CS5112 CHERRY
Document overview
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Technical content
Features
5V ± 2% @ 100mA n Switching Regulator 1.4A Peak Internal Switch 120kHz Maximum Switching Frequency 5V to 26V Operating Supply Range n Smart Functions Watchdog n Protection Overtemperature Current Limit ENABLE RESET Package Options
24 Lead SO Wide
(Internally Fused Leads) CS5112 1.4A Switching Regulator with 5V , 100mA Linear Regulator with Watchdog, RESET and ENABLE VREG VLIN IBIAS Gnd Gnd Gnd Gnd RESET CDelay WDI COSC VIN NC NC VSW Gnd Gnd Gnd Gnd V FB1 VFB2 SELECT COMP ENABLE CS5112
Description
1.25V V REG 1.4A VSW COMP VFB1 VFB2 SELECT VLIN IBIAS CDELAY RESET & Watchdog Timer Current Limit WDI COSC Base Drive RESET Gnd Bandgap Reference Oscillator Multiplexer COMP Logic - Switcher Shutdown Switcher Error Amplifier Current Sense Amplifier ENABLE Block Diagram A Company ¨ Rev. 4/22/99 Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786 Email: info@cherry-semi.com Web Site: www.cherry-semi.com The CS5112 is a dual output power sup- ply integrated circuit. It contains a 5V ±2%, 100mA linear regulator, a watchdog timer, a linear output voltage monitor to provide a Power On Reset (POR) and a 1.4A current mode PWM switching reg- ulator. The 5V linear regulator is comprised of an error amplifier, reference, and super- visory functions. It has low internal sup- ply current consumption and provides 1.2V (typical) dropout voltage at maxi- mum load current. The watchdog timer circuitry monitors an input signal (WDI) from the micro- processor. It responds to the falling edge of this watchdog signal. If a correct watchdog signal is not received within the externally programmable time, a reset signal is issued. The externally programmable active reset circuit operates correctly for an out- put voltage (V LIN) as low as 1V. During power up, or if the output voltage shifts below the regulation limit, tog- gles low and remains low for the duration of the delay after proper output voltage regulation is restored. Additionally a reset pulse is issued if the correct watchdog is not received within the programmed time. Reset pulses continue until the cor- rect watchdog signal is received. The reset pulse width and frequency, as well as the Power On Reset delay, are set by one external RC network. The current mode PWM switching regu- lator is comprised of an error amplifier with selectable feedback inputs, a cur- rent sense amplifier, an adjustable oscil- lator, and a 1.4A output power switch with anti-saturation control. The switch- ing regulator can be configured in a variety of topologies. The CS5112 is load dump capable and has protection circuitry which includes current limit on the linear and switcher outputs, and an overtemperature limiter. RESET
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Absolute Maximum Ratings VIN, VREG: RESET RESETENABLE Electrical Characteristics: 5V ² VIN ² 26V and -40¡C ² TJ ² 150¡C, -40¡C ² TA ² 85¡C, COUT = 100µF (ESR²8½), CDelay = 0.1µF, RBIAS = 64.9k½, COSC = 390 pF, CCOMP = 0.1µF; unless otherwise specified. n General IIN Off Current 6.6V ² V IN ² 26V, ISW = 0A 2.0 mA IIN On Current 6.6V ² V IN ² 26V, ISW = 1.4A 30 70 mA IREG Current I LIN = 100mA, 6.6V ² VREG ² 26V 6 mA Thermal Limit Guaranteed by design 160 210 ¡C n 5V Regulator Section VLIN Output Voltage 6.6V ² V REG ² 26V, 1mA ² ILIN ² 100mA 4.9 5.0 5.1 V Dropout Voltage (V REG - VLIN) @ ILIN = 100mA 1.2 1.5 V Line Regulation 6.6V ² V REG ² 26V, ILIN = 5mA 5 25 mV Load Regulation V REG = 19V, 1mA ² ILIN ² 100mA 5 25 mV Current Limit 6.6V ² V REG ² 26V 120 mA DC Ripple Rejection 14V ² V REG ² 24V 60 75 dB n Section Low Threshold (VRTL)V LIN Decreasing 4.05 4.25 4.45 V High Threshold (VRTH)V LIN Increasing 4.20 4.45 4.70 V Hysteresis V RTH - VRTL 140 190 240 mV Active High V LIN > VRTH, IRESET = -25µA V LIN - 0.5 V Active Low V LIN = 1V, 10k½ pullup from to V LIN 0.4 V VLIN = 4V, IRESET = 1mA 0.7 V Delay Invalid WDI 6.25 8.78 11.0 ms Power On Delay V LIN crossing VRTH 6.25 ms RESET RESET
