Description Features GM3326 is step-up/down DC/DC converter controller ICs Input Voltage Range : 2.0V ~ 10V with fast, and low ON resistance drivers built-in. A versatile Output Voltage Range : 2.4V ~ 6.0V ( ± 2.5% step-up/ down DC/DC converter can be realised by using accuracy) (selectable in 0.1V steps) with large output current only 4 basic external components Oscillation Frequency : 300KHz ( ± 15% - transistors, coils, diodes, and capacitors. accuracy) Output voltage is selectable in 0.1V steps within a 2.4V ~ 6.0V ( ± 2.5% accuracy) range, and switching frequency is set at or 300KHz. Output Current : more than 250mA (VIN=2.4V, GM3326 switches from PWM to PFM control during light loads, and the series offers high efficiencies from light loads through to large output currents. Efficiency : 81% (typ) at 5.0V, 78% (typ) at 3.3V Soft-start time is internally set to 10 msec, which offers protection against rush currents when the power is switched on and also against voltage overshoot. SOT-25 Package VOUT=3.3V) Stand-By : ISTB = 0.5µA (max) Output Voltage Internal Set-Up During shutdown (CE pin = L), consumption current can be reduced to as little as 0.5µA or less. Application Mobile phones PDAs Palmtop computers Portable audio equipment Various power supplies TYPICAL APPLICATION CIRCUITS Schottky MBRS140 3L colis SMTSPR5D5047C-220 Youth coils YCDH57-220 L VOUT Nch MOSFET FDN339AN VOUT 68µF/ 10V Chemi_con PT- Series Schottky MBRS140 VDD GND + CIN 100µF/ 10V Chemi_con PT- Series www.gammamicro.com GM3326 V0.1 CL CE VIN EXT GM3326 + Pch MOSFET FDN338P 1 MARKING INFORMATION & PIN CONFIGURATIONS SOT-25 (SOT-23-5) CE VOUT 5 4 OA: Device Code V : Output Voltage Y : Year W : Weekly OAVYW 1 3 2 EXT GND VDD ORDERING INFORMATION Output Voltage Suffix Package Shipping GM3326-2.5ST25R 2.5 B SOT-25 3,000 Units/ Tape & Reel GM3326-2.8ST25R 2.8 E SOT-25 3,000 Units/ Tape & Reel GM3326-3.0ST25R 3.0 G SOT-25 3,000 Units/ Tape & Reel GM3326-3.3ST25R 3.3 J SOT-25 3,000 Units/ Tape & Reel GM3326-3.5ST25R 3.5 L SOT-25 3,000 Units/ Tape & Reel GM3326-4.0ST25R 4.0 Q SOT-25 3,000 Units/ Tape & Reel GM3326-4.5ST25R 4.5 V SOT-25 3,000 Units/ Tape & Reel GM3326-5.0ST25R 5.0 A SOT-25 3,000 Units/ Tape & Reel GM3326-5.5ST25R 5.5 F SOT-25 3,000 Units/ Tape & Reel GM3326-6.0ST25R 6.0 K SOT-25 3,000 Units/ Tape & Reel Ordering Number * For detail Ordering Number identification, please see last page. ABSOLUTE MAXIMUM RATINGS SYMBOL RATINGS UNITS VDD Pin Voltage VDD -0.3 ~ 12 V VOUT Pin Voltage VOUT -0.3 ~ 12 V VCE -0.3 ~ 12 V EXT/ Pin Voltage VEXT/ -0.3 ~ VDD +0.3 V EXT/ Pin Current IEXT/ ± 100 mA Power Dissipation Pd 150 mW Operating Ambient Temp. Topr -40 ~ +85 °C Storage Temp. Tstg -40 ~ +125 °C PARAMETER GM3326 CE Pin Voltage 2 BLOCK DIAGRAM VOUT VDD Phase Compensation Error Amp. + + - Buffer, Driver EXT/ PWM/ PFM Comparator CE VRef with Soft Start CE PWM/ PFM Controller Ramp Wave Generator, OSC GND Block Diagram Explanation <Error Amp.> The error amplifier is used as an output voltage monitor. It compares the reference voltage with the feedback from the voltage divided by the internal resistor. Should a voltage higher than the reference voltage be fedback, the output of the error amp will increase. <PWM Comparator> The PWM comparator compares the output of the error amp with the ramp wave. When the voltage at the output of the error amp is low, the EXT/ pin will be LOW level (Switching ON time). <Ramp Wave Generator> The ramp wave generator, as the name suggests, generates the switching frequency's ramp wave. <PWM / PFM Controller> With the GM3326 series, control is automatically switched between PWM and PFM according to the size of the load. <Vref with Soft Start, CE> The start up of the Vref voltage at the error amp's input is gradual due to the internal capacitor and low current circuit. Because of this soft-start function, the operations of the error amp's 2 inputs are balanced and the EXT/ pin's ON time can be manipulated to produce longer ON times. GM3326 Further, with the UVLO function, the signal will be such so as not to turn the MOS switch ON until any instability in the internal circuit stabilizes during soft-start time. Even in cases where input voltage is so low as to produce instability in the IC, the UVLO function will operate and the MOS switch will be turned OFF. 3 [Step-up&down DC/DC Converter] Set output voltage obtained as a result of the automatic switching operations of the IC regardless of the difference between input voltage and set output voltage. 