Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - DC/DC voltage regulator Holder SOIC 8

_______________General Description

The MAX750A/MAX758A are adjustable-output, CMOS,

step-down, DC-DC switching regulators. The

MAX758A accepts inputs from 4V to 16V and delivers

750mA, while the MAX750A accepts inputs from 4V to

11V and delivers 450mA. Typical efficiencies are 85%

to 90%. Typical quiescent current is 1.7mA, or only

6µA in shutdown mode. The output does not exhibit

any ripple at subharmonics of the switching frequency

over its specified range.

Pulse-width-modulation (PWM) current-mode control

provides precise output regulation and excellent tran-

sient responses. Output voltage accuracy is guaran-

teed to be ±4.5% plus feedback-resistor tolerance over

line, load, and temperature variations. Fixed-frequency

switching and absence of subharmonic ripple allows

easy filtering of output ripple and noise, as well as the

use of small external components. These regulators

require only a single inductor value to work in most

applications, so no inductor design is necessary.

________________________Applications

Cellular Phones & Radios

Portable Communications Equipment

Portable Instruments

Computer Peripherals

____________________________Features

♦ Up to 750mA Load Currents

♦ 160kHz High-Frequency, Current-Mode PWM

♦ 85% to 96% Efficiencies

♦ 33µH or 100µH Pre-Selected Inductor Value,

No Component Design Required

♦ 1.7mA Quiescent Supply Current

♦ 6µA Shutdown Supply Current

♦ Adjustable Output Voltage

♦ Overcurrent, Soft-Start, and Undervoltage

Lockout Protection

♦ Cycle-by-Cycle Current Limiting

♦ 8-Pin DIP/SO Packages (MAX750A)

______________Ordering Information

Ordering Information continued on last page.

* Contact factory for dice specifications.

**Contact factory for availability and processing to MIL-STD-883.

MAX750A/MAX758A

Adjustable, Step-Down,

Current-Mode PWM Regulators

________________________________________________________________

Maxim Integrated Products

V+

GND

I.C.

REF

SHDN

DIP

TOP VIEW

MAX750A

MAX758A

V+

GND

I.C.

REF

MAX750A

SHDN

_________________Pin Configurations

OUTPUT ADJ.

FROM

VREF TO V+

INPUT

4V TO 16V

GND

MAX750A

MAX758A

SHDN

V+

REF

33µH

ON/OFF

__________Typical Operating Circuit

Call toll free 1-800-998-8800 for free samples or literature.

19-0195; Rev 0; 10/93

PART TEMP. RANGE PIN-PACKAGE

MAX750ACPA

0°C to +70°C 8 Plastic DIP

MAX750ACSA 0°C to +70°C 8 SO

MAX750AC/D 0°C to +70°C Dice*

MAX750AMJA -55°C to +125°C 8 CERDIP**

MAX750AESA -40°C to +85°C 8 SO

MAX750AEPA -40°C to +85°C 8 Plastic DIP

Pin Configurations continued on last page.

Summary of content (16 pages)

