Step-up DC/DC Controller General Description EC9215 Features The EC9215 is a single PWM, step‐ up DC‐ DC controller with low operating voltage application integrating softstart and short circuit detection function. The oscillator switching frequency on chip can be operated by terminating OSC pin to connect capacitor and resistor for adjustable operating frequency. Soft‐ start is adjusted with the external capacitor, which sets the input current ramp. Besides, the external compensation FB pin will apply the flexibility in the dynamic loop status, which allows using small and low equivalent series resistance (ESR) ceramic output capacitors. The EC9215 is available in a Pb‐ free, SOP‐ 8L and TSSOP-8L package. ●2.5 to 5.5V Input Voltage Range ●Adjustable Frequency: Maximum 1MHZ ●Incorporates Soft‐ Start Function ●Built‐ in Short‐ Circuit Detection Circuit (SCP) ●Low Operating Current: Maximum to 1mA ●Low Shutdown Current: Maximum to 1µA ●Under‐ Voltage Lockout ●Package: SOP‐ 8 and TSSOP‐ 8 ●Lead Free and Green Devices Available (RoHS Compliant) Applications ●LCD Display Power Source ●PDA, PMP, MP3 ●Digital Camera Pin Assignments Figure1 Pin Configuration of EC9215(Top View) Pin Description Pin Number Pin Name Description 1 INV Internal 0.5V reference voltage. Use a resistor divider to set the output voltage 2 SCP Soft‐ start and short‐ circuit detection, connects a capacitor from the pin to ground. 3 VDD Power supply input pin for IC voltage 4 CTL Output control pin. Low = operating mode; High = shutdown mode. 5 OUT External MOSFET driving pin. 6 GND GND 7 OSC Setting capacitor and resister to provide oscillation switching frequency adjustment. 8 FB E-CMOS Corp. (www.ecmos.com.tw) Error amplifier output pin. Setting circuit for IC compensation. Page 1 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Ordering Information Part Number Package Marking EC9215NNM1R SOP-8L EC9215NNE1R TSSOP-8L EC9215 LLLLL YYWWT Marking Information 1. LLLL：Last four number of Lot No 2. YYWW：Date Code 3. T：Internal Tracking Code Function Block Figure 2 Function Block Diagram of EC9215 E-CMOS Corp. (www.ecmos.com.tw) Page 2 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Absolute Maximum Ratings Parameter Symbol Unit Rating VDD Supply Voltage ‐ 0.3 to 7 V VIO Input/Output Pins ‐ 0.3 to 7 V TA Operating Ambient Temperature Range ‐ 40 to 85 ℃ TJ Junction Temperature Range ‐ 40 to 150 ℃ TSTG Storage Temperature Range ‐ 60 to 150 ℃ TSDR Maximum Lead Soldering Temperature, 10 Seconds 260 ℃ Recommended Operating Conditions Symbol Rating Parameter Min. Unit Typ. Max. ‐ 5.5 V VDD Supply Voltage 2.5 VINV Error Amplifier Invert Input Voltage -0.2 1 V VCTL Control Pin Input Voltage -0.2 VDD V CSCP SCP Pin Capacitor RT Timing Resistance 1.0 CT Timing Capacitor 100 FSW Oscillator Frequency 200 E-CMOS Corp. (www.ecmos.com.tw) 0.1 Page 3 of 15 3.3 600 uF 10 KΩ 270 pF 1000 KHz 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Electrical Characteristics (VDD = 3.3V, TA = 25°C unless otherwise specified) Parameters Symbol Test Condition Min. Typ. Max. Unit 2.5 ‐ 5.5 V ENTIRE DEVICE Supply Voltage VDD Supply Current IDD VDD=2.5V to 5.5V ‐ 0.7 1 mA Shutdown Current ISD CTL pin open or VDD ‐ 0.1 1 µA DMAX RT =3.3K, CT =270pF 80 85 92 % Maximum Duty Cycle UNDER‐ VOLTAGE LOCKOUT PROTECTION VDD Startup Threshold Voltage VTH ‐ 2.0 ‐ 2.4 V Hysteresis voltage VR ‐ ‐ 150 ‐ mV Voltage at Soft‐ Start Completion VSS ‐ 0.7 0.8 0.9 V Soft‐ Start Charge Current ICS VSCP =0V ‐ 0.7 ‐ 1.0 ‐ 1.5 µA Voltage at Soft‐ Start Completion VSS ‐ 0.7 0.8 0.9 V Soft‐ Start Charge Current ICS VSCP =0V ‐ 0.7 ‐ 1.0 ‐ 1.5 µA 0.7 0.8 0.9 V ‐ 0.7 ‐ 1.0 ‐ 1.5 µA 500 600 700 kHz SOFT‐ START SHORT CIRCUIT PROTECTION (SCP) Threshold Voltage VSCP Charge Current ISCP VSCP =0V SAWTOOTH WAVEFORM OSCILLATOR (OSC) Oscillator Frequency FOSC RT =3.3k, CT =270pF Frequency Stability for Voltage FDV VDD=2.5V to 5.5V ‐ 2 5 % Frequency Stability for Temperature FDT TA=‐ 40°C to 85°C ‐ 5 ‐ % VREF VFB=INV 0.490 0.5 0.510 20 ERROR AMPLIFIER Reference Voltage VREF Stability VDD= 2.5V to 5.5V 5 VREF Variation with Temperature TA=-40℃ to 85℃ 1 Transconductance gm Input Bias Current IB Output Voltage Range VOH 1000 INV=0V 1.6 VOL E-CMOS Corp. (www.ecmos.com.tw) 1300 mV % 1600 uA/V 1 uA 1.8 V 0.01 Page 4 of 15 V V 5J15N-Rev.F001 Step-up DC/DC Controller Parameters Symbol Test Condition EC9215 Min. Typ. Output Source Current INV=0V,FB=0.5V -150 Output Sink Current INV=1V,FB=0.5V 140 -180 ‐ 170 Max. Unit -210 uA 200 uA PWM CONTROLLER DRIVER Output Source Current ISOURCE Duty<5%,OUT=0V -150 -200 mA Output Sink Current ISINK Duty>5%,OUT=5V 150 200 mA VIL Active mode VIH Switch-off mode CONTROL BLOCK Control Voltage E-CMOS Corp. (www.ecmos.com.tw) Page 5 of 15 0.2VDD 0.8VDD 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Typical Application Circuit E-CMOS Corp. (www.ecmos.com.tw) Page 