cherry semiconductor CS8127 数据手册

5V Linear Controller/Driver
Description
Note 1: Dependent on characteristics of external transistor.
Power Dissipation.............................................................................................................................................Internally Limited Input Voltage..................................................................................................................................................................Ð0.3V, 26V Transient Input Voltage............................................................................................................................................................60V Output Current...............................................................................................................................................Externally Limited ESD Susceptibility (Human Body Model)..............................................................................................................................2kV Junction Temperature............................................................................................................................................Ð45¡C to 150¡C Storage Temperature..............................................................................................................................................Ð55¡C to 150¡C Lead Temperature Soldering
Wave Solder (through hole styles only).....................................................................................10 sec. max, 260¡C peak Reflow (SMD styles only)......................................................................................60 sec. max above 183¡C, 230¡C peak
C S 8127
Typical Performance Characteristics (per Test Circuit)
5.025.015
4.994.984.974.96
4.95
-40
JUNCTION TEMPERATURE (°C)
V O U T (V )
RESET OUTPUT CURRENT (mA)
R E S E T O U T P U T V O L T A G E (m V )
V IN (V)
I Q (m A )
I Q vs. V IN
Temperature Performance of V OUT
V IN (V)
V O U T (V
)
I OUT (Amps)
D R O P O U T V O L T A G
E (m V )I OUT (Amps)
L O A D R E G U L A T I O N (m V )Load Regulation vs. I OUT
Dropout Voltage vs. I OUT
V OUT vs. V IN
I OUT (Amps)
L I N E R E G U L A T I O N (m V )I OUT (Amps)
I Q (m A )FREQUENCY (Hz)
V I N / V O U T (d B )Ripple Rejection
I Q vs. I OUT
Line Regulation vs. I OUT
The CS8127 function is very precise, has hysteresis on both the and Delay comparators, a latching Delay capacitor discharge circuit, and operation down to 1V.
The reset circuit output is an open collector type with ON and OFF parameters as specified. The reset output NPN transistor is controlled by the Low Voltage Inhibit and Reset Delay circuits (see Block Diagram).
This circuit monitors output voltage, and when output voltage is below V RTL , causes the reset output transistor to be in the ON (saturation) state. When the output voltage is above V RTH , this circuit permits the reset output transistor to go into the OFF state if allowed by the reset Delay cir-cuit.
This circuit provides a programmable (by external capaci-tor) delay on the output lead. The Delay lead pro-vides source current to the external delay capacitor only when the Low Voltage Inhibit circuit indicates that output voltage is above V RTH . Otherwise, the Delay lead sinks current to ground (used to discharge the Delay capacitor).The discharge current is latched ON when the output volt-age falls below V RTL . The Delay capacitor is fully dis-charged anytime the output voltage falls out of regulation,even for a short period of time. This feature ensures a con-trolled pulse is generated following the detection of an error condition. The circuit allows the out-put transistor to go to the OFF (open) state only when the voltage on the Delay lead is higher than V DTC .
RESET RESET RESET RESET Delay Circuit
Low Voltage Inhibit Circuit
RESET RESET
127
RESET Circuit Functional Description
Application Information
The CS8127 includes an over voltage shutdown circuit.Shutdown typically occurs at 36V.
The CS8127 includes a thermal shutdown circuit that dis-ables the output when junction temperature exceeds approximately 180ûC. This is a self-protection feature
designed to protect the CS8127. The thermal shutdown cir-cuit does not monitor the temperature of the pass transis-tor, which will probably be much hotter. To optimize ther-mal shutdown, board design should minimize the differ-ence in temperature of the CS8127 and the pass device.
External Pass Device - Select a pass device that will deliv-er the desired output current, withstand the maximum expected input voltage, and dissipate the resulting power.The CS8127 is compatible with a wide variety of Bipolar and FET pass transistors.
Output Capacitor - An output capacitor is required for sta-bility in most applications. Though a 10µF capacitor should be sufficient, regulator stability is dependent on the characteristics of the pass transistor. Capacitor effective series resistance (ESR) also factors in system stability. Some bench work may be required to determine the capacitor characteristics required for use in a particular application.BIAS Resistor - This resistor provides bias current for the CS8127 output stage, and prevents the pass device from ÒleakingÓ. It also speeds the turn-off of the pass device during an overvoltage transient. For proper operation over temperature, the recommended value is 560½, although it
may be increased or decreased for a particular application.R OUT Resistor - This resistor controls the drive current available to the pass transistor. It also determines regula-tor start-up current and short circuit current limit. For
bipolar pass transistors, it can be selected by use of the fol-lowing formulae:
R OUT =
x §Q1*** ***b Q1= Pass transistor minimum b @ maximum output current.
Typical start-up current and current limit can be calculat-ed as follows:
I START Å
+ 5mA I Limit Åx §Q1@ Current Limit
For example, if the minimum input voltage is 6V, maxi-mum output current is 1Amp, and minimum transistor b @ 1Amp is 60, then R OUT can be calculated as follows:
R OUT Åx 60 = 300½
I Start Å
+ 5mA = 18.3mA
With V IN = 14V, and a pass transistor b of 40 @ current limit:
I Limit Å
x 40 = 1.7Amps 14V Ð 1V
300½
4V 300½
6V Ð 1V
1Amp V IN Ð 1V
R OUT
4V
R OUT
V IN(min)Ð 1V
I OUT(max)External Component Selection
Thermal Shutdown
Overvoltage Shutdown
Part Number Description CS8127YN88 Lead PDIP
CS8127YD88 Lead SO Narrow
CS8127YDR8
8 Lead SO Narrow (tape & reel)
Ordering Information
D
Lead Count Metric English
Max Min Max Min 8L PDIP
10.169.02.400.3558L SO Narrow
5.00 4.80
.197.189
Thermal Data 8 Lead 8 Lead PDIP SO Narrow R Q JC typ 5245ûC/W
R Q JA
typ
100165
ûC/W
C S 8127
Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information.。