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General Description

The MAX5070/MAX5071 BiCMOS, high-performance,

current-mode PWM controllers have all the features

required for wide input voltage range isolated/nonisolated

power supplies. These controllers are used for low- and

high-power universal input voltage and telecom power

supplies.

The MAX5070/MAX5071 contain a fast comparator with

only 60ns typical delay from current sense to the output

for overcurrent protection. The MAX5070A/MAX5070B

have an integrated error amplifier with the output at

COMP. Soft-start is achieved by controlling the COMP

voltage rise using external components.

The frequency is adjustable from 20kHz to 1MHz with

an external resistor and capacitor. The timing capacitor

discharge current is trimmed allowing for programma-

ble dead time and maximum duty cycle for a given fre-

quency. The available saw-toothed waveform at R

can be used for slope compensation when needed.

The MAX5071A/MAX5071B include a bidirectional syn-

chronization circuit allowing for multiple controllers to

run at the same frequency to avoid beat frequencies.

Synchronization is accomplished by simply connecting

the SYNC pins of all devices together. When synchro-

nizing with other devices, the MAX5071A/MAX5071B

with the highest frequency synchronizes the other

devices. Alternatively, the MAX5071A/MAX5071B can

be synchronized to an external clock with an open-

drain output stage running at a higher frequency.

The MAX5071C provides a clock output pulse

(ADV_CLK) that leads the driver output (OUT) by

110ns. The advanced clock signal is used to drive the

secondary-side synchronous rectifiers.

The MAX5070/MAX5071 are available in 8-pin µMAX

and SO packages and operate over the automotive tem-

perature range of -40°C to +125°C.

Applications

Universal Input AC/DC Power Supplies

Isolated Telecom Power Supplies

Isolated Power-Supply Modules

Networking Systems

Computer Systems/Servers

Industrial Power Conversion

Isolated Keep-Alive Circuits

Features

♦ Pin-for-Pin Replacement for UC2842 (MAX5070A)

and UC2844 (MAX5070B)

♦ 2A Drive Source and 1A Sink Capability

♦ Up to 1MHz Switching Frequency Operation

♦ Bidirectional Synchronization

(MAX5071A/MAX5071B)

♦ Advanced Output Drive for Secondary-Side

Synchronous Rectification (MAX5071C)

♦ Fast 60ns Cycle-by-Cycle Current Limit

♦ Trimmed Oscillator Capacitor Discharge Current

Sets Maximum Duty Cycle Accurately

♦ Accurate 5% Start and Stop Voltage with 6V

Hysteresis

♦ Low 32µA Startup Current

♦ 5V Regulator Output (VREF) with 20mA Capability

♦ Overtemperature Shutdown

MAX5070/MAX5071

High-Performance, Single-Ended, Current-Mode

PWM Controllers

________________________________________________________________ Maxim Integrated Products 1

OUT

GNDR

VREF

COMP

µMAX/SO

TOP VIEW

MAX5070A

MAX5070B

Pin Configurations

Ordering Information

19-3283; Rev 3; 10/06

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Ordering Information continued at end of data sheet.

Selector Guide appears at end of data sheet.

Specify lead-free by adding the + symbol at the end of the part

number when ordering.

PART TEMP RANGE

PIN-PACKAGE

MAX5070AASA

-40°C to +125°C

8 SO

MAX5070AAUA

-40°C to +125°C

8 µMAX

MAX5070BASA

-40°C to +125°C

8 SO

MAX5070BAUA

-40°C to +125°C

8 µMAX

Pin Configurations continued at end of data sheet.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Summary of content (22 pages)