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT CS5112 n Watchdog Input (WDI) VIH Peak WDI needed to activate 2.0 V VIL 0.8 V Hysteresis Note 1 25 50 mV Pull-Up Resistor WDI=0V 20 50 100 k½ Low Threshold 6.25 8.78 11.0 ms Floating Input Voltage 3.5 V WDI Pulse Width 5µ s n Switcher Section Minimum Operating 5.0 V Input Voltage Switching Frequency Refer to Figure 1d. 80 95 110 kHz Switch Saturation Voltage I SW = 1.4A 0.7 1.1 1.6 V Output Current Limit 1.4 2.5 A Max Switching Frequency V SW = 7.5V with 50½ load, 120 kHz Refer to Figure 1d. VFB1 Regulation Voltage 1.206 1.25 1.294 V VFB2 Regulation Voltage 1.206 1.25 1.294 V VFB1, VFB2 Input Current V FB1 = VFB2 = 5V 1 µA Oscillator Charge Current C OSC = 0V 35 40 45 µA Oscillator Discharge Current C OSC = 4V 270 320 370 µA CDelay Charge Current C Delay = 0V 35 40 45 µA Switcher Max Duty Cycle V SW = 5V with 50½ load, 72 85 95 % VFB1 = VFB2 = 1V Current Sense Amp Gain I SW = 2.3A 7 Error Amp DC Gain 67 dB Error Amp Transconductance 2700 µA/V n Input VIL 0.8 1.24 V VIH 1.30 2.0 V Hysteresis 60 mV Input Impedance 10 20 40 k½ n Select Input VIL (Selects V FB1) 4.9 ² V LIN ² 5.1 0.8 1.25 V VIH (Selects VFB2) 4.9 ² V LIN ² 5.1 1.25 2.0 V SELECT Pull-Up SELECT = 0V 10 24 50 k½ Floating Input Voltage 3.5 4.5 V Note 1: Guaranteed by Design, not 100% tested in production. ENABLE RESET Electrical Characteristics: 5V ² VIN ² 26V and -40¡C ² TJ ² 150¡C, -40¡C ² TA ² 85¡C, COUT = 100µF (ESR²8½), CDelay = 0.1µF, RBIAS = 64.9k½, COSC = 390 pF, CCOMP = 0.1µF; unless otherwise specified.
Typical Performance Characteristics 0A 20mA 40mA 60mA 80mA 100mA 3.5mA 4.0mA 4.5mA ILIN IREG - ILIN -30mA -40mA 0A 0.5A ISW -20mA -10mA 1.0A 1.5A 2.0A IIN ISW 0A 0.5A 1.0A 1.5A 2.0A 0.4V 0.0V 0.6V 0.8V 1.2V 1.0V VSW 0.2V 1.4V Package Lead Description PACKAGE LEAD # LEAD SYMBOL FUNCTION CS5112 COSC (pF) 120 160 1000 Frequency (kHz) 100 140 2000 3000500 1500 2500 180 Figure 1c. Switch Saturation Voltage. Figure 1d. Oscillator Frequency (kHz) vs. COSC (pF), assuming RBIAS = 64.9k½. 1V IN Supply Voltage. 2, 3 NC No connection. 4V SW Collector of NPN power switch for switching regulator section. 5,6,7,8,17,18,19,20 Gnd Connected to the heat removing leads. 9V FB1 Feedback input voltage 1 (referenced to 1.25V) 10 V FB2 Feedback input voltage 2 (referenced to 1.25V) 11 SELECT Logic level input that selects either V FB1 or VFB2. An open selects VFB2. Connect to Gnd to select VFB1. 12 COMP Output of the transconductance error amplifier. 13 C OSC A capacitor connected to Gnd sets the switching frequency. Refer to Figure 1d. 14 WDI Watchdog input. Active on falling edge. 15 C Delay A capacitor connected to Gnd sets the Power On Reset and Watchdog time. 16 output. Active low if V LIN is below the regulation limit. If watchdog timeout is reached, a reset pulse train is issued.
21 I BIAS A resistor connected to Gnd sets internal bias currents as well as
the COSC and CDelay charge currents. 22 V LIN Regulated 5V output from the linear regulator section.
23 V REG Input voltage to the linear regulator and the internal supply cir-
cuitry. 24 Logic level input to shut down the switching regulator.ENABLE RESETRESET
the maximum inductance and peak current. sure the inductor current doesnÕt exceed 1.4A. mum ESR based on the allowable output voltage ripple. parallel, the equivalent ESR can be reduced. before being applied to the input of the error amplifier. For the CS5112, gm = 2700µA/V typical.
- This is shown by the line AB with a -
Figure 9. RC network used to compensate the error amplifier (OTA).
2 POUT/h
CS5112EDWF24 24 Lead SO Wide (internally fused leads) CS5112EDWFR24 24 Lead SO Wide (internally fused leads) (tape & reel) Rev. 4/22/99 Thermal 24 Lead SO Wide Data (internally fused leads) RQJC typ 9 ûC/W RQJA typ 55 ûC/W Package Specification PACKAGE THERMAL DATA
Ordering Information
D Lead Count Metric English Max Min Max Min 24 Lead SO Wide 15.60 15.20 .614 .598 (internally fused leads) PACKAGE DIMENSIONS IN mm (INCHES) CS5112 © 1999 Cherry Semiconductor Corporation Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information. Surface Mount Wide Body (DW); 300 mil wide 1.27 (.050) BSC 7.60 (.299) 7.40 (.291) 10.65 (.419) 10.00 (.394) D 0.32 (.013) 0.23 (.009) 1.27 (.050) 0.40 (.016) REF: JEDEC MS-013 2.49 (.098) 2.24 (.088) 0.51 (.020) 0.33 (.013) 2.65 (.104) 2.35 (.093) 0.30 (.012) 0.10 (.004)