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R1273 Series
14A 34V Input Step-down DCDC Converter with Synchronous Rectifier

Product Specifications

The R1273 is a step-down DC/DC converter which can generate an output voltage of 0.7 V to 5.3 V by driving high- / low-side NMOSs. By the adoption of a unique current mode PWM architecture without an external current sense resistor, the R1273 can make up a stable DC/DC converter with high-efficiency even if adding low Ron MOSFETs and a low DCR inductor externally. And, by the frequency characteristics optimization with using external phase compensation capacitor, the R1273 can achieve a high-speed response to variations of input voltage and load current. The user-settable oscillation frequency is adjustable over a range of 250 kHz to 1 MHz by external resistors, and also can be synchronized to an external clock in a range of 250 kHz to 1 MHz. The R1273 supports three operating modes: Forced PWM mode, PLL_PWM mode, and PWM/VFM Auto-switching mode. These modes are selectable according to conditions of the MODE pin. Especially, the PWM/VFM Auto-switching mode can improve efficiency under light load conditions.
The R1273 can minimize the output voltage drop caused by an input voltage drop at cranking, with reducing the operating frequency (the lowest possible limit is a quarter of the frequency) so that the off-duty is reduced.
Protection functions include a current limit function, a hiccup-mode short-circuit protection (non-latch type), a thermal shutdown function, an UVLO (Under Voltage Lock Out) function, an OVD (Over Voltage Detection) function, a soft-start function, a low-inductor current shutdown function, and so on. Also, a power good function provide the status of output with using a power good (PGOOD) pin.
For EMI reduction, SSCG (Spread-Spectrum Clock Generator) for diffused oscillation frequency at the PWM operation is optionally available. The R1273 is available in QFN0505-32B package.

FEATURES

  Consumer Industrial Automotive
Operating Voltage (Maximum Rating) 4.0 V to 34 V (36 V)
Operating Temperature Range -40°C to 105°C -40°C to 125°C
Start-up Voltage 4.5 V
Output Voltage 0.7 V to 5.3 V
Feedback Voltage Tolerance 0.64 V ±1%
Consumption Current at No Load (at VFM mode) Typ. 15 µA
Adjustable Oscillation Frequency*1 250 kHz to 1 MHz
Synchronizable Clock Frequency*1 250 kHz to 1 MHz
Spreading Rate for SSCG Typ. ±3.6%
Minimum On-Time Typ. 100 ns
Minimum Off-Time Typ.120 ns (at regulation mode)
At dropout, actual minimum off-time is reduced.
Adjustable Soft-start Time*2 Typ. 500 µs
Functions Pre-bias Start-up
Anti-phase Clock Output
Thermal Shutdown Function Tj = 160°C (Typ.)
Under Voltage Lockout (UVLO) Function VCC = 3.3 V (Typ.)
Over Voltage Detection (OVD) Function FB pin voltage (VFB) + 10% (Typ.)
Detection/Release Hysteresis: FB pin voltage (VFB) x 3% (Typ.)
Under Voltage Detection (UVD) Function FB pin voltage (VFB) - 10% (Typ.)
Detection/Release Hysteresis: FB pin voltage (VFB) x 3% (Typ.)
Selectable Over-current Protection Hiccup-mode / Latch mode
Selectable Current Limit Threshold 50 mV / 70 mV / 100 mV
Hight-side / Low-side FET On-resistance Typ. 11.8 mΩ / 12.3 mΩ
Power Good Output NMOS Open-drain Output
Package QFN0505-32B

*1 The adjustable oscillation frequency range becomes 250 kHz ≤ fOSC ≤ 600 kHz when 0.7 V ≤ VOUT < 1.35V.
*2 500 µs (Typ.) as a lower limit with using an external capacitor. Otherwise, available the tracking function through the application of an external voltage.