6 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Typical Application Circuit E-CMOS Corp. (www.ecmos.com.tw) Page 7 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Timing Diagram E-CMOS Corp. (www.ecmos.com.tw) Page 8 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Typical Performance Characteristics (TA=25,VDD=3.3V,unless otherwise specified) E-CMOS Corp. (www.ecmos.com.tw) Page 9 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Typical Performance Characteristics(Cont.) (TA=25,VDD=3.3V,unless otherwise specified) E-CMOS Corp. (www.ecmos.com.tw) Page 10 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Typical Performance Characteristics(Cont.) E-CMOS Corp. (www.ecmos.com.tw) Page 11 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Function Description Setting Oscillating Frequency The oscillator circuit generates a triangular saw tooth wave with a peak of 0.9V and through 0.16V using the timing capacitor (CT) and the timing resistor (RT ) that are connected to OSC pin. This oscillator can provide oscillating frequency up to 1MHz Setting Output Voltage The output voltage is set using the INV pin and a resistor divider connected to the output is shown in the Typical Operating Circuit. The internal reference voltage is 0.5V with 2% variation, so the ratio of the feedback resistors sets the output voltage according to the following equation: To avoid the thermal noise from feedback resistor, the resistance R2 is smaller than 100kW and 1% variation is recommended. Error Amplifier The error amplifier detects the output voltage of the switching regulator and outputs the PWM control signal. The voltage gain is fixed, and connecting a phase compensation resistor and capacitor to the FB pin (pin 8) provides stable phase compensation for the system. PWM Comparator The voltage comparator has one inverting and three non-inverting inputs. The comparator is a voltage/pulse width converter that controls the ON time of the output pulse depending on the input voltage. The output level is high (H) when the saw-tooth wave is lower than the error amplifier output voltage, soft‐ start setting voltage, and idle period setting voltage E-CMOS Corp. (www.ecmos.com.tw) Page 12 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Output Circuit The output circuit is a typical push‐ pull configuration to drive an external NMOS transistor directly. It can provide a 200mA source/sink to/from OUT (pin 5). Soft-Start and Short Circuit Detection Soft-start operation is set by connecting capacitor CSCP to the SCP pin (pin 2).Soft-start prevents a current spike on start-up. On completion of the soft‐ start operation, the SCP pin (pin 2) stays low and enters the short circuit detection wait state. When an output short circuit occurs, the error amplifier output is fixed at 1.8V and capacitor CSCP starts charging. After charging to approximately 0.8 V, the output pin (pin5) is set low and the SCP pin stays low. Once the protection circuit operates, the circuit can be restored by resetting the power supply. Short circuit detection time can be calculate as below: Under-Voltage Lock Out (UVLO) Transients during powering on or instantaneous glitches in the supply voltage can cause system damage or failure. The circuit prevents malfunction at low input voltage detects a low input voltage by comparing the supply voltage with the internal reference voltage. On detection, the circuit fixes the output pin to low. The system recovers when the supply voltage rises back above the threshold voltage of thermal function prevention circuit. Layout Consideration Switching Noise Decoupling Capacitor A 0.1uF ceramic capacitor should be placed close to the VOUT pin and the GND pin of the chip to filter the switching spikes in the output voltage monitored by the VOUT pin. Feedback Network The feedback networks should be connected directly to a dedicated analog ground plane and this ground plane must connect to the GND pin. If no analog ground plane is available, and then this ground must tie directly to the GND pin. The feedback network, resistors R2 and R3, should be kept close to the FB pin, and away from the inductor. Input Capacitor The input capacitor CIN in VIN must be placed close to the IC. This will reduce copper trace resistance which effects input voltage ripple of the IC. For additional input voltage filtering, a 1uF capacitor can be placed in parallel with CIN, close to the VDD pin, to shunt any high frequency noise to the ground. E-CMOS Corp. (www.ecmos.com.tw) Page 13 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Package Information SOP-8L Package Outline Dimensions E-CMOS Corp. (www.ecmos.com.tw) Page 14 of 15 5J15N-Rev.F001 Step-up DC/DC Controller EC9215 Package Information TSSOP-8L Package Outline Dimensions E-CMOS Corp. (www.ecmos.com.tw) Page 15 of 15 5J15N-Rev.F001