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dc1748af

DEMO MANUAL DC1748A

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Supply Range LTM2883-5 4.5 5 5.5 V

LTM2883-3 3.0 3 3.6 V

CC2

Regulated Output Voltage 4.75 5 5.25 V

Adjustable Output Voltage Range 3.0 5.5 V

Maximum Load Current 20 mA

Regulated Output Voltage 12 12.5 13 V

Adjustable Output Voltage Range 1.22 14 V

Maximum Load Current 20 mA

–

Regulated Output Voltage –12 –12.5 –13 V

Adjustable Output Voltage Range –1.22 14 V

Maximum Load Current 15 mA

MAX

Maximum Data Rate

DI1 → O1, Ix → DOx, C

= 10pF

10 MHz

LTM2883-S, Bidirectional Communication

LTM2883-S, Unidirectional Communication

MHz

LTM2883-I 400 kHz

IORM

Maximum Working Insulation Voltage GND to GND2 560

400

RMS

Common Mode Transient Immunity 30 kV/µs

DESCRIPTION

LTM2883 SPI/Digital or

C µModule Isolator with Adjustable ±12.5V

and 5V Regulated Power

Demonstration circuit 1748A is a serial peripheral interface

bus (SPI) or inter-IC bus (I

C) SPI/digital or I

C µModule

isolator with adjustable ±12.5V and 5V regulated power

featuring the LTM2883. The demo circuit features an EMI

optimized circuit conﬁ guration and printed circuit board

layout. All components are integrated into the µModule

isolator. The demo circuit operates from a single external

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

PERFORMANCE SUMMARY

= 25°C)

supply on V

. The part generates output voltages on V

CC2

, and V

–

, which may be adjusted by external program-

ming resistors. It communicates all necessary signaling

across the isolation barrier through LTC’s isolator µModule

technology.

Design ﬁ les for this circuit board are available at

http://www.linear.com/demo

Summary of content (10 pages)

PAGE 1
DEMO MANUAL DC1748A LTM2883 SPI/Digital or I2C µModule Isolator with Adjustable ±12.5V and 5V Regulated Power DESCRIPTION Demonstration circuit 1748A is a serial peripheral interface bus (SPI) or inter-IC bus (I2C) SPI/digital or I2C μModule isolator with adjustable ±12.5V and 5V regulated power featuring the LTM2883. The demo circuit features an EMI optimized circuit conﬁguration and printed circuit board layout. All components are integrated into the μModule isolator.
PAGE 2
DEMO MANUAL DC1748A OPERATING PRINCIPLES The LTM2883 contains an isolated DC/DC conversion system, including a boost converter and inverting charge pump, with multiple LDO’s to deliver power to the three output voltage rails from VCC. Isolation is maintained by the separation of GND and GND2 where signiﬁcant operating voltages and transients can exist without affecting the operation of the LTM2883. The logic side ON pin enables or shuts down the LTM2883.
PAGE 3
DEMO MANUAL DC1748A OPERATING PRINCIPLES EMI performance is shown in Figure 1, measured using a Gigahertz Transverse Electromagnetic (GTEM) cell and method detailed in IEC 61000-4-20, “Testing and Measurement Techniques – Emission and Immunity Testing in Transverse Electromagnetic Waveguides”. Table 3. VOLTAGE RAIL RESISTOR TO REDUCE OUTPUT V+ R5 = 150k • (V+ – 1.22)/(12.5 – V+) V– R6 = 150k • (1.22 + V–)/(–12.5 – V–) VCC2 R7 = 110k • (VCC2 – 0.
PAGE 4
DEMO MANUAL DC1748A QUICK START PROCEDURE Demonstration circuit 1748A is easy to set up and evaluate the performance of the LTM2883. Refer to Figure 2 for proper measurement equipment setup and follow the procedure below. NOTE: When measuring the input or output voltage ripple or high speed signals, care must be taken to avoid a long ground lead on the oscilloscope probe. 1. Install JP1 in the ON (default) position. 2. With power off, connect the input power supply to VCC and GND on pin header J1. 3.
PAGE 5
DEMO MANUAL DC1748A PCB LAYOUT Layer 1. Top Layer Layer 2.
PAGE 6
DEMO MANUAL DC1748A PCB LAYOUT Layer 3. Signal Layer Layer 4.
PAGE 7
DEMO MANUAL DC1748A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 U1-A IC, LTM2883CY-3S Linear Technology LTM2883CY-3S#PBF 1 U1-B IC, LTM2883CY-5S Linear Technology LTM2883CY-5S#PBF 1 U1-C IC, LTM2883CY-3I Linear Technology LTM2883CY-3I#PBF 1 U1-D IC, LTM2883CY-5I Linear Technology LTM2883CY-5I#PBF Hardware/Components (For Demo Board Only) 2 1 C1 Capacitor, Tantalum 10μF 10V 20% TAJA AVX TAJA106M010RNJ 3 1 C2 Capacitor,
PAGE 8
DEMO MANUAL DC1748A SCHEMATIC DIAGRAM (DC1748A-A/DC1748A-B) dc1748af 8
PAGE 9
DEMO MANUAL DC1748A SCHEMATIC DIAGRAM (DC1748A-C/DC1748A-D) dc1748af Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
PAGE 10
DEMO MANUAL DC1748A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use.