890ES-3, ML4890ES-5 Datasheet

FEATURING

Extended Commercial Temperature Range

–20°C to 70°C

for Portable Handheld Equipment

April 1997

ML4890

High Efficiency, Low Ripple Boost Regulator

GENERAL DESCRIPTION

The ML4890 is a high efficiency, PFM (Pulse Frequency
Modulation), boost switching regulator connected in
series with an integrated LDO (Low Dropout Regulator)
that incorporates “Silent Switcher™” technology. This
technique incorporates a patented tracking scheme to
minimize the voltage drop across the LDO and increase
the total efficiency of the regulator beyond that which can
be obtained by using a discrete external LDO regulator.

The ML4890 is designed to convert single or multiple cell
battery inputs to regulated output voltages for integrated
circuits and is ideal for portable communications
equipment that cannot tolerate the output voltage ripple
normally associated with switching regulators.

An integrated synchronous rectifier eliminates the need for
an external Schottky diode and provides a lower forward
voltage drop, resulting in higher conversion efficiency.

FEATURES

■ Incorporates “Silent Switcher™” technology to deliver

very low output voltage ripple (typically 5mV)

■ Guaranteed full load start-up and operation at 1.0V

input and low operating quiescent current (<100µA)
for extended battery life

■ Pulse Frequency Modulation and internal synchronous

rectification for high efficiency

■ Minimum external components

■ Low ON resistance internal switching MOSFETs

■ 5V, 3.3V, and 3V output versions

BLOCK DIAGRAM

*C

IN

V

BAT

FROM

POWER

MANAGEMENT

Patent Pending

7

2

SHDN

V

REF

V

IN

1

BOOST

CONTROL

GND

3

L1

5

6

V

L

FEEDBACK

V

BOOST

LDO

CONTROL

V

PWR

GND

OUT

C2

C1

+

V

OUT

–

4

8

*Optional

1

ML4890

PIN CONNECTION

ML4890-5/-3/-T

8-Pin SOIC (S08)

PIN DESCRIPTION

V

GND

V

OUT

V

IN

REF

1

2

3

4

TOP VIEW

8

7

6

5

PWR GND

SHDN

V

L

V

BOOST

PIN

NO. NAME FUNCTION

1V

IN

2V

REF

Battery input voltage

200mV reference output
3 GND Analog signal ground
4V

OUT

LDO linear regulator output

PIN
NO. NAME FUNCTION

5V

BOOST

Boost regulator output for connection
of an output filter capacitor

6V

L

Boost inductor connection

7 SHDN Pulling this pin high shuts down the

regulator, isolating the load from the
input

8 PWR GND Return for the NMOS boost transistor

2

ML4890

ABSOLUTE MAXIMUM RATINGS

Storage Temperature Range .................... –65°C to +150°C

Lead Temperature (Soldering 10s).......................... +260°C

Absolute maximum ratings are those values beyond which
the device could be permanently damaged. Absolute
maximum ratings are stress ratings only and functional
device operation is not implied.

V
Voltage on Any Other Pin ...GND –0.3V to V
Peak Switch Current (I
Average Switch Current (I

........................................................................ 7V

BOOST

) .......................................... 1A

PEAK

) ............................... 500mA

AVG

BOOST

+0.3V

LDO Output Current ............................................. 250mA

Junction Temperature .............................................. 150°C

Thermal Resistance (θ

Plastic SOIC .................................................... 110°C/W

OPERATING CONDITIONS

Temperature Range

ML4890CS-X ............................................ 0°C to +70°C

ML4890ES-X......................................... –20°C to +70°C

V

Operating Range

IN

ML4890CS-X ................................................ 1.0V to 6V

ML4890ES-X................................................. 1.1V to 6V

)

JA

ELECTRICAL CHARACTERISTICS

Unless otherwise specified, V

PARAMETER CONDITIONS MIN TYP. MAX UNITS

Supply

VIN Current VIN = 6V 60 75 µA

V

Quiescent Current V

OUT

VL Quiescent Current 1 µA

= Operating Voltage Range, TA = Operating Temperature Range. (Note 1)

IN

SHDN = high 15 25 µA

BOOST

= V

+ 0.5V 8 10 µA

OUT

Reference

Output Voltage (V

) 0 < I

REF

< –5µA, 195 200 205 mV

PIN2

PFM Regulator

Pulse Width (TON) 4.5 5 5.5 µs

LDO

DC Output Voltage (V

) ML4890-5 V

OUT

ML4890-3 V

ML4890-T V

BOOST

BOOST

BOOST

= V

= V

= V

OUT

OUT

OUT

+ 0.5V, I

+ 0.5V, I

+ 0.5V, I

< 200mA 4.85 5.0 5.15 V

OUT

< 100mA 3.2 3.3 3.4 V

OUT

< 80mA 2.91 3.0 3.09 V

OUT

Load Regulation ML4890-5 See Figure 1

= 1.2V, I

V

IN

VIN = 2.4V, I

ML4890-3 VIN = 1.2V, I

VIN = 2.4V, I

ML4890-T VIN = 1.2V, I

VIN = 2.4V, I

< 7mA 4.85 5.0 5.15 V

OUT

< 50mA 4.85 5.0 5.15 V

OUT

< 14mA 3.2 3.3 3.4 V

OUT

< 75mA 3.2 3.3 3.4 V

OUT

< 15mA 2.91 3.0 3.09 V

OUT

< 60mA 2.91 3.0 3.09 V

OUT

Dropout Voltage ML4890-5 See Figure 1

= 1.2V, I

V

IN

VIN = 2.4V, I

ML4890-3 VIN = 1.2V, I

VIN = 2.4V, I

ML4890-T VIN = 1.2V, I

VIN = 2.4V, I

Output Ripple 5mV

< 7mA 300 mV

OUT

< 50mA 500 mV

OUT

< 14mA 300 mV

OUT

< 75mA 500 mV

OUT

< 15mA 300 mV

OUT

< 60mA 500 mV

OUT

P-P

Shutdown

SHDN Threshold 0.5 0.8 1.0 V

SHDN Bias Current –100 100 nA

Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case conditions.

3

ML4890

V

IN

100µF

33µH

(Sumida CD54)

ML4890

V

PWR GND

IN

1µF

V

REF

GND

V

OUT

SHDN

V

BOOST

100µF

V

L

Figure 1. Application Test Circuit

33µF

I

OUT

V

OUT

OS

+

= f (I

C2

–

LOAD

I

LOAD

4

C1

REF

R1

R2

Q3

+

A3

–

V

)

L1

6

Q2

A2

R

S

5µs

ONE SHOT

Q1

A1

5

+

–

–

+

V

Figure 2. PFM Regulator and LDO Block Diagram

4