Datasheet

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General Description

The MAX5077 is a +4.5V to +15V push-pull, current-fed

topology driver subsystem with an integrated oscillator

used in telecom module power supplies. The device

drives two MOSFETs connected to a center-tapped

transformer primary providing secondary-side, isolated,

negative or positive voltages. The MAX5077 features a

programmable accurate integrated oscillator with a

synchronizing clock output to synchronize an external

PWM regulator. A single external resistor programs the

internal oscillator frequency from 50kHz to 1.5MHz.

The MAX5077 incorporates dual MOSFET drivers with

±3A peak drive currents and 50% duty cycle. The

MOSFET drivers generate complementary signals to

drive external ground-referenced n-channel MOSFETs.

The MAX5077 clock output frequency is programmable

by logic inputs to set the clock output to 1x, 2x, or 4x

the MOSFET’s driver frequency.

The MAX5077 is available in a 14-pin exposed pad

TSSOP package and is specified over the -40°C to

+125°C operating temperature range.

Applications

Current-Fed Power Supplies

Power-Supply Building Subsystems

Push-Pull Driver Subsystems

Features

♦ Dedicated Current-Fed, Push-Pull Driver

Subsystem

♦ Oscillator Frequency Programmable from 50kHz

to 1.5MHz

♦ Single +4.5V to +15V Supply Voltage Range

♦ ±3A Peak Gate-Drive Current

♦ 1mA Operating Current at 250kHz with No

Capacitive Load

♦ Selectable Synchronizing Clock Frequency for a

Preceding PWM Stage

♦ Thermally Enhanced 14-Pin TSSOP

♦ -40°C to +125°C Operating Temperature Range

MAX5077

Push-Pull FET Driver with Integrated Oscillator

and Programmable Clock Output

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-3663; Rev 1; 6/07

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.

Pin Configuration appears at end of data sheet.

PART

TEMP RANGE

PIN-PACKAGE

PKG

CODE

MAX5077AUD

-40°C to +125°C 14 TSSOP-EP*

U14E-3

*EP = Exposed paddle.

Typical Operating Circuit

MAX5077

DGND

AGND

NDRV2

DRVH

DRVL

1nF

GND

PWM

CONTROLLER

NDRV1

SEL2

SEL1

PGND

SYNCIN

CLK

OUT

GND

I.C.

4.7kΩ

Summary of content (9 pages)

PAGE 1
9-3663; Rev 1; 6/07 Push-Pull FET Driver with Integrated Oscillator and Programmable Clock Output Features The MAX5077 is a +4.5V to +15V push-pull, current-fed topology driver subsystem with an integrated oscillator used in telecom module power supplies. The device drives two MOSFETs connected to a center-tapped transformer primary providing secondary-side, isolated, negative or positive voltages.
PAGE 2
MAX5077 Push-Pull FET Driver with Integrated Oscillator and Programmable Clock Output ABSOLUTE MAXIMUM RATINGS VCC to AGND, DGND, PGND.................................-0.3V to +18V PGND, DGND to AGND ........................................-0.3V to +0.3V SEL1, SEL2 to DGND .............................................-0.3V to +18V CLK, RT to AGND.....................................................-0.3V to +6V NDRV1, NDRV2 to PGND...........................-0.3V to (VCC + 0.3V) CLK Current.................
PAGE 3
Push-Pull FET Driver with Integrated Oscillator and Programmable Clock Output (VCC = +12V, SEL1 = VCC, SEL2 = DGND, RRT = 124kΩ, NDRV1 = NDRV2 = open, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP 3 2.5 MAX UNITS 1 µA SEL_ INPUTS Input Current 0V ≤ VSEL_ ≤ VCC Input High Voltage VIH Input Low Voltage VIL V 2 1.5 V Note 1: The MAX5077 is 100% tested at TA = TJ = +125°C.
PAGE 4
Typical Operating Characteristics (continued) (VCC = +12V, SEL1 = VCC, SEL2 = DGND, RRT = 124kΩ, NDRV1 = NDRV2 = open, CLK = open.) 10 CCLK = 30pF 10 8 6 4 8 6 4 256 RRT = 124kΩ 2 2 0 5 6 7 8 9 10 11 12 13 14 15 TA = -40°C 254 252 TA = +25°C 250 248 246 TA = +125°C 244 242 0 -50 -25 0 25 50 75 100 125 4 5 6 7 8 9 10 11 12 13 14 15 SUPPLY VOLTAGE (V) TEMPERATURE (°C) SUPPLY VOLTAGE (V) OSCILLATOR FREQUENCY vs. RRT NDRV FREQUENCY vs.
PAGE 5
Push-Pull FET Driver with Integrated Oscillator and Programmable Clock Output PIN NAME FUNCTION 1, 8 N.C. No Connection. Must be left unconnected. 2 SEL1 CLK Frequency Ratio Select Input. Use SEL1 and SEL2 to set fCLK to fNDRV_ frequency ratio (see Table 1). 3 CLK Synchronizing Clock Output. Clock output with a ±10mA peak current drive that can be used to synchronize an external PWM regulator. CLK/NDRV_ frequency has a 1x, 2x, or 4x ratio (see the Synchronizing Clock Output section). 4, 14 I.C.
PAGE 6
MAX5077 Push-Pull FET Driver with Integrated Oscillator and Programmable Clock Output Detailed Description The MAX5077 is a +4.5V to +15V push-pull, current-fed topology driver subsystem with an integrated oscillator for use in 48V module power supplies. The MAX5077 features a programmable accurate integrated oscillator with a synchronizing clock output that can be used to synchronize an external PWM stage. A single external resistor programs the internal oscillator frequency from 50kHz to 1.5MHz.
PAGE 7
Push-Pull FET Driver with Integrated Oscillator and Programmable Clock Output Supply Bypassing Pay careful attention to bypassing and grounding the MAX5077. Peak supply and output currents may exceed 3A when driving large MOSFETs. Ground shifts due to insufficient device grounding may also disturb other circuits sharing the same ground-return path. Any series inductance in the VCC, NDRV1, NDRV2, and/or GND paths can cause noise due to the very high di/dt when switching the MAX5077 with any capacitive load.
PAGE 8
Push-Pull FET Driver with Integrated Oscillator and Programmable Clock Output MAX5077 Pin Configuration Chip Information TRANSISTOR COUNT: 1335 PROCESS: BiCMOS TOP VIEW N.C. 1 SEL1 2 CLK 3 I.C. 4 14 I.C. 13 SEL2 12 VCC MAX5077 RT 5 11 NDRV2 10 NDRV1 AGND 6 9 PGND DGND 7 8 N.C. *EP TSSOP *EXPOSED PADDLE CONNECTED TO DGND.
PAGE 9
Push-Pull FET Driver with Integrated Oscillator and Programmable Clock Output TSSOP 4.4mm BODY.EPS XX XX PACKAGE OUTLINE, TSSOP, 4.40 MM BODY, EXPOSED PAD 21-0108 E 1 1 Revision History Pages changed at Rev 1: 1, 2, 5, 6, 9 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.