PAGE 1
9-3283; Rev 3; 10/06 High-Performance, Single-Ended, Current-Mode PWM Controllers The MAX5070/MAX5071 BiCMOS, high-performance, current-mode PWM controllers have all the features required for wide input voltage range isolated/nonisolated power supplies. These controllers are used for low- and high-power universal input voltage and telecom power supplies. The MAX5070/MAX5071 contain a fast comparator with only 60ns typical delay from current sense to the output for overcurrent protection.
PAGE 2
MAX5070/MAX5071 High-Performance, Single-Ended, Current-Mode PWM Controllers ABSOLUTE MAXIMUM RATINGS VCC (Low-Impedance Source) to GND ..................-0.3V to +30V VCC (ICC < 30mA).....................................................Self Limiting OUT to GND ...............................................-0.3V to (VCC + 0.3V) OUT Current.............................................................±1A for 10µs FB, SYNC, COMP, CS, RT/CT, VREF to GND ...........-0.3V to +6V COMP Sink Current (MAX5070).....
PAGE 3
High-Performance, Single-Ended, Current-Mode PWM Controllers (VCC = +15V, RT = 10kΩ, CT = 3.3nF, VVREF = OPEN, CVREF = 0.1µF, COMP = OPEN, VFB = 2V, CS = GND, TA = -40°C to +85°C, unless otherwise noted.) (Note 1) PARAMETER Power-Supply Rejection Ratio SYMBOL MIN TYP MAX UNITS 12V ≤ VCC ≤ 25V 70 VCOMP = 0V -1 tCS_DELAY 50mV overdrive 60 OUT Low-Side On-Resistance VRDS_ONL ISINK = 200mA 4.5 10 Ω OUT High-Side On-Resistance VRDS_ONH ISOURCE = 100mA 3.
PAGE 4
MAX5070/MAX5071 High-Performance, Single-Ended, Current-Mode PWM Controllers ELECTRICAL CHARACTERISTICS (continued) (VCC = +15V, RT = 10kΩ, CT = 3.3nF, VVREF = OPEN, CVREF = 0.1µF, COMP = OPEN, VFB = 2V, CS = GND, TA = -40°C to +85°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP 2.4 3 MAX UNITS ADV_CLK (MAX5071C only) ADV_CLK High Voltage VADV_CLKH IADV_CLK = 10mA source ADV_CLK Low Voltage VADV_CLKL IADV_CLK = 10mA sink V 0.
PAGE 5
High-Performance, Single-Ended, Current-Mode PWM Controllers (VCC = +15V, RT = 10kΩ, CT = 3.3nF, VVREF = OPEN, CVREF = 0.1µF, COMP = OPEN, VFB = 2V, CS = GND, TA = -40°C to +125°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS (Notes 3, 4) 2.85 3 3.26 V/V MAX5070A/B (Note 3) 0.95 1 1.05 VCOMP = 5V, MAX5071_ 0.95 1 1.
PAGE 6
ELECTRICAL CHARACTERISTICS (continued) (VCC = +15V, RT = 10kΩ, CT = 3.3nF, VVREF = OPEN, CVREF = 0.1µF, COMP = OPEN, VFB = 2V, CS = GND, TA = -40°C to +125°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL SYNC Leakage Current CONDITIONS ISYNC MIN VSYNC = 0V TYP MAX UNITS 0.01 0.1 µA ADV_CLK (MAX5071C only) ADV_CLK High Voltage VADV_CLKH IADV_CLK = 10mA source ADV_CLK Low Voltage VADV_CLKL IADV_CLK = 10mA sink 2.4 3 V 0.
PAGE 7
High-Performance, Single-Ended, Current-Mode PWM Controllers 5.3 5.20 5.15 5.0 4.90 4.7 4.85 4.6 4.80 4.5 4.995 4.75 4.990 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 30 10 45 12 14 16 18 20 22 IREF (mA) VCC (V) OSCILLATOR FREQUENCY (fOSC) vs. TEMPERATURE OSCILLATOR RT/CT DISCHARGE CURRENT vs. TEMPERATURE MAXIMUM DUTY CYCLE vs. TEMPERATURE 510 500 490 480 470 460 450 8.35 8.30 8.25 8.20 8.15 MAX5070A/MAX5071A 80 8.45 8.40 RT = 3.
