ams Datasheet Page 1
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AS3729B
8A Power Stage
The AS3729B is a companion power stage, intended to be used
with AS372x products.
It cannot be used without a DC/DC controller. It contains the
power FETs for 2 phases and is capable to handle output
currents of 4A per phase.
Ordering Information and Content Guide appear at end of
datasheet.
Key Benefits & Features
The benefits and features of AS3729B, 8A Power Stage are listed
below:
Figure 1:
Added Value of Using AS3729B
Applications
This device is a high current dual-phase DC/DC and ideal for:
•Mobile phones
•Tablets
•Notebooks
Benefits Features
•Support for single or dual phase operation •2 phases with separate control input
•2 x 4A output stages are running up to
2.7MHz
•Separate power NMOS & PMOS for 4A per phase
•Separate coil current feedback per phase
•Stand-Alone zero-crossing operation
•Over-temperature protection •Integrated temperature monitoring
•Cost effective, small package •WL-CSP16: 1.615mm x 1.615mm, 0.4mm pitch
General Description
Page 2 ams Datasheet
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AS3729B − General Description
Block Diagram
The functional blocks of this device are shown below:
Figure 2:
AS3729B Block Diagram
AS3729B Block Diagram: This figure shows the block diagram of the DC/DC controller inside the Main PMIC and
the AS3729B Power Stage with all relevant system components.
ramp S
PWM
Logic
Vov_current
Current sense RCSNS
VRef
error ota
ov_curr
PWM
clk
VSUP
FB
VSS
Logic
Isense
Zcomp
Pgate
Ngate
1uH 47uF
TEMP
CTRL1CTRL1
CTRL2
VSUP
LX1
PVSS
ams Datasheet Page 3
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AS3729B − Pin Assignment
Figure 3:
16 Balls WL-CSP with 0.4mm Pitch
Figure 4:
Pin Description
Pin Assignments: Shows the top view
pin assignment of the AS3729B
Pin Number Pin Name Description
A1 CTRL1 Control IO for phase 1
B1 TEMP On/Off control and temperature feedback
C1 AGND Analog ground
D1 CTRL2 Control IO for phase 2
A2, B2 VSUP Phase 1 positive supply terminal
C2, D2 VSUP Phase 2 positive supply terminal
A3, B3 LX1 Phase 1 switching output to coil
C3, D3 LX2 Phase 2 switching output to coil
A4, B4 PVSS Phase 1 negative supply terminal
C4, D4 PVSS Phase 2 negative supply terminal
Pin Assignment
B1
TEMP
C2
VSUP
B2
VSUP
A3
LX1
A2
VSUP
A1
CTRL1
B4
PVSS
C3
LX2
A4
PVSS
B3
LX1
C4
PVSS
Pin A1
indicator
C1
AGND
D1
CTRL2 D2
VSUP D4
PVSS
D3
LX2
Page 4 ams Datasheet
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AS3729B − Absolute Maximum Ratings
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. These are stress
ratings only. Functional operation of the device at these or any
other conditions beyond those indicated under Electrical
Characteristics is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device
reliability.
Figure 5:
Absolute Maximum Ratings
Symbol Parameter Min Max Units Comments
Electrical Parameters
Supply voltage to ground 5V
pins -0.5 7.0 V Applicable for pins
VSUPx, LXx, CTRLx
Supply voltage to ground 3V
pins -0.5 5.0 V Applicable for pin
TEMP
Voltage difference between
ground terminals -0.5 0.5 V Applicable for pins
PVSS, AGND
Input current
(latch-up immunity) -100 100 mA Norm: JEDEC JESD78
Continuous Power Dissipation (TA = 70°C)
PTContinuous power dissipation 1 W PT (1) for WL-CSP16 package
(RTHJA ~ 55K/W)
Electrostatic Discharge
ESDHBM Electrostatic discharge HBM ±2 kV Norm:
JEDEC JESD22-A114F
Absolute Maximum Ratings
ams Datasheet Page 5
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AS3729B − Absolute Maximum Ratings
Note(s) and/or Footnote(s):
1. Depending on actual PCB layout and PCB used
2. The reflow peak soldering temperature (body temperature) is specified according IPC/JEDEC J-STD-020 “Moisture/Reflow Sensitivity
Classification for Nonhermetic Solid State Surface Mount Devices”
Temperature Ranges and Storage Conditions
TAOperating temperature -40 85 °C
RTHJA Junction to ambient thermal
resistance °C/W RTHJA typ. 55K/W
TJJunction temperature 125 °C
TSTRG Storage temperature range -55 125 °C
TBODY Package body temperature 260 °C Norm IPC/JEDEC J-STD-020 (2)
RHNC Relative humidity
(non condensing) 585 %
MSL Moisture sensitivity level 1 Represents an unlimited floor
life time
Symbol Parameter Min Max Units Comments
Page 6 ams Datasheet
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AS3729B − Electrical Characteristics
All limits are guaranteed. The parameters with min and max
values are guaranteed with production tests or SQC (Statistical
Quality Control) methods.
