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MAX845

Isolated Transformer Driver for PCMCIA Applications

Internal Power MOSFETs Save Space and Deliver 750mW

Overview

Technical Documents

Ordering Info

Status

Active: In Production.

Description

The MAX845 provides an isolated power supply small enough to fit in thin PCMCIA cards and space-sensitive applications. It drives a low-profile center-tapped transformer primary from a 5V or 3.3V DC power supply. The secondary can be wound to provide any isolated positive or negative voltage at powers up to 750mW.

The MAX845 consists of an oscillator followed by a toggle flip-flop. The flip-flop generates two 50% duty-cycle square waves, which are complementary at half the oscillator frequency (450kHz, min). These two signals drive the ground-referenced N-channel power switches. Internal circuitry ensures break-before-make action between the two switches.

A low-power shutdown disables both the switches and the oscillator, reducing power consumption. An evaluation kit (MAX845EVKIT-MM) is available to evaluate low-profile 5V 40mA and 5V 100mA applications.

Data Sheet

Download	Rev 4	(PDF, 224kB)
E-Mail

An evaluation kit is available: MAX845EVKIT

Key Features

Transformer Driver for Ultra-Thin 5V-µs Transformers
Isolated DC-to-DC Power Supply for PCMCIA Applications
450kHz Minimum Switching Frequency
Ultra-Low Input Supply Current Ripple
Single +5V or +3.3V Supply
5µW Low-Power Shutdown Mode
8-Pin SO and µMAX Packages
Low Output Ripple Permits Miniature Output Capacitors

Applications/Uses

Bridge Ground Differentials
Isolated Data Acquisition
Isolated Interface Power Supply
Low-Power LAN Networks
Medical Equipment
Noise-Immunity Communications Interface
PCMCIA Modem Cards
Process Control

Key Specifications:

Isolated Power Supplies

Part Number

V_IN
(V)

Topology

Feedback

Freq.
(kHz)

I_CC
(mA)

Oper. Temp.
(°C)

Budgetary Price

min

max

min

max

See Notes

MAX845

2.5

Push-Pull

Open Loop

860

1.1

-40 to +85

$1.76 @1k

See All Isolated Power Supplies (20)

Pricing 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.

Diagram

Typical Operating Circuit

Application Notes

Application Note 998		5V Step-Down Converter Has Transformer-Isolated Feedback
Application Note 1096		Transformer-Driver IC Controls Bidirectional Switch
Application Note 3465		Simple Power-FET Driver is Isolated and DC-Coupled
Application Note 3754		Single-Wire Serial Bus Carries Isolated Power and Data
Application Note 4432		Isolated Temperature Sensor
Application Note 4568		Bipolar DC-Voltage Detector Offers Sensitivity and Precision
Brochure 5088		36V H-Bridge Transformer Driver Provides Isolated Power for Meters

Reliability Reports

Reliability Report:	MAX845.pdf
Show FIT data for:

Software/Models

none

Ordering Information

Filters:

Part Number:

Package:

Temperature:

Tape and Reel

Sample

Part Number	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX845C/D			Active	DICE SALES;NA pin;DICE; Land Pattern: Not Applicable Use pkgcode/variation: DICE*		See data sheet
MAX845ESA			Active	SOIC(N);8 pin;30.9 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0096 (PDF) Use pkgcode/variation: S8-4*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX845ESA+			Active	SOIC(N);8 pin;30.9 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0096 (PDF) Use pkgcode/variation: S8+4*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX845ESA+T			Active	SOIC(N);8 pin;30.9 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0096 (PDF) Use pkgcode/variation: S8+4*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX845ESA-T			Active	SOIC(N);8 pin;30.9 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0096 (PDF) Use pkgcode/variation: S8-4*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX845ESA/GH9			Active	SOIC(N);8 pin;30.9 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0096 (PDF) Use pkgcode/variation: S8-4*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX845ESA/GH9-T			Active	SOIC(N);8 pin;30.9 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0096 (PDF) Use pkgcode/variation: S8-4*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX845EUA			Active	µMAX;8 pin;16.2 mm² Outline Drawing:21-0036 (PDF) Land Pattern: 90-0092 (PDF) Use pkgcode/variation: U8-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX845EUA+			Active	µMAX;8 pin;16.2 mm² Outline Drawing:21-0036 (PDF) Land Pattern: 90-0092 (PDF) Use pkgcode/variation: U8+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX845EUA+T			Active	µMAX;8 pin;16.2 mm² Outline Drawing:21-0036 (PDF) Land Pattern: 90-0092 (PDF) Use pkgcode/variation: U8+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
Part Number	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX845EUA-T			Active	µMAX;8 pin;16.2 mm² Outline Drawing:21-0036 (PDF) Land Pattern: 90-0092 (PDF) Use pkgcode/variation: U8-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis

Notes:

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product Naming Conventions.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

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Evaluation Kits

MAX845EVKIT

Evaluation Kit for the MAX845

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