Datasheet

ManualsBrandsANALOG DEVICES ManualsPMICsPMIC - DC/DC voltage regulator Push-pull QSOP 16

Isolated Switching Regulator

With Integrated Feedback

Data Sheet

ADuM3070

Rev. 0

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FEATURES

Isolated PWM feedback with built in compensation

Primary side transformer driver for up to 2.5 W output power

with 5 V input voltage

Regulated adjustable output: 3.3 V to 24 V

Up to 80% efficiency

200 kHz to 1 MHz adjustable oscillator

Soft start function at power-up

Pulse-by-pulse overcurrent protection

Thermal shutdown

2500 V rms isolation

High common-mode transient immunity: >25 kV/µs

16-lead QSOP package

High temperature operation: 105°C

APPLICATIONS

Power supply startup bias and gate drives

Isolated sensor interfaces

Process controls

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GENERAL DESCRIPTION

The ADuM3070

isolator is a regulated dc-to-dc isolated power

supply controller with an internal MOSFET driver. The dc-to-

dc controller has an internal isolated PWM feedback from the

secondary side based on the iCoupler® chip scale transformer

technology and complete loop compensation. This eliminates

the need to use an optocoupler for feedback and compensates

the loop for stability.

The ADuM3070 isolator provides a more stable output voltage and

higher efficiency compared to unregulated isolated dc-to-dc power

supplies. The fully integrated feedback and loop compensation

in a small QSOP package provides a smaller form factor than any

discrete solution. The regulated feedback provides a relatively flat

efficiency curve over the full output power range. The ADuM3070

enables a dc-to-dc converter with a 3.3 V to 24 V isolated output

voltage range from either a 5.0 V or a 3.3 V input voltage, with

an output power of up to 2.5 W.

Protected by U.S. Patents 5,952,849; 6,873,065; and 7075 329 B2. Other patents are pending.

ADuM3070

10437-001

PRIMARY

CONVERTER/

DRIVER

SECONDARY

CONTROLLER

INTERNAL

FEEDBACK

DD2

REG

DD1

ISO

DDA

X2X1

GND

REG

RECT

NOTES

1. V

DD1

IS THE POWER SUPPLY FOR THE PUSH-PULL TRANSFORMER.

2. V

DDA

IS THE POWER SUPPLY OF SIDE 1 OF THE ADuM3070.

Summary of content (20 pages)