Figure 6:
Electrical Characteristics
Electrical Characteristics: Shows the Electrical Characteristics of the Step Down DC/DC Power Stage. VSUP =
3.8V, TA = 25°C (unless otherwise specified)
Note(s) and/or Footnote(s):
1. Maximum value only for pulsed peak current
2. MOS transistor only without package parasitic
Symbol Parameter Note Min Typ Max Unit
VIN Input voltage
Pin VSUPx 2.5 5.5 V
Pin CTRLx 0 5.5 V
Pin TEMP 0 3.6 V
ILIMIT Peak coil current limit Single phase 4.8 A
ILOAD Load current
single phase
Continuous load
current 03A
Peak load current 4 (1)
RPMOS
P-switch ON
resistance (2) Single phase 40 70 mΩ
RNMOS
N-switch ON
resistance (2) Single phase 20 35 mΩ
fSW Switching frequency Supplied by DC/DC
controller 1.3 3 MHz
IQ_force_PWM Quiescent current PWM TEMP pin high, force
PWM mode active 6.2 mA
IQ_low_power Quiescent current LP TEMP pin high, low
power mode active 21 μA
Ipower_off Power-Off current No current into pin
TEMP ±1 μA
Rdischarge Active discharge Single phase 16 Ω
Electrical Characteristics
ams Datasheet Page 7
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AS3729B − Typical Operating Characteristics
Figure 7:
Efficiency vs. Output Current for 2016 Coil Types
Figure 8:
Efficiency vs. Output Current for 2520 Coil Types
AS3729B Step Down DC/DC: Shows the
Efficiency of AS3729B of various coil
types in a 2016 package in dual and
combined mode. For the dual mode two
1uH coils are used and for the combined
mode one 470nH coil. VSUP = 3.7V,
VOUT = 1.2V, 1.35MHz operation,
TA = 25°C
AS3729B Step Down DC/DC: Shows the
Efficiency of AS3729B of various coil
types in a 2520 package in dual and
combined mode. For the dual mode two
1uH coils are used and for the combined
mode one 470nH coil. VSUP = 3.7V,
VOUT = 1.2V, 1.35MHz operation,
TA = 25°C
Typical Operating
Characteristics
60
65
70
75
80
85
90
95
0.01 0.1 1 10
Efficiency (%)
Output Current (A)
AS3729B 3V7-1V2 TFM201610GHM-1R0M dual (1.35MHz)
AS3729B 3V7-1V2 CITG201610GM1R0MWE dual (1.35MHz)
AS3729B 3V7-1V2 DFE201610P-1R0 dual (1.35MHz)
AS3729B 3V7-1V2 TFM201610GHM-R47M combined (1.35MHz)
AS3729B 3V7-1V2 CIGT201610HMR47MNE combined (1.35MHz)
AS3729B 3V7-1V2 DFE201610P-R47 combined (1.35MHz)
60
65
70
75
80
85
90
95
0.01 0.1 1 10
Efficiency (%)
Output Current (A)
AS3729B 3V7-1V2 VLS252010HBX-1R0 dual (1.35MHz)
AS3729B 3V7-1V2 DFE252010P-1R0 dual (1.35MHz)
AS3729B 3V7-1V2 VLS252010HBX-R47 combined (1.35MHz)
AS3729B 3V7-1V2 DFE252010P-R47M combined (1.35MHz)
Page 8 ams Datasheet
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AS3729B − Typical Operating Characteristics
Figure 9:
Efficiency vs. Output Current for Various TDK Coils
Figure 10:
Efficiency vs. Output Current for Various Toko Coils
AS3729B Step Down DC/DC: Shows the
Efficiency of AS3729B of various TDK
coils in dual and combined mode. VSUP
= 3.7V, VOUT = 1.2V, 1.35MHz operation,
TA = 25°C
AS3729B Step Down DC/DC: Shows the
Efficiency of AS3729B of various Toko
coils in dual and combined mode. VSUP
= 3.7V, VOUT = 1.2V, 1.35MHz operation,
TA = 25°C
60
65
70
75
80
85
90
95
0.01 0.1 1 10
Efficiency (%)
Output Current (A)
AS3729B 3V7-1V2 TFM201610GHM-1R0M dual (1.35MHz)
AS3729B 3V7-1V2 TFM201610GHM-R47M dual (1.35MHz)
