Cherry Semiconductor CS5112EDWFR24, CS5112EDWF24 Datasheet
1
Features
■ Linear Regulator
5V ± 2% @ 100mA
■ Switching Regulator
1.4A Peak Internal
Switch
120kHz Maximum
Switching Frequency
5V to 26V Operating
Supply Range
■ Smart Functions
Watchdog
■ 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
V
REG
V
LIN
I
BIAS
Gnd
Gnd
Gnd
Gnd
RESET
C
Delay
WDI
C
OSC
V
IN
NC
NC
V
SW
Gnd
Gnd
Gnd
Gnd
V
FB1
V
FB2
SELECT
COMP
ENABLE
CS5112
Description
Over
Temperature
V
IN
Linear
Error Amplifier
1.25V
V
REG
1.4A
V
SW
COMP
V
FB1
V
FB2
SELECT
V
LIN
I
BIAS
C
DELAY
RESET &
Watchdog Timer
Current
Limit
WDI
C
OSC
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 supply 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 regulator.
The 5V linear regulator is comprised of
an error amplifier, reference, and supervisory functions. It has low internal supply current consumption and provides
1.2V (typical) dropout voltage at maximum load current.
The watchdog timer circuitry monitors
an input signal (WDI) from the microprocessor. 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 output voltage (V
LIN
) as low as 1V. During
power up, or if the output voltage shifts
below the regulation limit, toggles 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 correct 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 regulator is comprised of an error amplifier
with selectable feedback inputs, a current sense amplifier, an adjustable oscillator, and a 1.4A output power switch
with anti-saturation control. The switching 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
1
2
CS5112
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Absolute Maximum Ratings
Logic Inputs/Outputs ( , SELECT, WDI, ) ................................................................................-0.3V to V
LIN
V
LIN
................................................................................................................................................................................-0.3V to 10V
VIN, V
REG:
DC Input Voltage .................................................................................................................................................-0.3V to 26V
Peak Transient Voltage (26V Load Dump @ 14V VIN)....................................................................................-0.3V to 40V
VSWPeak Transient Voltage .....................................................................................................................................................54V
C
OSC
, C
Delay
, COMP,V
FB1
, V
FB2
..................................................................................................................................-0.3V to V
LIN
Power Dissipation.............................................................................................................................................Internally Limited
V
LIN
Output Current ........................................................................................................................................Internally Limited
VSWOutput Current .........................................................................................................................................Internally Limited
Output Sink Current ..................................................................................................................................................5mA
ESD Susceptibility (Human Body Model)..............................................................................................................................2kV
ESD Susceptibility (Machine Model).....................................................................................................................................200V
Storage Temperature...................................................................................................................................................-65 to 150¡C
Lead Temperature Soldering: Reflow (SMD styles only) ..........................................60 sec. max above 183¡C, 230¡C peak
RESET
RESETENABLE
Electrical Characteristics: 5V ² V
IN
² 26V and -40¡C ² TJ ² 150¡C, -40¡C ² TA² 85¡C, C
OUT
= 100µF (ESR²8½),
C
Delay
= 0.1µF, R
BIAS
= 64.9k½, C
OSC
= 390 pF, C
COMP
= 0.1µF; unless otherwise specified.
■ General
I
IN
Off Current 6.6V ² VIN² 26V, I
SW
= 0A 2.0 mA
IINOn Current 6.6V ² VIN² 26V, I
SW
= 1.4A 30 70 mA
I
REG
Current I
LIN
= 100mA, 6.6V ² V
REG
² 26V 6 mA
Thermal Limit Guaranteed by design 160 210 ¡C
■ 5V Regulator Section
V
LIN
Output Voltage 6.6V ² V
REG
² 26V, 1mA ² I
LIN
² 100mA 4.9 5.0 5.1 V
Dropout Voltage (V
REG
- V
LIN
) @ I
LIN
= 100mA 1.2 1.5 V
Line Regulation 6.6V ² V
REG
² 26V, I
LIN
= 5mA 5 25 mV
Load Regulation V
REG
= 19V, 1mA ² I
LIN
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
■ Section
Low Threshold (V
RTL
)V
LIN
Decreasing 4.05 4.25 4.45 V
High Threshold (V
RTH
)V
LIN
Increasing 4.20 4.45 4.70 V
Hysteresis V
RTH
- V
RTL
140 190 240 mV
Active High V
LIN
> V
RTH
, I
RESET
= -25µA V
LIN
- 0.5 V
Active Low V
LIN
= 1V, 10k½ pullup from to V
LIN
0.4 V
V
LIN
= 4V, I
RESET
= 1mA 0.7 V
Delay Invalid WDI 6.25 8.78 11.0 ms
Power On Delay V
LIN
crossing V
RTH
6.25 ms
RESET
RESET
3
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
CS5112
■ 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 5µs
■ Switcher Section
Minimum Operating 5.0 V
Input Voltage
Switching Frequency Refer to Figure 1d. 80 95 110 kHz
Switch Saturation Voltage ISW= 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.
V
FB1
Regulation Voltage 1.206 1.25 1.294 V
V
FB2
Regulation Voltage 1.206 1.25 1.294 V
V
FB1
, V
FB2
Input Current V
FB1
= V
FB2
= 5V 1 µA
Oscillator Charge Current C
OSC
= 0V 35 40 45 µA
Oscillator Discharge Current C
OSC
= 4V 270 320 370 µA
C
Delay
Charge Current C
Delay
= 0V 35 40 45 µA
Switcher Max Duty Cycle VSW= 5V with 50½ load, 72 85 95 %
V
FB1
= V
FB2
= 1V
Current Sense Amp Gain ISW= 2.3A 7
Error Amp DC Gain 67 dB
Error Amp Transconductance 2700 µA/V
■ Input
VIL 0.8 1.24 V
VIH 1.30 2.0 V
Hysteresis 60 mV
Input Impedance 10 20 40 k½
■ Select Input
VIL (Selects V
FB1
) 4.9 ² V
LIN
² 5.1 0.8 1.25 V
VIH (Selects V
FB2
) 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 V
IN
² 26V and -40¡C ² TJ ² 150¡C, -40¡C ² TA² 85¡C, C
OUT
= 100µF (ESR²8½),
C
Delay
= 0.1µF, R
BIAS
= 64.9k½, C
OSC
= 390 pF, C
COMP
= 0.1µF; unless otherwise specified.
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