90 Efficiency (%) 85 80 75 70 IOUT= 10mA 65 60 200mA 100mA Set Output Voltage +0.4V 55 50 Step-Up Mode Step-Down Mode 45 40 2 3 4 5 6 7 8 Input Voltage (V) Figure 1. Input Voltage vs. Efficiency The above graph shows that over a wide input voltage range, the efficiency of the GM3326 is more or less constant. In applications that use either a standard dry 3 cell battery or a cell lithium Ion battery to obtain an output of 3.3V, for example, the efficiency of GM3326 is again much better. Due to GM3326 does not have a series regulator output, we recommend a test with samples for use in applications where ripple voltage is a problem. External Components Selection (Notes) The performance of the DC/DC converter IC circuit is heavily reliant upon the performance of the surrounding circuitry and components. In particular, since the VF voltage of the Schottky Diode used will have a direct effect upon efficiency, the smaller the diode, the better the efficiency obtainable. (Refer to the graph below) It is also recommended that a switching MOSFET with a small ON resistance be used. With GM3326, an ON resistance of 500mW or less is recommended. Efficiency (%) 85 80 75 GM3326 VIN= 3.0V VIN= 4.5V 70 65 0.2 4 VIN= 2.4V 0.4 VF Voltage (V) Figure 2. VOUT= 3.3V, IOUT= 100mA OPERATIONAL EXPLANATION Schottky L Pch MOSFET VOUT VIN Nch MOSFET Schottky VOUT EXT VIN CE + CE GND CL + CIN <Circuit Connection Example> GM3326 is PWM (PWM/ PFM switching) step-up/down DC/DC converter controller ICs. Gm3326 switches to PFM operations during light loads and is very efficient over a wide range in relation to load. Further, the efficiency can be maintained over a wide input voltage range as both step-up & step-down operations are PWM controlled. Output voltage settings are laser trimmed. [ON TIME] P-Ch MOSFET = ON, N-Ch MOSFET = ON : Current flows from VIN via Pch MOSEFT, L, Nch FET to GND : L is charged. [OFF TIME] P-Ch MOSFET (PSW) = OFF, N-Ch MOSFET (NSW) = OFF : Current flows from GND via Schottky 1, L, Schottky 2, to VOUT : VOUT rises due to the charge stored at L. By comparing VOUT with the internal reference voltage, the ON TIME vs OFF TIME ratio can be regulated & output stability can be protected. ELECTRICAL CHARACTERISTICS (GM3326- 3.3V) TA= 25°C Min Typ Max Unit 3.218 3.300 3.383 V 2.0 - 10.0 V 130 200 µA 20 35 µA - 0.5 µA 300 345 KHz PARAMETER SYMBOL Output Voltage VOUT Supply Voltage VDD Supply Current 1 IDD 1 VOUT= CE: Set Output Voltage X 0.95 applied - Supply Current 2 IDD 2 VOUT= CE: Set Output Voltage + 0.5 applied - Stand- By Current ISTB VOUT= Set Output Voltage X 0.95 applied, CE= 0V - Oscillation Frequency FOSC VDD=VOUT= CE: Set Output Voltage X 0.95 applied 255 CONDITIONS Max. Duty Ratio MAXDTY VDD=VOUT= CE: Set Output Voltage X 0.95 applied 78 85 92 % PFM Duty Ratio PFMDTY 15 25 35 % - 78 - % 5.0 10.0 20.0 mS Efficiency Note 1 EFFI No load VDD=VIN= CE: Set Output Voltage X 0.95 applied Soft- Start Time TSS CE 'H' Voltage VCEH VOUT: Set Output Voltage X 0.95 applied 0.65 - - V CE 'L' Voltage VCEL VOUT: Set Output Voltage X 0.95 applied - - 0.20 V Same as IDD 1, VEXT/ = VOUT - 0.4V - 29 43 W Same as IDD 1, VEXT/ = 0.4V - 19 27 W EXT/ 'H' ON Resistance EXT/ 'L' ON Resistance REXTBH REXTBL Measuring Condition: Unless otherwise stated, VDD = 3.3V, IOUT = 130mA Note 1: EFFI= {[(Output Voltage) X (Output Current)] [(Input Voltage) X (Input Current)]} X100 GM3326 VOUT= 3.3V, FOSC= 300kHz 5 SOT-25(SOT-23-5) PACKAGE OUTLINE DIMENSIONS 2.9 ± 0.1 1.9 ± 0.05 0.13 0.95 ± 0.038 Pad Layout 0.028 0.7 0~0.1 1.5 ± 0.05 0.039 1.0 2.8 ± 0.1 0.094 2.4 0.65 ± 0.05 0.8 ± 0.05 0.35 ± 0.03 0.037 0.95 5° 0.037 0.95 0.074 1.9 5° 1.10 ± 0.1 Unit: mm ORDERING NUMBER GM 3326 2.5 ST25 R Shipping R: Tape & Reel Gamma Micro. GM3326 Package ST25: SOT-25 6 Circuit Type Output Voltage 1.5: 1.5V ( Inches mm ) 7 GM3326