PAGE 1
FEATURES Isolated PWM feedback with built in compensation Primary side transformer driver for up to 2.5 W output power with 5 V input voltage Regulated adjustable output: 3.
PAGE 2
ADuM3070 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Pin Configuration and Function Descriptions..............................8 Applications ....................................................................................... 1 Typical Performance Characteristics ..............................................9 Functional Block Diagram ..............................................................
PAGE 3
Data Sheet ADuM3070 SPECIFICATIONS ELECTRICAL CHARACTERISTICS—5 V PRIMARY INPUT SUPPLY/5 V SECONDARY ISOLATED SUPPLY 4.5 V ≤ VDD1 = VDDA ≤ 5.5 V, VDD2 = VREG = VISO = 5.0 V, fSW = 500 kHz, all voltages are relative to their respective grounds, see the application schematic in Figure 31. All minimum/maximum specifications apply over the entire recommended operating range, unless otherwise noted. All typical specifications are at TA = 25°C, VDD1 = VDDA = 5.0 V, VDD2 = VREG = VISO = 5.0 V. Table 1.
PAGE 4
ADuM3070 Data Sheet ELECTRICAL CHARACTERISTICS—5 V PRIMARY INPUT SUPPLY/3.3 V SECONDARY ISOLATED SUPPLY 4.5 V ≤ VDD1 = VDDA ≤ 5.5 V, VDD2 = VREG = VISO = 3.3 V, fSW = 500 kHz, all voltages are relative to their respective grounds, see the application schematic in Figure 31. All minimum/maximum specifications apply over the entire recommended operating range, unless otherwise noted. All typical specifications are at TA = 25°C, VDD1 = VDDA = 5.0 V, VDD2 = VREG = VISO = 3.3 V. Table 3.
PAGE 5
Data Sheet ADuM3070 PACKAGE CHARACTERISTICS Table 5. Parameter RESISTANCE Input to Output 1 CAPACITANCE Input to Output1 THERMAL IC Junction-to-Ambient Thermal Resistance 2 Thermal Shutdown Threshold Hysteresis 1 2 Symbol RI-O Min Typ 1012 Max Unit Ω Test Conditions/Comments f = 1 MHz CI-O 2.2 pF θJA 76 °C/W TSSD TSSD-HYS 150 20 °C °C TJ rising The device is considered a 2-terminal device: Pin 1 to Pin 8 is shorted together, and Pin 9 to Pin 16 is shorted together.
PAGE 6
ADuM3070 Data Sheet DIN V VDE V 0884-10 (VDE V 0884-10) INSULATION CHARACTERISTICS These isolators are suitable for reinforced electrical isolation only within the safety limit data. Protective circuits ensure maintenance of the safety data. The asterisk (*) marking on packages denotes DIN V VDE V 0884-10 approval. Table 8.
PAGE 7
Data Sheet ADuM3070 ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Table 11. Maximum Continuous Working Voltage Supporting 50-Year Minimum Lifetime1 Table 10. Parameter Storage Temperature Range (TST) Ambient Operating Temperature Range (TA) Supply Voltages VDDA, VDD21, 2 VREG, X1, X21 Common-Mode Transients3 Rating −55°C to +150°C −40°C to +105°C Parameter AC Voltage Bipolar Waveform −0.5 V to +7.0 V −0.5 V to +20.
PAGE 8
ADuM3070 Data Sheet PIN CONFIGURATION AND FUNCTION DESCRIPTIONS X1 1 16 VREG *GND1 2 15 GND2* NC 3 ADuM3070 14 VDD2 X2 4 TOP VIEW (Not to Scale) 13 FB TP 5 12 NC TP 6 11 NC VDDA 7 *GND1 8 10 OC 9 GND2* NOTES 1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN. 2. TP = TEST POINT. DO NOT CONNECT TO THIS PIN. 10437-003 *PIN 2 AND PIN 8 ARE INTERNALLY CONNECTED, AND CONNECTING BOTH TO GND1 IS RECOMMENDED.
PAGE 9
Data Sheet ADuM3070 TYPICAL PERFORMANCE CHARACTERISTICS 90 1500 1400 80 1300 1200 70 1100 EFFICIENCY (%) fSW (kHz) 1000 900 800 700 600 500 60 50 40 30 400 20 200 TA = –40°C TA = +25°C TA = +105°C 10 100 50 100 150 200 250 300 350 400 450 500 ROC (Ω) 0 80 80 70 70 60 60 EFFICIENCY (%) 90 50 40 30 fSW = 1MHz fSW = 700kHz fSW = 500kHz fSW = 200kHz 0 0 50 100 150 200 250 300 350 400 450 500 LOAD CURRENT (mA) 200 250 300 350 400 450 500 50 40 30 5V IN TO
PAGE 10