APPLICATION INFORMATION

TYPICAL CHARACTERISTICS

Efficiency vs. Output Current

PIN DESCRIPTION

QFN0505-32B

QFN0505-32B5.0 mm × 6.0 mm
1 PGOOD
2 MODE
3, 25, *A AGND
4, 5, 6, 7, 8 PGND
9, 10, 11, 12, *C Lx
13, 18, 20, 22 NC
14, 15, 16, 17, 23, *B VIN
19 BST
21 VCC
24 CSS/TRK
26 CE
27 SENSE
28 VOUT
29 RT
30 COMP
31 FB
32 CLKOUT

R1273 Series for Consumer

APPLICATIONS

  • Power source for portable equipment such as PDA, DSC, Notebook PC.
  • Power source for office equipment such as printers and fax machines
  • Power source for 5V PSU or 2-cell or more Li-ion battery powered communication equipment, cameras, video instruments such as VCRs, camcorders
  • Power source for high voltage battery-powered equipment

Operating Temperature Range : -40°C to 105°C


SELECTION GUIDE

The function and setting for the ICs are selectable at the user’s request.

Product Name   Package Quantity per Reel
R1273LxxyA-E2 Consumer QFN0505-32B 1,000
  • xx … Select the combination of processing and function.
    00: Non-latch type hiccup mode, Disable SSCG
    01: Latch mode, Disable SSCG
    03: Latch mode, Enable SSCG
  • y … Select the current limit threshold voltage (Typ.).
    1: 50 mV
    2: 70 mV
    3: 100 mV

DOCUMENT/CONTACT

Purchase

Technical Support

Package *1 Reliability *2
QFN0505-32B R1273L

*1: The package file includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and land pattern (foot pattern).
*2: Reliability file includes a reliability test report and a reflow profile.


R1273 Series for Industrial

This product is a high-reliability semiconductor device for industrial application that has passed both the screening at high temperature and the reliability test with extended hours. Ricoh accommodates requests including the long-time operation and high temperature environment use.


APPLICATIONS

  • Industrial equipments such as FAs and smart meters
  • Equipments used under high-temperature conditions such as surveillance camera and vending machine.
  • Equipments accompanied by self-heating such as motor and lighting.

Operating Temperature Range : -40°C to 105°C


SELECTION GUIDE

The function and setting for the ICs are selectable at the user’s request.

Product Name   Package Quantity per Reel
R1273LxxyA-E2-Y Industrial QFN0505-32B 1,000
  • xx … Select the combination of processing and function.
    00: Non-latch type hiccup mode, Disable SSCG
    01: Latch mode, Disable SSCG
    03: Latch mode, Enable SSCG
  • y … Select the current limit threshold voltage (Typ.).
    1: 50 mV
    2: 70 mV
    3: 100 mV

DOCUMENT/CONTACT

Purchase

Technical Support

Package*1 Reliability*2
QFN0505-32B R1273L (-Y)

*1: The package file includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and land pattern (foot pattern).
*2: Reliability file includes a reliability test report and a reflow profile.


R1273 Series for Automotive

Ricoh is committed to providing a semiconductor device with the highest level of quality and reliability by restricting the device manufacturing only within Ricoh and the cooperative companies successfully passed our stringent inspections for automotive products. Ricoh established a traceability system and manages manufacturing information and logistics information from the warehouse.


Quality Ranks for Applications

Ricoh offers three different quality ranks for automotive products according to their application purposes.
R1273 Series offer products in Rank 3.

Rank 3: Automotive Accessories

  • Power source for car accessories such as car audio equipment, car navigation system, and ETC system

Operating Temperature Range : -40°C to 125°C


Tjmax 150°C

Unlike the rating of the products for consumer and industrial applications at Tjmax = 125°C, the products for automotive applications are rated at high temperature of Tjmax = 150°C. The power dissipation is also rated at high temperature.


SELECTION GUIDE

The function and setting for the ICs are selectable at the user’s request.

Product Name   Package Quantity per Reel
R1273LxxyA-E2-A AutomotiveAutomotive Accessories QFN0505-32B 1,000
  • xx … Select the combination of processing and function.
    00: Non-latch type hiccup mode, Disable SSCG
    01: Latch mode, Disable SSCG
    03: Latch mode, Enable SSCG
  • y … Select the current limit threshold voltage (Typ.).
    1: 50 mV
    2: 70 mV
    3: 100 mV

DOCUMENT/CONTACT

Purchase

Technical Support

Package*1 Reliability*2
QFN0505-32B R1273L (-A)

*1: The package file includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and land pattern (foot pattern).
*2: Reliability file includes a reliability test report and a reflow profile.

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