CS5111 Datasheet, PDF (1/10 Pages) Cherry Semiconductor Corporation – 1.4A Switching Regulator with 5V, 100mA Linear Regulator with Watchdog, RESET and ENABLE

CS5111
1.4A Switching Regulator with 5V, 100mA Linear
Regulator with Watchdog, RESET and ENABLE
Description
Features
The CS5111 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, RESET 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 CS5111 is load dump capable and
has protection circuitry which includes
overvoltage shutdown, current limit on
the linear and switcher outputs, and an
overtemperature limiter.
Block Diagram
s Linear Regulator
5V ± 2% @ 100mA
s Switching Regulator
1.4A Peak Internal
Switch
120kHz Maximum
Switching Frequency
5V to 26V Operating
Supply Range
s Smart Functions
Watchdog
RESET
ENABLE
s Protection
Overvoltage
Overtemperature
Current Limit
s 54V Peak Transient
Capability
VFB1
VFB2
SELECT
COMP
IBIAS
COSC
VREG
CDELAY
WDI
Multiplexer
Oscillator
Switcher
Error Amplifier
-
COMP
Logic
Base
Drive
Current Sense Amplifier
-
Switcher Shutdown
1.4A
VIN
VSW
Gnd
ENABLE
Over Voltage
Bandgap
Reference
Linear
-
Error Amplifier
1.25V
Current
Limit
Over
Temperature
VLIN
RESET &
Watchdog Timer
RESET
Package Option
24 Lead SO Wide
(Internally Fused Leads)
V_IN 1
NC
NC
V_SW
Gnd
ENABLE
V_REG
V_LIN
I_BIAS
Gnd
Gnd
Gnd
Gnd
Gnd
Gnd
Gnd
V_FB1
V_FB2
RESET
C_Delay
SELECT
WDI
COMP
C_OSC
Rev. 12/28/98
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: [phone] Fax: [phone]
Email: [e-mail]
Web Site: www.cherry-semi.com
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A
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