ADuM3070 Data Sheet 80 90 70 80 70 EFFICIENCY (%) 50 40 30 20 50 40 30 20 50 100 150 200 250 300 LOAD CURRENT (mA) 0 10437-034 0 0 TA = –40°C TA = +25°C TA = +105°C 10 Figure 10. Typical Efficiency at 3.3 V In to 5 V Out over Temperature with 1:3 Halo Transformer (TGSAD-290V6LF) at 500 kHz fSW 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 LOAD CURRENT (mA) 10437-011 TA = –40°C TA = +25°C TA = +105°C 10 Figure 13.
PAGE 11
Data Sheet ADuM3070 5.75 5 COUT = 47µF, L1 = 47µH 5.25 4.75 VISO (V) 4 VISO (V) 3 4.25 5.75 COUT = 47µF, L1 = 100µH 5.25 4.75 2 4.25 0 5 10 15 20 25 30 TIME (ms) 10437-014 0 ILOAD (A) LOAD = 10mA LOAD = 50mA LOAD = 500mA 1.0 10% LOAD 0.5 0 –2 0 2 4 90% LOAD 6 8 10 12 14 TIME (ms) Figure 16. Typical VISO Startup at 5 V In to 3.3 V Out with 10 mA, 50 mA, and 500 mA Output Load 10437-017 1 Figure 19.
PAGE 12
ADuM3070 4.0 COUT = 47µF, L1 = 100µH 14 2.5 12 1.0 0 2 4 6 8 10 12 14 Figure 22. Typical VISO Load Transient Load Response, 5 V In to 3.3 V Out at 10% to 90% Load of 500 mA Load at 500 kHz fSW with 0.1 µF Feedback Capacitor 4.0 VISO (V) COUT = 47µF, L1 = 100µH 14 2.5 12 0 –2 0 2 4 90% LOAD 6 8 10 12 14 Figure 23. Typical VISO Load Transient Response, 3.3 V In to 3.3 V Out at 10% to 90% of 250 mA Load at 500 kHz fSW 4.0 ILOAD (A) ILOAD (A) 3.0 1.
PAGE 13
Data Sheet ADuM3070 15.08 3.36 15.06 VISO (V) VISO (V) 15.04 3.32 3.28 15.02 15.00 14.98 14.96 3.24 14.94 10 0 –2 –1 0 1 2 TIME (µs) Figure 28. Typical VISO Output Ripple, 5 V In to 3.3 V Out at 500 mA Load at 500 kHz fSW VISO (V) 3.32 3.28 3.24 10 0 1 TIME (µs) 2 10437-023 X1 (V) 20 –1 0 –2 –1 0 1 TIME (µs) Figure 30. Typical VISO Output Ripple, 5 V In to 15 V Out at 100 mA Load at 500 kHz fSW 3.36 0 –2 10 Figure 29. Typical VISO Output Ripple, 3.3 V In to 3.
PAGE 14
ADuM3070 Data Sheet APPLICATIONS INFORMATION A minimum load current of 10 mA is recommended to ensure optimum load regulation. Smaller loads can generate excess noise on the output because of short or erratic PWM pulses. Excess noise generated from smaller loads can cause regulation problems, in some circumstances. COUT 47µF VDD1 V ISO CFB D2 VDD1 1 X1 16 VREG 2 GND1 15 GND2 3 NC 14 VDD2 VDD1 0.1µF 0.
PAGE 15
Data Sheet ADuM3070 TRANSFORMER DESIGN Transformers have been designed for use in the circuits shown in Figure 31, Figure 32, and Figure 33 and are listed in Table 13. The design of a transformer for the ADuM3070 can differ from some isolated dc-to-dc converter designs that do not regulate the output voltage.
PAGE 16
ADuM3070 Data Sheet Table 13. Transformer Reference Designs Part No.
PAGE 17
Data Sheet ADuM3070 The board layout shows enlarged pads for the GNDx pins (Pin 2 and Pin 8) on Side 1 and (Pin 9 and Pin 15) on Side 2. Implement large diameter vias from the pad to the ground planes and power planes to increase thermal conductivity and to reduce inductance. Multiple vias in the thermal pads can significantly reduce temperatures inside the chip. The dimensions of the expanded pads are left to the discretion of the designer and the available board space. Table 14.
PAGE 18
ADuM3070 Data Sheet POWER CONSIDERATIONS Soft Start Mode and Current-Limit Protection When the ADuM3070 first receives power from VDD1, it is in soft start mode, and the output voltage, VISO, is increased gradually while it is below the startup threshold. In soft start mode, to limit the peak current during VISO power-up, the primary converter gradually increases the width of the PWM signal.
PAGE 19
Data Sheet ADuM3070 OUTLINE DIMENSIONS 0.197 (5.00) 0.193 (4.90) 0.189 (4.80) 9 1 8 0.244 (6.20) 0.236 (5.99) 0.228 (5.79) 0.010 (0.25) 0.006 (0.15) 0.069 (1.75) 0.053 (1.35) 0.065 (1.65) 0.049 (1.25) 0.010 (0.25) 0.004 (0.10) COPLANARITY 0.004 (0.10) 0.158 (4.01) 0.154 (3.91) 0.150 (3.81) 0.025 (0.64) BSC SEATING PLANE 0.012 (0.30) 0.008 (0.20) 8° 0° 0.020 (0.51) 0.010 (0.25) 0.050 (1.27) 0.016 (0.