PAGE 1
9-0195; Rev 0; 10/93 Adjustable, Step-Down, Current-Mode PWM Regulators ________________________Applications Cellular Phones & Radios Portable Communications Equipment Portable Instruments ____________________________Features ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Up to 750mA Load Currents 160kHz High-Frequency, Current-Mode PWM 85% to 96% Efficiencies 33µH or 100µH Pre-Selected Inductor Value, No Component Design Required 1.
PAGE 2
MAX750A/MAX758A Adjustable, Step-Down, Current-Mode PWM Regulators ABSOLUTE MAXIMUM RATINGS Pin Voltages V+ (MAX750A).........................................................+12V, -0.3V V+ (MAX758A).........................................................+18V, -0.3V LX (MAX750A) ....................................(V+ - 12V) to (V+ + 0.3V) LX (MAX758A) ....................................(V+ - 21V) to (V+ + 0.3V) SS, CC, SHDN.............................................-0.3V to (V+ + 0.
PAGE 3
Adjustable, Step-Down, Current-Mode PWM Regulators (Circuit of Figure 3, V+ = 9V for the MAX750A, V+ = 12V for the MAX758A, VOUT = 5V, R2 = 40.20kΩ, R3 = 13.0kΩ, ILOAD = 0mA, TA = TMIN to TMAX, unless otherwise noted.) CONDITIONS PARAMETER MIN MAX750A TYP MAX 4.00 MIN MAX758A TYP MAX 3.75 4.00 UNITS Undervoltage Lockout V+ rising 3.75 V+ falling 3.5 3.5 LX On Resistance ILX = 500mA 0.5 0.5 Ω 1.0 1.0 µA LX Leakage Current Reference Voltage TA = +25°C 1.15 1.22 Reference Drift 1.
PAGE 4
_____________________________Typical Operating Characteristics (continued) (Circuit of Figure 3, VOUT = 5V, TA = +25°C, unless otherwise noted.) MAX758A PEAK INDUCTOR CURRENT vs. OUTPUT CURRENT 600 V+ 8.0V TO 16.0V 400 V+ = 6.6V 200 600 500 400 300 V+ = 10.2V V+ = 8.0V V+ = 6.6V V+ = 6.0V 200 100 220 (NOTE 3) 0 100 200 300 400 500 600 700 800 2.5 UNDERVOLTAGE LOCKOUT V+ FALLING (OPERATION ENDS) 1.0 UNDERVOLTAGE LOCKOUT V+ RISING (OPERATION BEGINS) 2 4 6 8 12 10 150 200 250 14 16 2.
PAGE 5
Adjustable, Step-Down, Current-Mode PWM Regulators MAXIMUM OUTPUT CURRENT vs. SUPPLY VOLTAGE, R1 OMITTED MAXIMUM OUTPUT CURRENT vs.
PAGE 6
MAX750A/MAX758A Adjustable, Step-Down, Current-Mode PWM Regulators _____________________________Typical Operating Characteristics (continued) (Circuit of Figure 3, VOUT = 5V, TA = +25°C, unless otherwise noted.) MAX750A LINE-TRANSIENT RESPONSE MAX758A LINE-TRANSIENT RESPONSE A A 16V 10.2V 11V 6V B 0V B 0V 100ms/div 100ms/div A: VOUT, 50mV/div, AC-COUPLED B: V+, 5V/div, 6.0V TO 11.0V A: VOUT, 50mV/div, AC-COUPLED B: V+, 5V/div, 10.2V TO 16.
PAGE 7
Adjustable, Step-Down, Current-Mode PWM Regulators PIN 8-PIN DIP/SO 16-PIN WIDE SO NAME 1 2 SHDN 2 3 REF Reference Voltage Output (+1.22V) supplies up to 100µA for external loads. Bypass to GND with a capacitor that does not exceed 0.047µF. 3 7 SS Soft-Start. Capacitor between SS and GND provides soft-start and short-circuit protection. 510kΩ resistor from SS to SHDN provides current boost. 4 8 CC External voltage divider feedback point.
PAGE 8
MAX750A/MAX758A Adjustable, Step-Down, Current-Mode PWM Regulators V IN V+ SHDN C2 1µF C3* OVERCURRENT COMPARATOR BIAS GEN SLOPE COMPENSATION Σ MAX750A MAX758A C5 330pF RAMP GEN RSENSE CURRENT SENSE AMP R2 ERROR AMP CC R1 510K R3 F/F R PWM COMPARATOR 1.23V BANDGAP REF C6 0.01µF LX L1 D1 1N5817 OSC VOUT C4* 1M ±35% SS C1 0.1µF Q S UNDERVOLTAGE LOCKOUT SS CLAMP VUVLO GND * SEE TABLE 3 FOR COMPONENT VALUES AND SUPPLIERS. Figure 1.