PAGE 8
Typical Operating Characteristics (continued) (VCC = 15V, TA = +25°C, unless otherwise noted.) OUT IMPEDANCE vs. TEMPERATURE (RDS_ON PMOS DRIVER) 10 1 CT = 10nF CT = 4.7nF CT = 3.3nF CT = 2.2nF 0.1 ISOURCE = 100mA 9.0 8.5 ISINK = 200mA 8.0 7.5 RDS_ON (Ω) 100 5.0 4.8 4.6 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 MAX5070 toc13 MAX5070 toc12 CT = 1nF CT = 560pF CT = 220pF CT = 100pF RDS_ON (Ω) 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.
PAGE 9
High-Performance, Single-Ended, Current-Mode PWM Controllers IOUT 2A/div SUPPLY CURRENT (mA) 90 80 8 TA = +125°C 7 6 MAX5070 toc22 9 VOUT 10V/div 100 MAX5070 toc21 10 TA = +85°C TA = +25°C 5 DUTY CYCLE (%) MAX5070 toc20 VCC = 15V COUT = 10nF MAX5070A/MAX5071A MAXIMUM DUTY CYCLE vs. RT SUPPLY CURRENT (ICC) vs.
PAGE 10
MAX5070/MAX5071 High-Performance, Single-Ended, Current-Mode PWM Controllers Pin Descriptions (continued) MAX5071A/MAX5071B/MAX5071C PIN NAME FUNCTION 1 COMP COMP is level-shifted and connected to the inverting input of the PWM comparator. Pull up COMP to VREF through a resistor and connect an optocoupler from COMP to GND for proper operation. 2 — SYNC Bidirectional Synchronization Input. When synchronizing with other MAX5071A/MAX5071Bs, the higher frequency part synchronizes all other devices.
PAGE 11
High-Performance, Single-Ended, Current-Mode PWM Controllers UVLO 2.5V REFERENCE 2.5V 16V/10V PREREGULATOR 5V VOLTAGEDIVIDER 2.5V 7 VCC THERMAL SHUTDOWN EN-REF 26.5V VDD BG 5V REGULATOR SNS EN-DRV-BAR REG_OK 8 VREF VP DELAY VOLTAGEDIVIDER 1V ILIM S 6 OUT Q CLK R CS 3 CPWM GND 5 OSC Q 4 RT/CT 2R VEA FB 2 COMP 1 R 100% MAX DUTY CYCLE (MAX5070A) 50% MAX DUTY CYCLE (MAX5070B) Figure 1.
PAGE 12
MAX5070/MAX5071 High-Performance, Single-Ended, Current-Mode PWM Controllers VP MAX5071A/MAX5071B UVLO 2.5V 1V REFERENCE 2.5V 16V/10V PREREGULATOR 5V VOLTAGEDIVIDER 2.5V 7 VCC THERMAL SHUTDOWN EN-REF 26.5V VDD BG 5V REGULATOR SNS EN-DRV-BAR REG_OK 8 VREF VP DELAY VOLTAGEDIVIDER 1V ILIM S Q 6 OUT CLK R CS 3 CPWM GND 5 OSC Q 100% MAX DUTY CYCLE (MAX5071A) 50% MAX DUTY CYCLE (MAX5071B) 2R COMP 1 4 RT/CT R SYNC 2 BIDIRECTIONAL SYNC Figure 2.
PAGE 13
High-Performance, Single-Ended, Current-Mode PWM Controllers MAX5070/MAX5071 VP MAX5071C UVLO 2.5V 1V REFERENCE 2.5V 16V/10V PREREGULATOR 5V 2.5V 7 VCC THERMAL SHUTDOWN EN-REF 26.5V VDD BG 5V REGULATOR SNS EN-DRV-BAR REG_OK VOLTAGEDIVIDER 8 VREF VP DELAY VOLTAGEDIVIDER 1V ILIM S Q 6 OUT CLK R CS 3 CPWM GND 5 OSC Q 50% MAX DUTY CYCLE 2R 4 RT/CT COMP 1 R ADV_CLK 2 Figure 3.
PAGE 14
MAX5070/MAX5071 High-Performance, Single-Ended, Current-Mode PWM Controllers To calculate the capacitance required, use the following formula: ⎡ ⎛V − 13V ⎞ ⎤ ⎢ICC + IG − ⎜ INMIN ⎟ ⎥(t SS ) RST ⎝ ⎠ ⎥⎦ ⎢⎣ CST = VHYST where: IG = QG fSW ICC is the MAX5070/MAX5071s’ maximum internal supply current after startup (see the Typical Operating Characteristics to find the IIN at a given fOSC).