AS3729B 3V7-1V2 TFM252010GHM-R47M dual (1.35MHz)
AS3729B 3V7-1V2 TFM201610GHM-R47M combined (1.35MHz)
AS3729B 3V7-1V2 TFM252010GHM-R47M combined (1.35MHz)
60
65
70
75
80
85
90
95
0.01 0.1 1 10
Efficiency (%)
Output Current (A)
AS3729B 3V7-1V2 DFE201610P-1R0 dual (1.35MHz)
AS3729B 3V7-1V2 DFE252010P-1R0 dual (1.35MHz)
AS3729B 3V7-1V2 DFE201610P-R47M dual (1.35MHz)
AS3729B 3V7-1V2 DFE252010P-R47M dual (1.35MHz)
AS3729B 3V7-1V2 DFE201610P-R47M combined (1.35MHz)
AS3729B 3V7-1V2 DFE252010P-R47M combined (1.35MHz)
ams Datasheet Page 9
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AS3729B − Application Information
Figure 11:
Typical Application Circuit
AS3729B Typical Application: This figure shows the connection of the DC/DC controller and the AS3729B Power
Stage.
External Components
Figure 12:
Step Down DC/DC Power Stage External Components
External Components: Shows the recommended values of the needed external components of the Step Down
DC/DC Power Stage
Symbol Parameter Note Min Typ Max Unit
External Components per Phase
CFB Output Capacitor
Ceramic X5R or X7R, high
performance 64 82 μF
Ceramic X5R or X7R, cost
optimized 32 47 μF
CVSUP Input Capacitor Ceramic X5R or X7R 6 10 μF
LInductor 5A rated, 1.3MHz operation,
low RON 0.5 1 μH
Application Information
VSUP
TEMP
CTRL1
CTRL2
LX2
LX1
PVSS
PVSS
1uH
1uH FB_SDx
Vout (0.6-1.5V@8A)
DVM, 10mV steps
47uF
VSUP
10uF
10uF
47uF
AS3729B
DC/DC
0.6 – 1.5V
8A
1.3MHz FB_SDx
CTRL2_SDx
CTRL1_SDx
TEMP_SDx
Page 10 ams Datasheet
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AS3729B − PCB Layout
Figure 13:
Layout Guidelines
Layout Guidelines: This figure shows the recommended layout and placement of the external components for
the 2-phase AS3729B Power Stage
PCB Layout
Vout
L1
CTRL1
TEMP
CTRL2
FB
GND
CIN1
CIN2
COUT1
COUT2
L2
3729B
XXXX
ams Datasheet Page 13
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AS3729B − Ordering & Contact Information
Figure 17:
Ordering Information
Buy our products or get free samples online at:
www.ams.com/ICdirect
Technical Support is available at:
www.ams.com/Technical-Support
Provide feedback about this document at:
www.ams.com/Document-Feedback
For further information and requests, e-mail us at:
ams_sales@ams.com
For sales offices, distributors and representatives, please visit:
www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
Ordering Code Package Marking Delivery Form Delivery Quantity
AS3729B-BWLM
16-pin WL-CSP 3729B Tape & Reel
500 pcs/reel
AS3729B-BWLT 12000 pcs/reel
Ordering & Contact Information
Page 14 ams Datasheet
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AS3729B − RoHS Compliant & ams Green Statement
RoHS: The term RoHS compliant means that ams AG products
fully comply with current RoHS directives. Our semiconductor
products do not contain any chemicals for all 6 substance
categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to
be soldered at high temperatures, RoHS compliant products are
suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br): ams Green
defines that in addition to RoHS compliance, our products are
free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous
material).
