MAX5068 High-Frequency, Current-Mode PWM Controller with Accurate Programmable Oscillator

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The MAX5068 is a high-frequency, current-mode, pulse-width modulation (PWM) controller that integrates all the building blocks necessary for implementing AC-DC or DC-DC fixed-frequency power supplies. Isolated or nonisolated power supplies are easily constructed using either primary- or secondary-side regulation. Current-mode control with leading-edge blanking simplifies control-loop design, and a programmable internal slope-compensation circuit stabilizes the current loop when operating at duty cycles above 50%. The MAX5068A/B limit the maximum duty cycle to 50% for use in single-ended forward converters. The MAX5068C/D/E/F allow duty cycles up to 75%. The MAX5068 features an accurate externally programmable oscillator that simplifies system design.

An input undervoltage lockout (UVLO) programs the input-supply startup voltage and ensures proper operation during brownout conditions.

A single external resistor programs the output switching frequency from 12.5kHz to 1.25MHz. The MAX5068A/B/C/E provide a SYNC input for synchronization to an external clock. The maximum FET-driver duty cycle is 50% for the MAX5068A/B and 75% for the MAX5068C/D/E/F. Programmable hiccup current limit provides additional protection under severe faults.

The MAX5068 is specified over the -40°C to +125°C automotive temperature range and is available in a 16-pin thermally enhanced TSSOP-EP package. Refer to the MAX5069 data sheet for dual FET-driver applications.

Warning: The MAX5068 is designed to work with high voltages. Exercise caution.

Key Features

Applications/Uses

Current-Mode Control with 47µA (typ) Startup Current
Resistor-Programmable ±4.5% Accurate Switching Frequency:
- 25kHz to 1.25MHz (MAX5068A/B)
- 12.5kHz to 625kHz (MAX5068C/D/E/F)
Rectified 85V_AC to 265V_AC or 36V_DC to 72V_DC Input (MAX5068A/C/D)
Input Directly Driven from 10.8V to 24V (MAX5068B/E/F)
Frequency Synchronization Input (MAX5068A/B/C/E)
Programmable Dead Time and Slope Compensation
Programmable Startup Voltage (UVLO)
Programmable UVLO Hysteresis (MAX5068A/B/D/F)
Integrating Fault Protection (Hiccup)
-40°C to +125°C Automotive Temperature Range
16-Pin Thermally Enhanced TSSOP-EP Package

	Industrial Power Conversion
	Isolated Telecom Power Supplies
	Networking System Power Supplies
	Server Power Supplies
	Universal-Input AC Power Supplies

Key Specifications: Isolated Power Supplies

Part Number

Application (Nominal Input Voltage)

V_IN (min) (V)

V_IN (max) (V)

Topology

Features

Control Loop

Feedback Type

Frequency (kHz)

Max. Duty Cycle (%)

Start-Up Current (max) (mA)

Operating Current, I_CC (max) (mA)

Gate Drive Current (A)

Current Sense Threshold (mV)

EV-Kit

RoHS Available

Package

Operating Temp. Range (°C)

Price^**

MAX5068

•	Networking (48V)

•	Telecom (36-72V)

•	Universal Off-line (90-240VAC)

10.8

Flyback
Single-Ended Forward

•	Adjustable Frequency

•	High Voltage Start-Up Circuit

•	Internal Error Amplifier

•	Synchronizable Freqeuncy

•	Thermal Shutdown

•

UVLO

Current Mode

Linear
Opto

1,250

50
75

0.09

2.5

314

Yes

TSSOP/16

-40 to +125

$1.28 @ 1k

See All Isolated Power Supplies (29)

Notes:
^**This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.