PAGE 15
High-Performance, Single-Ended, Current-Mode PWM Controllers The MAX5071A/MAX5071B/MAX5071C are designed to be used with either an external error amplifier when designed into a nonisolated converter or an error amplifier and optocoupler when designed into an isolated power supply. The COMP input is level-shifted and connected to the inverting terminal of the PWM comparator (CPWM). Connect the COMP pin to the output of the external error amplifier for nonisolated design.
PAGE 16
MAX5070/MAX5071 High-Performance, Single-Ended, Current-Mode PWM Controllers Advance Clock Output (ADV_CLK) (MAX5071C) ADV_CLK is an advanced pulse output provided to facilitate the easy implementation of secondary-side synchronous rectification using the MAX5071C. The ADV_CLK pulse width is 85ns (typically) with its rising edge leading the rising edge of OUT by 110ns.
PAGE 17
High-Performance, Single-Ended, Current-Mode PWM Controllers VIN RST VOUT CST 1 R1 2 R2 3 RT 4 COMP VREF FB MAX5070A VCC MAX5070B CS OUT RT/CT GND 8 7 6 N 5 CT RCS Figure 6. MAX5070A/MAX5070B Typical Application Circuit (Non-Isolated Flyback) VIN RST SYNC INPUT/OUTPUT VOUT CST RSYNC 1 2 RT 3 4 COMP VREF SYNC MAX5071A VCC MAX5071B CS OUT RT/CT GND 8 7 6 N 5 CT RCS Figure 7.
PAGE 18
High-Performance, Single-Ended, Current-Mode PWM Controllers MAX5070/MAX5071 Typical Application Circuits (continued) VD VIN VOUT RST N QS CST N QR VD VCC VREF RT N OUT MAX5071C RT/CT CS CT RCS COMP ADV_CLK MAX5078 GND 0.5V/µs PULSE TRANSFORMER Figure 8.
PAGE 19
High-Performance, Single-Ended, Current-Mode PWM Controllers VIN VIN VCC VREF RT VCC OUT VREF RT MAX5071A MAX5071B RT/CT N VCC OUT N N MAX5071A MAX5071B CS CT SYNC GND OUT RT/CT CS CT SYNC VREF RT MAX5071A MAX5071B RT/CT CS CT MAX5070/MAX5071 VIN SYNC GND GND TO OTHER MAX5071A/Bs RSYNC Figure 9.
PAGE 20
MAX5070/MAX5071 High-Performance, Single-Ended, Current-Mode PWM Controllers Selector Guide PART FEEDBACK/ ADVANCED CLOCK MAXIMUM DUTY CYCLE (%) PIN-PACKAGE PIN COMPATIBLE MAX5070AASA Feedback 100 8 SO UC2842/UCC2842 MAX5070AAUA Feedback 100 8 µMAX UC2842/UCC2842 MAX5070BASA Feedback 50 8 SO UC2844/UCC2844 MAX5070BAUA Feedback 50 8 µMAX UC2844/UCC2844 MAX5071AASA Sync. 100 8 SO — MAX5071AAUA Sync. 100 8 µMAX — MAX5071BASA Sync. 50 8 SO — MAX5071BAUA Sync.
PAGE 21
High-Performance, Single-Ended, Current-Mode PWM Controllers N E H INCHES MILLIMETERS MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050 MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 SOICN .EPS DIM A A1 B C e E H L 1.27 VARIATIONS: 1 INCHES TOP VIEW DIM D D D MIN 0.189 0.337 0.386 MAX 0.197 0.344 0.394 MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.
PAGE 22
Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 4X S 8 E Ø0.50±0.1 8 INCHES DIM A A1 A2 b H c D e E H 0.6±0.1 1 L 1 α 0.6±0.1 S BOTTOM VIEW D MIN 0.002 0.030 MAX 0.043 0.006 0.037 0.014 0.010 0.007 0.005 0.120 0.116 0.0256 BSC 0.120 0.116 0.198 0.188 0.026 0.016 6° 0° 0.0207 BSC 8LUMAXD.