PAGE 9
Adjustable, Step-Down, Current-Mode PWM Regulators FROM SHDN MAX750A MAX758A R1 510k SS CLAMP SS 1M ±35% C1 1.23V __________Applications Information Figure 3 shows the MAX750A/MAX758A configured for a standard 5V step-down application. Table 2 lists the components for the desired operating temperature range. These circuits are useful in systems that require high current at high efficiency and are powered by an unregulated supply, such as a battery or wall-plug AC-DC transformer.
PAGE 10
MAX750A/MAX758A Adjustable, Step-Down, Current-Mode PWM Regulators Table 1. Typical Soft-Start Times MAX750A CIRCUIT CONDITIONS SOFT-START TIME (ms) vs. C1 (µF) R1 (kΩ) V+ (V) IOUT (mA) C4 (µF) C1 = 0.01 C1 = 0.047 C1 = 0.1 C1 = 0.
PAGE 11
Adjustable, Step-Down, Current-Mode PWM Regulators MAX750A/MAX758A MAX750A: 4.0V TO 11.0V MAX758A: 4.0V TO 16.0V C2 1µF C3* OPTIONAL LOWPASS OUTPUT FILTER 8 1 V+ SHDN LX 7 OUTPUT D1 IN5817 L1* MAX750A MAX758A R1 510k 3 C1 0.1µF I.C. 5 CC GND REF 6 2 FILTER OUTPUT C7 2.2µF OUTPUT 5V C5 330pF SS L2 25µF R2 40.2k C4* 4 R3 13.0k C6 0.01µF PART INPUT SUPPLY RANGE (V) GUARANTEED OUTPUT CURRENT AT 5V OUTPUT (mA) MAX750A 6.0 to 11.0 450 6.0 to 16.0 450 10.2 to 16.
PAGE 12
MAX750A/MAX758A Adjustable, Step-Down, Current-Mode PWM Regulators Table 2. Component Values and Suppliers ASSEMBLY METHOD MAX750AC/MAX758AC COMMERCIAL TEMPERATURE RANGE INDUCTORS L1 = 33µH to 100µH Surface Mount Sumida (708) 956-0666 CD54-101KC (MAX750AC) CD105-101KC (MAX758AC) Coiltronics (305) 781-8900 CTX100 series CAPACITORS C3 = 68µF, 16V C4 = 100µF, 6.
PAGE 13
Adjustable, Step-Down, Current-Mode PWM Regulators Figure 5. DIP PC Layout, Component Side (1x Scale) Figure 6. DIP PC Layout, Solder Side (1x Scale) Figure 7. DIP PC Layout, Drill Guide (1x Scale) ______________________________________________________________________________________ MAX750A/MAX758A Figure 4.
PAGE 14
MAX750A/MAX758A Adjustable, Step-Down, Current-Mode PWM Regulators ____Pin Configurations (continued) __Ordering Information (continued) TOP VIEW V+ 1 16 V+ SHDN 2 15 V+ REF 3 N.C. 4 14 LX MAX758A 13 LX N.C. 5 12 LX N.C. 6 11 GND SS 7 10 GND CC 8 9 PART TEMP.
PAGE 15
Adjustable, Step-Down, Current-Mode PWM Regulators DIM D1 A A1 A2 A3 B B1 C D D1 E E1 e eA eB L α E E1 D A3 A A2 L A1 INCHES MAX MIN 0.200 – – 0.015 0.175 0.125 0.080 0.055 0.022 0.016 0.065 0.050 0.012 0.008 0.390 0.348 0.035 0.005 0.325 0.300 0.280 0.240 0.100 BSC 0.300 BSC 0.400 – 0.150 0.115 15˚ 0˚ MILLIMETERS MIN MAX – 5.08 0.38 – 3.18 4.45 1.40 2.03 0.41 0.56 1.27 1.65 0.20 0.30 8.84 9.91 0.13 0.89 7.62 8.26 6.10 7.11 2.54 BSC 7.62 BSC – 10.16 2.92 3.
PAGE 16
MAX750A/MAX758A Adjustable, Step-Down, Current-Mode PWM Regulators ___________________________________________Package Information (continued) DIM E A A1 B C D E e H h L α H INCHES MAX MIN 0.104 0.093 0.012 0.004 0.019 0.014 0.013 0.009 0.413 0.398 0.299 0.291 0.050 BSC 0.419 0.394 0.030 0.010 0.050 0.016 8˚ 0˚ MILLIMETERS MIN MAX 2.35 2.65 0.10 0.30 0.35 0.49 0.23 0.32 10.10 10.50 7.40 7.60 1.27 BSC 10.00 10.65 0.25 0.75 0.40 1.27 0˚ 8˚ 21-589B h x 45˚ D α A 0.127mm 0.004in.