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_______________General Description

The MAX1822 high-side supply, using a regulated

charge pump, generates a regulated output voltage

11V greater than the input supply voltage to power

high-side switching and control circuits. The MAX1822

allows low-resistance N-channel MOSFETs (FETs) to be

used in circuits that normally require costly, less effi-

cient P-channel FETs and PNP transistors. The high-

side output also eliminates the need for logic FETs in

+5V and other low-voltage switching circuits.

A +3.5V to +16.5V input supply range and a typical qui-

escent current of only 150µA make the MAX1822 ideal

for a wide range of line- and battery-powered switching

and control applications where efficiency is crucial.

Also provided is a logic-level power-ready output (PR)

to indicate when the high-side voltage reaches the

proper level.

The MAX1822 comes in an 8-pin SO package and

requires three inexpensive external capacitors. The

MAX1822 is a pin-for-pin replacement to the MAX622.

________________________Applications

High-Side Power Control with N-Channel FETs

Low-Dropout Voltage Regulators

Power Switching from Low Supply Voltages

H-Switches

Stepper Motor Drivers

Battery-Load Management

Portable Computers

____________________________Features

♦ +3.5V to +16.5V Operating Supply Voltage Range

♦ Output Voltage Regulated to V

+ 11V (typ)

♦ 150µA (typ) Quiescent Current

♦ Power-Ready Output

MAX1822

High-Side Power Supply

________________________________________________________________ Maxim Integrated Products 1

C2+

OUT

GND

C1-C2-

C1+

TOP VIEW

MAX1822

Pin Configuration

MAX1822

+3.5V TO +16.5V

0.1µF

CERAMIC

GND

+12.5V TO +27.5V

OUT

C1+

C1-

C2+

C2-

Typical Operating Circuit

19-1892; Rev 0; 1/01

PART

MAX1822ESA -40°C to +85°C

TEMP. RANGE PIN-PACKAGE

8 SO

Ordering Information

For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

Summary of content (10 pages)

PAGE 1
9-1892; Rev 0; 1/01 High-Side Power Supply ____________________________Features ♦ +3.5V to +16.5V Operating Supply Voltage Range A +3.5V to +16.5V input supply range and a typical quiescent current of only 150µA make the MAX1822 ideal for a wide range of line- and battery-powered switching and control applications where efficiency is crucial. Also provided is a logic-level power-ready output (PR) to indicate when the high-side voltage reaches the proper level.
PAGE 2
MAX1822 High-Side Power Supply ABSOLUTE MAXIMUM RATINGS VCC ......................................................................................+17V VOUT ....................................................................................+30V IOUT ...................……………………………………………….25mA Continuous Total Power Dissipation (TA = +70°C) 8-pin SO (derate 5.88mW/°C above +70°C)...............471mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............
PAGE 3
High-Side Power Supply C* = 0.01µF C* = 0.047µF C* = 0.022µF 250 200 150 VCC = +5V, IOUT = 0 TA = +25°C C1 = C2 = C* 100 C* = 0.1µF 50 1 2 3 4 5 6 7 9 200 150 100 50 1 10 2 3 4 5 6 7 8 9 C3 CAPACITOR VALUE (µF) MAX1822 SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX1822 MAXIMUM OUTPUT CURRENT vs. C1 = C2 CAPACITOR VALUE IOUT = 0 C3 = 1µF TA = +25°C 1.2 1000 0.8 0.6 C1 = C2 = 0.01µF 0.
PAGE 4
High-Side Power Supply MAX1822 OUTPUT VOLTAGE RIPPLE vs. RESERVOIR CAPACITOR C3 TA = +25°C 180 VCC = +16.5V IOUT = 1mA C1 = C2 = 0.01µF 140 120 TURN-ON TIME (ms) VOUT RIPPLE (mV) 160 10 MAX1822 toc07 200 MAX1822 TURN-ON TIME vs. SUPPLY VOLTAGE 100 VCC = +5V IOUT = 500µA C1 = C2 = 0.047µF 80 60 IOUT = 0 TA = +25°C MAX1822 toc08 MAX1822 Typical Operating Characteristics (continued) 1 40 20 0 0.
PAGE 5
High-Side Power Supply MAX1822 VOUT S8 11V POWER-READY COMPARATOR S7 C3 8.5V VINT RC OSCILLATOR + CONTROL LOGIC C2 S6 OVERVOLTAGE COMPARATOR S4 S3 VCC C1 S2 PR PR DRIVER S1 S5 GND TWO-STAGE CHARGE PUMP (SWITCHES SHOWN IN REFRESH MODE) Figure 1. MAX1822 Block Diagram Detailed Description Charge-Pump Operation The MAX1822 is a multistage charge-pump power supply.
PAGE 6
High-Side Power Supply MAX1822 Output Ripple C3 1.0µF VSUPPLY VOUT ripple is typically 50mVp-p with VCC = +5V, C1 and C2 = 0.047µF, and C3 = 1µF (Typical Operating Characteristics). Ripple can be reduced by increasing the ratio between the output storage capacitors C3 and C1 and C2. This is usually accomplished by increasing C3 and keeping C1 and C2 in the 0.01µF to 0.047µF range. For example, if C1 and C2 are 0.
PAGE 7
High-Side Power Supply MAX1822 H-BRIDGE MOTOR CONTROL +5V 14 V+ 8 1 C3 10µF VCC C1 C1 0.047µF VOUT 7 5 4 11 D1 S2 D2 S4 13 C2+ 9 C2- + DG303 6 C2 0.047µF 2 DC MOTOR +5V C1MAX1822 6 IRF541 IRF541 10 GND 4 IN1 S3 IN2 S1 GND 7 D3 3 – 5 IRF541 IRF541 D4 12 REVERSE FORWARD Figure 4. H-Bridge Motor Controller internal switches during charge-pump cycles. This may damage the device.
PAGE 8
MAX1822 High-Side Power Supply 4-CHANNEL LOAD SWITCH—NO PULLUP RESISTORS +3.5V TO +16.5V ALL TRANSISTORS = IRF541 (NOTE 1) TO LOAD C3 10µF C4 1µF 1 VCC C1+ VOUT 5 16 V+ TO LOAD 2 C1 0.01µF N01 7 9 12 C2+ 19 4 2 C2- 8 COM2 N02 C1MAX1822 6 C2 0.01µF 3 COM1 8 GND 4 7 14 17 MAX333 N03 TO LOAD N04 13 COM3 NC1 TO LOAD NC2 NC3 18 COM4 NC4 ALL CAPACITORS = 1µF (NOTE 2) 5 VIN1 NOTE 1: TRANSISTOR TYPE DEPENDS ON LOAD-CURRENT REQUIREMENTS.
PAGE 9
High-Side Power Supply MAX1822 Fig 06 DROPOUT VOLTAGE vs. LOAD CURRENT 225 TA = +25°C 200 8 1 C1+ VCC C3 10µF VOUT C1 0.01µF 7 6 C1- MAX1822 PR VBATT 5 D1 R3 1k 3 1N914 R2 24k 3 C2+ 2 C2 0.01µF DROPOUT VOLTAGE (mV) C5 0.1µF 7 1 LM10 R1 8 6 1k Q1 IRF541 C2- GND 4 175 150 125 IRF541 100 75 SMP60N06 25 C6 1000µF IRFZ40 50 4 2 MAX1822 C4 0.1µF +5V 0 0.1 1 10 LOAD CURRENT (A) ENABLE/SHUTDOWN D2 1N914 Figure 6.
PAGE 10
________________________________________________________Package Information SOICN.EPS MAX1822 High-Side Power Supply Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.