Important Information: The information provided in this
statement represents ams AG knowledge and belief as of the
date that it is provided. ams AG bases its knowledge and belief
on information provided by third parties, and makes no
representation or warranty as to the accuracy of such
information. Efforts are underway to better integrate
information from third parties. ams AG has taken and continues
to take reasonable steps to provide representative and accurate
information but may not have conducted destructive testing or
chemical analysis on incoming materials and chemicals. ams AG
and ams AG suppliers consider certain information to be
proprietary, and thus CAS numbers and other limited
information may not be available for release.
RoHS Compliant & ams Green
Statement
ams Datasheet Page 15
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AS3729B − Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141
Unterpremstaetten, Austria-Europe. Trademarks Registered. All
rights reserved. The material herein may not be reproduced,
adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner.
Devices sold by ams AG are covered by the warranty and patent
indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied,
or by description regarding the information set forth herein.
ams AG reserves the right to change specifications and prices
at any time and without notice. Therefore, prior to designing
this product into a system, it is necessary to check with ams AG
for current information. This product is intended for use in
commercial applications. Applications requiring extended
temperature range, unusual environmental requirements, or
high reliability applications, such as military, medical
life-support or life-sustaining equipment are specifically not
recommended without additional processing by ams AG for
each application. This product is provided by ams AG “AS IS”
and any express or implied warranties, including, but not
limited to the implied warranties of merchantability and fitness
for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any
damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interruption of business or
indirect, special, incidental or consequential damages, of any
kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation
or liability to recipient or any third party shall arise or flow out
of ams AG rendering of technical or other services.
Copyrights & Disclaimer
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AS3729B − Document Status
Document Status Product Status Definition
Product Preview Pre-Development
Information in this datasheet is based on product ideas in
the planning phase of development. All specifications are
design goals without any warranty and are subject to
change without notice
Preliminary Datasheet Pre-Production
Information in this datasheet is based on products in the
design, validation or qualification phase of development.
The performance and parameters shown in this document
are preliminary without any warranty and are subject to
change without notice
Datasheet Production
Information in this datasheet is based on products in
ramp-up to full production or full production which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade
Datasheet (discontinued) Discontinued
Information in this datasheet is based on products which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and
should not be used for new designs
Document Status
ams Datasheet Page 17
[v1-03] 2015-Sep-28 Document Feedback
AS3729B − Revision Information
Note(s) and/or Footnote(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
Changes from 1-01 (2014-Mar) to current revision 1-03 (2015-Sep-28) Page
1-01 (2014-Mar) to 1-02 (2015-Sep-21)
Content was updated to the latest ams design
Updated Figure 16 12
Updated Figure 17 13
1-02 (2015-Sep-21) to 1-03 (2015-Sep-28)
Updated Figure 14 11
Revision Information
Page 18 ams Datasheet
Document Feedback [v1-03] 2015-Sep-28
AS3729B − Content Guide
1 General Description
1 Key Benefits & Features
1 Applications
2 Block Diagram
3 Pin Assignment
4Absolute Maximum Ratings
6 Electrical Characteristics
7 Typical Operating Characteristics
9 Application Information
9 External Components
10 PCB Layout
11 Package Drawings & Markings
13 Ordering & Contact Information
14 RoHS Compliant & ams Green Statement
15 Copyrights & Disclaimer
16 Document Status
17 Revision Information
Content Guide
