Freescale Semiconductor
Advance Information
Document Number: 34726
Rev. 1.0, 5/2008
300mA High Efficiency Low
Quiescent Current Synchronous
Buck Regulator With Z-mode
The 34726 is a high efficiency, low quiescent current (I
Q
), synchro-
nous buck regulator, implementing Freescale’s innovative Z-mode ar-
chitecture. Freescale’s Z-mode architecture greatly improves the ripple
performance during light load currents, but still maintains a low quies-
cent current of 65uA, at no load in “Sleepy” Z-mode.
The 34726 accepts an input voltage in the range of 2.7 to 5.5V,
making it ideally suited for single cell Li-Ion based applications. Factory
preset output voltages, ranging from 0.8V to 3.3V, reduce the number
of required auxiliary components. The part is able to provide 300mA of
continuous load current across the input and the output voltage ranges.
The 34726 switches at 2.0MHz to allow the use of small, surface
mount inductors and capacitors to save precious board space.
The 34726 is available in the small, space saving, and low cost, 2x2
UDFN-8 packages. The part is guaranteed for operation over the -25°C
to 85°C temperature range.
Features
• 94% peak efficiency
• 2.0MHz switching frequency
• 2.7V to 5.5V input voltage range
• Automatic transition to energy saving light load Z-mode (low ripple)
• Fixed output voltage options from 0.8 to 3.3V
• 65µA quiescent current during sleepy Z-mode
• 300mA maximum continuous output current
• Internal 2.0ms soft start
• Thermal and over-current protection
• 0.1µA quiescent current in shutdown (disabled)
• Ultra thin 2x2 UDFN package
• Pb-free packaging designated by suffix code FC
34726
2.7V ~ 5.5V
C
IN
VIN
SW
34726
POWER MANAGEMENT IC
Bottom View
FC SUFFIX (PB-FREE)
98ASA10787D
8-PIN UDFN
2X2
ORDERING INFORMATION
Device
MC34726AFC/R2
MC34726BFC/R2
MC34726CFC/R2
-25°C to 85°C
8-UDFN
Temperature
Range (T
A
)
Package
L1
0.8 - 3.3V *
300mA
FB
ON
OFF
EN
GND
C
OUT
*Programmable
See table 1
Figure 1. 34726 Typical Operating Circuit
* This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2008. All rights reserved.
DEVICE VARIATIONS
DEVICE VARIATIONS
Table 1. Device Variations
Freescale Part No.
MC34726AFC
MC34726BFC
MC34726CFC
V
IN
Range
2.7 - 5.5V
2.7 - 5.5V
3.6 - 5.5V
Output Voltage
(1)
1.2V
1.8V
3.3V
Maximum Load Current
300mA
300mA
300mA
Switch Frequency (MHz)
(2)
2.0
2.0
2.0
Notes
1. Output voltages of: 0.8V, 0.9V, 1.0V, 1.1V, 1.3V, 1.4V, 1.5V, 1.85V, 2.0V, 2.5V options available on request. Contact Freescale sales.
2. Factory programmable at 2.0MHz or 4.0Mhz. Contact Freescale sales for availability of the 4.0MHz functionality.
34726
2
Analog Integrated Circuit Device Data
Freescale Semiconductor
PIN CONNECTIONS
PIN CONNECTIONS
VIN
GND
GND
EN
1
2
3
4
2x2 UDFN-8 (Non EP)
8
7
6
5
SW
SW
NC
FB
Transparent
Top View
Figure 3. 34726 Pin Connections
Table 2. 34726 Pin Definitions
A functional description of each pin can be found in the Functional Pin Description section beginning on
page 10.
Pin Number
1
2
3
4
5
6
7
8
Pin Name
VIN
GND
GND
EN
FB
NC
SW
SW
Pin Function
Input
Ground
Ground
Input
Input
N/A
Output
Output
Formal Name
Supply Voltage Input
Ground
Ground
Enable
Feedback Input
No Connection
Switching Node
Switching Node
Power input
Ground
Low noise ground
Active high enable input
Feedback of the output voltage
Internally not connected. Connect to GND externally
This terminal connects to the output inductor
This terminal connects to the output inductor
Definition
34726
4
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
Table 3. Maximum Ratings
All voltages are with respect to ground unless otherwise noted. Exceeding these ratings may cause a malfunction or
permanent damage to the device.
Ratings
ELECTRICAL RATINGS
All pins voltages
ESD Voltage
(1)
Human Body Model (HBM)
Machine Model (MM)
THERMAL RATINGS
Operating Ambient Temperature Range
Storage Temperature Range
Maximum Lead Temperature
(2),(3)
Junction Temperature
Operating Junction Temperature
Maximum Junction Temperature
Thermal Resistance
(4)
Junction-to-Case
Junction-to-Ambient
Power Dissipation
Continuous (Derate 3.0mW/°C and over T
A
= 70°C)
R
θJC
R
θJA
P
D
0.5
104
122
W
T
A
T
STG
T
PPRT
T
J
125
+150
°C/W
-25 to +85
-25 to +150
Note 3
°C
°C
°C
°C
V
IN
, V
EN
, V
FB
,
V
SW
V
ESD
±2000
±200
-0.3 to 6.0
V
V
Symbol
Value
Unit
Notes
1. ESD testing is performed in accordance with the Human Body Model (HBM) (C
ZAP
= 100pF, R
ZAP
= 1500Ω), and the Machine Model
(MM) (C
ZAP
= 200pF, R
ZAP
= 0Ω).
2.
3.
Pin soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may
cause malfunction or permanent damage to the device.
Freescale’s Package Reflow capability meets Pb-free requirements for JEDEC standard J-STD-020C. For Peak Package Reflow
Temperature and Moisture Sensitivity Levels (MSL). Go to www.freescale.com, search by part number [e.g. remove prefixes/suffixes
and enter the core ID to view all orderable parts. (i.e. MC33xxxD enter 33xxx), and review parametrics.
Device mounted on the Freescale EVB test board per JEDEC DESD51-2.
4.
34726
Analog Integrated Circuit Device Data
Freescale Semiconductor
5
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