RICOH RN5T562 Technical data
Step-down DC/DC with LDOs
RN5T562
Development Specifications
Rev.1.5
2009/05/14
RICOH COMPANY, LTD.
Electronic Devices Company
This specification is subject to change without notice.
RN5T562 Step-down DC/DC with LDOs
Table of Contents
1. Outline........................................................................................................................................... 3
2. Feature........................................................................................................................................... 3
3. Application.................................................................................................................................... 3
4. Ordering Information .................................................................................................................... 3
5. Block Diagram .............................................................................................................................. 4
6. Pin Configuration.......................................................................................................................... 4
7. Pin Description.............................................................................................................................. 5
8. Electrical Characteristics............................................................................................................... 6
8.1 Absolute Maximum Ratings .................................................................................................................... 6
8.2 Recommended Operating Conditions........................................................................................................ 6
8.3 Step-down DC/DC Converter Electrical Characteristics ............................................................................. 7
8.4 LDO1 Electrical Characteristics ............................................................................................................... 8
8.5 LDO2 Electrical Characteristics ............................................................................................................... 9
8.6 UVLO (Under Voltage Lock Out) Electrical Characteristics..................................................................... 10
8.7 Thermal Shutdown Circuit Electrical Characteristics ............................................................................... 10
8.8 DC Electrical Characteristics ................................................................................................................. 11
9. ON/OFF Control of LDOs and DC/DC ...................................................................................... 11
10. Step-down DC/DC Converter .................................................................................................. 12
10.1 Step-down DC/DC Converter Output Voltage Setting.............................................................................. 12
11. Typical Application and Application Hints ............................................................................. 13
12. Appendix.................................................................................................................................. 14
12.1 Reference Data of Step-down DC/DC Converter ..................................................................................... 14
13. Package Information ................................................................................................................ 16
©2009 Rev.1.5 Page 2
RN5T562 Step-down DC/DC with LDOs
1. Outline
RN5T562 integrates CMOS-based step-down DC/DC converter and two low dropout regulators (LDOs) with low
supply current. A low ripple, high efficiency step-down DC/DC converter can be easily composed of this IC with
some external components such as inductor, capacitors and resistor. The self-oscillation frequency is up to 2MHz
and it allows DCDC to use small inductor and capacitor.
Output enable/disable of regulators is individually controllable through external pins. In addition, this IC has the
under voltage lockout function (UVLO), which powers off all the regulators with 2.20V (Typ.) UVLO threshold.
Also, RN5T562 has Thermal shutdown circuit which turns off all the regulators in the overheated state.
2. Feature
• Range of Input Voltage .............. 3.1V ~ 4.5V (DC/DC), 1.746V(1.8V-3.0%) ~ 4.5V (LDOs)
• Built-in Soft-start Function for DCDC
• Maximum Output Current.......... 500mA (DC/DC), 200mA (LDOs)
• Accuracy Output Voltage .......... ±3.0% (LDOs Output)
• Output Voltage (LDO1) ............ Settable in 0.05V step in range of 1.2V to 3.3V
• Output Voltage (LDO2) ............ Settable in 0.05V step in range of 1.2V to 3.3V
• Output Voltage (DC/DC) .......... Setting external resistance ratio in the range of 0.9V to 2.0V
• Thermal Shutdown Circuit
• UVLO
• Package ..................................... QFN 16pins, 3mm×3mm, t=0.8mm
• Process ...................................... CMOS
3. Application
• Power source for DMB.
• Power source for battery-powered equipment.
4. Ordering Information
RN5T562-XXXYYY
XXX : LDO1 Output Voltage.
YYY : LDO2 Output Voltage.
For example.
RN5T562-150180 : LDO1=1.50V, LDO2=1.80V.
©2009 Rev.1.5 Page 3
RN5T562 Step-down DC/DC with LDOs
5. Block Diagram
The block diagram of the device is shown below.
6. Pin Configuration
QFN 16pins, 3mm×3mm, t=0.8mm
GND2
VFB
NC
NC
Fig 5-1 Block Diagram
LX
11
TOP
VIEW
2
VIN1
PGND
10
3
VIN2
PVIN
12
13
14
15
16
1
VO1
DCON
9
8
7
6
5
4
VO2
LDO2ON
LDO1ON
VIN3
GND1
Fig 6-1 Pin Configuration
©2009 Rev.1.5 Page 4
RN5T562 Step-down DC/DC with LDOs
7. Pin Description
No. Name I/O
1 VO1
2 VIN1
3 VIN2
4 VO2
5 GND1
6
7 LDO1ON
8 LDO2ON
9 DCON
10 PGND
11
12
13 GND2
14 VFB
15 NC - Non-connect. Connect to GND.
16 NC - Non-connect. Connect to GND.
VIN3
LX
PVIN
PWR
PWR
GND
PWR
GND
PWR
GND
Output voltage of LDO1.
O
Power supply for LDO1.
Power supply for LDO2.
Output voltage of LDO2.
O
GND for LDO block, UVLO, and TSHUT.
Power supply for DC/DC converter control block, UVLO, and
TSHUT.
Input of LDO1 for ON/OFF.
I
Input of LDO2 for ON/OFF.
I
DC/DC ON/OFF control.
I
GND for DC/DC converter.
DC/DC converter switch output.
O
Power supply for DC/DC converter driver.
GND for DC/DC converter control block.
Output voltage feedback input of DCDC converter.
I
Function Notes
Table 7-1 Pin Description
©2009 Rev.1.5 Page 5
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